Posts with «grove» label

PobDuino Makes the Most of Grove

The chassis of a toy robot serves as the base of a robot built by [Jean Noel]. Called #PobDuino, the robot features two Arduino-compatible boards under the hood.

First, a Seeeduino Lotus, a Arduino board peppered with a dozen Grove-compatible sockets. The board, which is the size of an UNO, is mounted so that the plugs project out of the front of the robot, allowing ad-hoc experimentation with the various Grove System modules. Meanwhile, a custom ATmega328 board (the PobDuino) interprets Flowcode instructions and sends commands to the various parts of the robot: servos are controlled by an Adafruit servo driver board and the DC motors are driven by a Grove I2C motor driver.

We love how easy it is to customize the robot, with both the Lotus and the Adafruit 16-channel servo driver on the exterior of the robot. Just plug and play!

Learn more about Grove-compatible plugs and a lot more in [Elliot]’s My Life in the Connector Zoo.


Filed under: robots hacks
Hack a Day 27 Jul 09:00

My Life in the Connector Zoo

“The great thing about standards is that there are so many to choose from.” Truer words were never spoken, and this goes double for the hobbyist world of hardware hacking. It seems that every module, every company, and every individual hacker has a favorite way of putting the same pins in a row.

We have an entire drawer full of adapters that just go from one pinout to another, or one programmer to many different target boards. We’ll be the first to admit that it’s often our own darn fault — we decided to swap the reset and ground lines because it was convenient for one design, and now we have two adapters. But imagine a world where there was only a handful of distinct pinouts — that drawer would be only half full and many projects would simply snap together. “You may say I’m a dreamer…”

This article is about connectors and standards. We’ll try not to whine and complain, although we will editorialize. We’re going to work through some of the design tradeoffs and requirements, and maybe you’ll even find that there’s already a standard pinout that’s “close enough” for your next project. And if you’ve got a frequently used pinout or use case that we’ve missed, we encourage you to share the connector pinouts in the comments, along with its pros and cons. Let’s see if we can’t make sense of this mess.

FTDI TTL Serial

The de-facto standard for a hacker’s TTL serial pinout is definitely the layout that FTDI uses for their USB/TTL serial cables. Said cable is just so handy to have on hand that you’d be silly to use any other pinout for the job. And the good news is that the rest of the world has basically joined in. From the Chinese “Pro Mini” cloneduinos to the Hackaday Edition Huzzah ESP8266 board, and from Adafruit’s FTDI Friend to Modern Device’s USB-BUB, almost everyone uses this pinout. A victory for the common man!

There is one slight point of contention, however, and that’s whether pin 6 is DTR or RTS#. We never use either, so we couldn’t care less, but if you’re counting on your programmer sending the DTR signal to enter programming mode on the device (we’re looking at you Arduino!) then you’ll want DTR on pin 6, and the original FTDI cable, ironically, has the “wrong” pinout. Perhaps that’s why Sparkfun avoided the whole debacle and went their own way, breaking out every signal off the FTDI chip into their own unique configuration.

If you’re only going to break out TTL serial lines, you’d be a fool to use any other pinout.

Modules and Other Communications

Unlike the case with simple serial, connecting various kinds of modules to mainboards is a difficult problem. Creating a single pinout or connector specification for many potential protocols or arbitrary signals is a Herculean task. Surprisingly, it’s been done a few times over. Here are some notables.

Pmod

Digilent makes a wide range of FPGA demo boards, and they needed an in-house standard pinout that they could use to plug into various add-on peripheral modules that they sell. Thus Pmod was born. It has since become a full-fledged, and trademarked, open standard that you can use in your designs. Here’s the PDF version of the specification for you to print out, so you know they mean business.

There are a few aspects of Pmod that we think are particularly clever. First, the number of pins involved is “just right” at six, and it’s easily expandable. They use standard 0.1″ pitch pins and headers. Two lines carry power and ground, leaving four free pins for SPI, UART, or whatever else. The specification is that all power and signal voltages are 3.3 V because they’re designed for FPGAs after all. You can mix and match if you know what you’re doing, but they won’t let you call it Pmod(tm).

Eric Brombaugh’s iceRadio FPGA SDR, plugged together with Pmods

If you need more than four signals, there’s a twelve-pin version which is just two six-pin Pmods stacked into a double-row header. The extra power and ground are redundant, but it makes a twelve-pin output very flexible, because nothing stops it from being used as two sixes. The standard also says that the twelve-pin headers are to be spaced at 0.9″ center-to-center, so you can even connect two of them together when you need sixteen board-to-board signal connections. We like the modularity and expandability.

Pmod connectors are multi-protocol, but for each protocol there is a single pinout. So there’s an SPI Pmod and an I2C Pmod, and the pins are always in the same place. There isn’t a Pmod standard for every conceivable application, of course, so there’s a GPIO pinout that gives you free rein over what goes where. We think that it would be nice if some additional notable protocols (I2S? one-wire? servos? analog stereo audio?) were included in the specs, but the community can also handle these lower-level details.

In our eyes, Pmod is nearly perfect. It uses cheap hardware, is easily expandable, and the smallest incarnations are small enough to fit on all four sides of a one-inch-square board. If you’re willing to pay the brand-name premium, Digilent makes an incredible range of modules. We want to see more hackers outside of the FPGA scene get on it.

mikroBUS

What Digilent is to development boards in the US, MikroElektronika is in Europe. While Pmod aims to be capable of doing anything, Mikro-E’s mikroBUS connector wants to do everything, which is to say it has I2C, SPI, UART, two voltages, and even a few extra signals all on the same pinout. Physically, it’s two single rows of eight pins, spaced 0.9″ apart side-to-side, which means it fits into a breadboard nicely. Here’s the spec in PDF.

The tradeoff here, relative to Pmod, is that a lot of pins go unused on any given design. With (only) one “analog” channel, you wouldn’t choose mikroBUS to send stereo audio, whereas nothing stops you from calling the Pmod’s GPIO lines analog and sending four channels of sound. But that mikroBUS gains is fool-proofness. (Well, they could have also made it asymmetric…) There’s no chance of a newbie plugging an SPI module in where an I2C module is expected and scratching their heads. With mikroBus, it should just work.

Microchip has added a mikroBus port to their Curiosity boards, and MikroElektronika makes a ton of modules. If your audience consists of beginners, and one footprint for all protocols, it’s worth considering.

Seeed’s Grove

Meanwhile in China, Seeed Studios makes open-source modules, and makes them cheap. Their Grove connector uses only four pins, with power and ground among them. The have standard pinouts for UART, I2C, and for servo motors. Sensors and other analog peripherals are allocated one “primary” pin and one “secondary” and it’s assumed that you know what you’re doing. The idea behind their system is that you add a shield to your microcontroller board, and they break out the relevant pins into these four-pin Grove headers.

This is great for small things and I2C devices, which is Seeed’s catalog, but there just aren’t enough signal pins to run SPI or an analog RGB LED, for instance. But because of the small number of pins, they use very inexpensive polarized cables and shrouds that you can’t plug in the wrong way, and that take up relatively little board space. That’s Grove’s design trade-off.

Servo Motor control

One of these things is not like the others…

Hobby servo motors need three wires: voltage, ground, and a signal to tell them where to point. There are three distinct ways to arrange these wires, but Futaba, HiTec, Tower, GWS, and JR servos all chose to put them in SVG (or GVS) order, and there’s no reason to buck the trend. (Airtronics, what were you thinking?!)

SVG is also a handy pinout to use for all sorts of one-signal sensors or actuators where space is a premium, and we’ve seen this in a few designs (here and here, for instance). But we’re torn. Relative to the Grove, for instance, you’re just saving one pin. Even the Pmod would work with only three pins’ overhead. Is that worth complicating your life with another pinout? If you need a lot of powered one-signal devices, or servos, it probably is, and you can hardly beat SVG or GVS, whichever way you look at it.

Arduino

Viewed in the light of any of the other module interconnection systems, the Arduino is the worst of all worlds. It’s monolithic like mikroBUS, but it’s gigantic — you have to build a 55×73 mm board and accommodate 30 pins and pass-throughs if you’d like it to be stackable. The pins have a funny spacing (that gap!), that doesn’t fit any normal protoboard. Nobody goes through the trouble of building a shield just for an I2C connection. No wonder most Arduino projects look like a breadboard hedgehog. About the only good thing we can say about it is that it’s hard to plug one in backwards.

There’s also the tiny little factor that there’s a million Arduino shields out there, a huge community built around them, and widespread support for them. Which turns out to trump all of the reasonable design concerns. (Shakes head.)

Miscellany

Of course, there are other very specific pinouts that one might encounter, like the old ESP-01 module, or the XBee, or the nRF24. Adapting modules to fit boards is always going to be a pain, because the manufacturers will pick whatever suits them on that day. Programmer pinouts for specific microcontrollers are a similar story, as is JTAG, which is a beautiful standard with a dogs’ breakfast of pinout possibilities. (We could do a whole column!)

Faced with this inevitability, and the need for many one-off adapters, what can you do? What we do is buy a lot of those cheap “Dupont” female-to-female cables, get the connections working and tested, and then tape them permanently together and label them. It’s not as pretty as a dedicated PCB adapter, but it’s quick and easy and gets you moving on to what you wanted to do in the first place.

Wrapup and Recommendations

The goal of connectors, and their standards, is putting parts together. If you’re designing a sensor module with more than a couple components, and you want it to be maximally easy for yourself and others to hook up to whatever mainboard they’ve got, this is no easy task. The end result is a proliferation of translators, adapter boards, hats, shields, capes, or whatever else. We have a drawer and a half full, and we bet you do too.

Yes, I do see what I’m suggesting here. [source: xkcd 927]
We’d be happy to see the world settle on Pmod for most needs, honestly, and we’d even throw away our beloved FTDI serial pinout in the name of standardization (or make an adapter). We can also see the need for exceptions like SVG / servo connectors when small sensors or multiples are in play. There will always be the need for dedicated on-board connectors as well, of course. Nobody said hardware was easy.

What’s your solution to the ultimate connector conundrum? Are there important connector systems that we’ve left out? What are their design tradeoffs? How stoked would you be if things could just plug together? Let us know!

Thumbnail image courtesy of [Raspberry Pi Controller].


Filed under: Engineering, Hackaday Columns, hardware, rants

Win a Jetduino robotics board for the JetsonTK1

I just launched a contest to give away 2 prototypes of the new Jetduino robotics interface board for the Jetson TK1. The Jetduino mounts on top of the TK1 and level shifts all of its GPIO, I2C, serial and SPI lines to 3.3V or 5v. It has Grove and 3-pin 2.54mm headers to make it very easy to connect commercial off-the-shelf sensors to the Jetson and communicate with them via Python or C++. It also has a built-in shield for any Mega or Uno form factor Arduino.

read more

Control DC motors with a Grove H-Bridge and DynamixShield

I just uploaded a new video tutorial on how to use the Grove dual H-Bridge module with the DynamixShield and an Arduino Due to control DC motors. 


read more

Video tutorial on using RobotGeek modules with the DynamixShield and Arduino Due

Arduino Heart Rate Monitor


Project Description


Heart Rate Monitors are very popular at the moment.
There is something very appealing about watching the pattern of your own heart beat. And once you see it, there is an unstoppable urge to try and control it. This simple project will allow you to visualize your heart beat, and will calculate your heart rate. Keep reading to learn how to create your very own heart rate monitor.


 

Parts Required:


Fritzing Sketch


 

 
 
 

Grove Base Shield to Module Connections


 


 

Arduino Sketch


 

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/* =================================================================================================
      Project: Arduino Heart rate monitor
       Author: Scott C
      Created: 21st April 2015
  Arduino IDE: 1.6.2
      Website: http://arduinobasics.blogspot.com/p/arduino-basics-projects-page.html
  Description: This is a simple sketch that uses a Grove Ear-clip Heart Rate sensor attached to an Arduino UNO,
               which sends heart rate data to the computer via Serial communication. You can see the raw data
               using the Serial monitor on the Arduino IDE, however, this sketch was specifically
               designed to interface with the matching Processing sketch for a much nicer graphical display.
               NO LIBRARIES REQUIRED.
=================================================================================================== */

#define Heart 2                            //Attach the Grove Ear-clip sensor to digital pin 2.
#define LED 4                              //Attach an LED to digital pin 4

boolean beat = false; /* This "beat" variable is used to control the timing of the Serial communication
                                           so that data is only sent when there is a "change" in digital readings. */

//==SETUP==========================================================================================
void setup() {
  Serial.begin(9600); //Initialise serial communication
  pinMode(Heart, INPUT); //Set digital pin 2 (heart rate sensor pin) as an INPUT
  pinMode(LED, OUTPUT); //Set digital pin 4 (LED) to an OUTPUT
}


//==LOOP============================================================================================
void loop() {
  if(digitalRead(Heart)>0){ //The heart rate sensor will trigger HIGH when there is a heart beat
    if<!beat){><span>//Only send data when it first discovers a heart beat - otherwise it will send a high value multiple times</span><br />      beat=<span>true</span>; <span>//By changing the beat variable to true, it stops further transmissions of the high signal</span><br />      <span>digitalWrite</span>(LED, <span>HIGH</span>); <span>//Turn the LED on </span><br />      <span><b>Serial</b></span>.<span>println</span>(1023); <span>//Send the high value to the computer via Serial communication.</span><br />    }<br />  } <span>else</span> { <span>//If the reading is LOW, </span><br />    <span>if</span>(beat){ <span>//and if this has just changed from HIGH to LOW (first low reading)</span><br />      beat=<span>false</span>; <span>//change the beat variable to false (to stop multiple transmissions)</span><br />      <span>digitalWrite</span>(LED, <span>LOW</span>); <span>//Turn the LED off.</span><br />      <span><b>Serial</b></span>.<span>println</span>(0); <span>//then send a low value to the computer via Serial communication.</span><br />    }<br />  }<br />}</pre> </td> </tr> </table></div></p> <br />  <br />   <br />  <br />  <p> <h4><a href="https://processing.org/download/?processing">Processing Sketch</a></h4> <br />  <div> <table> <tr> <td> <pre> 1<br /> 2<br /> 3<br /> 4<br /> 5<br /> 6<br /> 7<br /> 8<br /> 9<br /> 10<br /> 11<br /> 12<br /> 13<br /> 14<br /> 15<br /> 16<br /> 17<br /> 18<br /> 19<br /> 20<br /> 21<br /> 22<br /> 23<br /> 24<br /> 25<br /> 26<br /> 27<br /> 28<br /> 29<br /> 30<br /> 31<br /> 32<br /> 33<br /> 34<br /> 35<br /> 36<br /> 37<br /> 38<br /> 39<br /> 40<br /> 41<br /> 42<br /> 43<br /> 44<br /> 45<br /> 46<br /> 47<br /> 48<br /> 49<br /> 50<br /> 51<br /> 52<br /> 53<br /> 54<br /> 55<br /> 56<br /> 57<br /> 58<br /> 59<br /> 60<br /> 61<br /> 62<br /> 63<br /> 64<br /> 65<br /> 66<br /> 67<br /> 68<br /> 69<br /> 70<br /> 71<br /> 72<br /> 73<br /> 74<br /> 75<br /> 76<br /> 77<br /> 78<br /> 79<br /> 80<br /> 81<br /> 82<br /> 83<br /> 84<br /> 85<br /> 86<br /> 87<br /> 88<br /> 89<br /> 90<br /> 91<br /> 92<br /> 93<br /> 94<br /> 95<br /> 96<br /> 97<br /> 98<br /> 99<br />100<br />101<br />102<br />103<br />104<br />105<br />106<br />107<br />108<br />109<br />110<br />111<br />112<br />113<br />114<br />115<br />116<br />117<br />118<br />119<br />120<br />121<br />122<br />123<br />124<br />125<br />126<br />127<br />128<br />129<br />130<br />131<br />132<br />133<br />134<br />135<br />136<br />137<br />138<br />139<br />140<br />141<br />142<br />143<br />144<br />145<br />146<br />147<br />148<br />149<br />150<br />151<br />152<br />153<br />154<br />155<br />156<br />157<br />158<br />159<br />160<br />161<br />162<br />163<br />164<br />165<br />166<br />167<br />168<br />169<br />170<br />171<br />172<br />173<br />174<br />175<br />176<br />177<br />178<br />179<br />180<br />181<br />182<br />183<br />184<br />185<br />186<br />187<br />188<br />189<br />190<br />191<br />192<br />193<br />194<br />195<br />196<br />197<br />198<br />199<br />200<br />201<br />202<br />203<br />204<br />205<br />206<br />207<br />208<br />209<br />210<br />211<br />212<br />213<br />214<br /></pre> </td> <td> <pre><br /><span>/* =================================================================================================</span><br /><span>       Project: Arduino Heart rate monitor</span><br /><span>        Author: Scott C</span><br /><span>       Created: 21st April 2015</span><br /><span>Processing IDE: 2.2.1</span><br /><span>       Website: http://arduinobasics.blogspot.com/p/arduino-basics-projects-page.html</span><br /><span>   Description: A Grove Ear-clip heart rate sensor allows an Arduino UNO to sense your pulse.</span><br /><span>                The data obtained by the Arduino can then be sent to the computer via Serial communication</span><br /><span>                which is then displayed graphically using this Processing sketch.</span><br /><span>                </span><br /><span>=================================================================================================== */</span><br /><br /><span>import</span> processing.serial.*; <span>// Import the serial library to allow Serial communication with the Arduino</span><br /><br /><span>int</span> numOfRecs = 45; <span>// numOfRecs: The number of rectangles to display across the screen</span><br />Rectangle[] myRecs = <span>new</span> Rectangle[numOfRecs]; <span>// myRecs[]: Is the array of Rectangles. Rectangle is a custom class (programmed within this sketch)</span><br /><br />Serial myPort;                                         <br /><span>String</span> comPortString=<span>"0"</span>; <span>//comPortString: Is used to hold the string received from the Arduino</span><br /><span>float</span> arduinoValue = 0; <span>//arduinoValue: Is the float variable converted from comPortString</span><br /><span>boolean</span> beat = <span>false</span>; <span>// beat: Used to control for multiple high/low signals coming from the Arduino</span><br /><br /><span>int</span> totalTime = 0; <span>// totalTime: Is the variable used to identify the total time between beats</span><br /><span>int</span> lastTime = 0; <span>// lastTime: Is the variable used to remember when the last beat took place</span><br /><span>int</span> beatCounter = 0; <span>// beatCounter: Is used to keep track of the number of beats (in order to calculate the average BPM)</span><br /><span>int</span> totalBeats = 10; <span>// totalBeats: Tells the computer that we want to calculate the average BPM using 10 beats.</span><br /><span>int</span>[] BPM = <span>new</span> <span>int</span>[totalBeats]; <span>// BPM[]: Is the Beat Per Minute (BPM) array - to hold 10 BPM calculations</span><br /><span>int</span> sumBPM = 0; <span>// sumBPM: Is used to sum the BPM[] array values, and is then used to calculate the average BPM.</span><br /><span>int</span> avgBPM = 0; <span>// avgBPM: Is the variable used to hold the average BPM calculated value.</span><br /><br /><span>PFont</span> f, f2; <span>// f & f2 : Are font related variables. Used to store font properties. </span><br /><br /><br /><span>//==SETUP==============================================================================================</span><br /><span>void</span> <span><b>setup</b></span>(){<br />  <span>size</span>(<span>displayWidth</span>,<span>displayHeight</span>); <span>// Set the size of the display to match the monitor width and height</span><br />  <span>smooth</span>(); <span>// Draw all shapes with smooth edges.</span><br />  f = <span>createFont</span>(<span>"Arial"</span>,24); <span>// Initialise the "f" font variable - used for the "calibrating" text displayed at the beginning</span><br />  f2 = <span>createFont</span>(<span>"Arial"</span>,96); <span>// Initialise the "f2" font variable - used for the avgBPM display on screen</span><br />  <br />  <span>for</span>(<span>int</span> i=0; i<numOfRecs; i++){ <span>// Initialise the array of rectangles</span><br />    myRecs[i] = <span>new</span> Rectangle(i, numOfRecs);<br />  }<br />  <br />  <span>for</span>(<span>int</span> i=0; i<totalBeats; i++){ <span>// Initialise the BPM array</span><br />    BPM[i] = 0;<br />  }<br />  <br />  myPort = <span>new</span> Serial(<span>this</span>, Serial.<span>list</span>()[0], 9600); <span>// Start Serial communication with the Arduino using a baud rate of 9600</span><br />  myPort.bufferUntil(<span>'\n'</span>); <span>// Trigger a SerialEvent on new line</span><br />}<br /><br /><br /><span>//==DRAW==============================================================================================</span><br /><span>void</span> <span><b>draw</b></span>(){<br />  <span>background</span>(0); <span>// Set the background to BLACK (this clears the screen each time)</span><br />  drawRecs();                                           <span>// Method call to draw the rectangles on the screen</span><br />  drawBPM();                                            <span>// Method call to draw the avgBPM value to the top right of the screen</span><br />}<br /><br /><br /><span>//==drawRecs==========================================================================================</span><br /><span>void</span> drawRecs(){ <span>// This custom method will draw the rectangles on the screen </span><br />  myRecs[0].setSize(arduinoValue);                      <span>// Set the first rectangle to match arduinoValue; any positive value will start the animation.</span><br />  <span>for</span>(<span>int</span> i=numOfRecs-1; i>0; i--){ <span>// The loop counts backwards for coding efficiency - and is used to draw all of the rectangles to screen</span><br />    myRecs[i].setMult(i);                               <span>// setMulti creates the specific curve pattern. </span><br />    myRecs[i].setRed(avgBPM);                           <span>// The rectangles become more "Red" with higher avgBPM values</span><br />    myRecs[i].setSize(myRecs[i-1].getH());              <span>// The current rectangle size is determined by the height of the rectangle immediately to it's left</span><br />    <span>fill</span>(myRecs[i].getR(),myRecs[i].getG(), myRecs[i].getB()); <span>// Set the colour of this rectangle</span><br />    <span>rect</span>(myRecs[i].getX(), myRecs[i].getY(), myRecs[i].getW(), myRecs[i].getH()); <span>// Draw this rectangle</span><br />  }<br />}<br /><br /><br /><span>//==drawBPM===========================================================================================</span><br /><span>void</span> drawBPM(){ <span>// This custom method is used to calculate the avgBPM and draw it to screen.</span><br />  sumBPM = 0;                                           <span>// Reset the sumBPM variable</span><br />  avgBPM = 0;                                           <span>// Reset the avgBPM variable</span><br />  <span>boolean</span> calibrating = <span>false</span>; <span>// calibrating: this boolean variable is used to control when the avgBPM is displayed to screen</span><br />  <br />  <span>for</span>(<span>int</span> i=1; i<totalBeats; i++){<br />    sumBPM = sumBPM + BPM[i-1];                         <span>// Sum all of the BPM values in the BPM array.</span><br />    <span>if</span>(BPM[i-1]<1){ <span>// If any BPM values are equal to 0, then set the calibrating variable to true. </span><br />      calibrating = <span>true</span>; <span>// This will be used later to display "calibrating" on the screen.</span><br />    }<br />  }<br />  avgBPM = sumBPM/(totalBeats-1);                       <span>// Calculate the average BPM from all BPM values</span><br />                                                        <br />  <span>fill</span>(255); <span>// The text will be displayed as WHITE text</span><br />  <span>if</span>(calibrating){<br />    <span>textFont</span>(f);<br />    <span>text</span>(<span>"Calibrating"</span>, (4*<span>width</span>)/5, (<span>height</span>/5)); <span>// If the calibrating variable is TRUE, then display the word "Calibrating" on screen</span><br />    <span>fill</span>(0); <span>// Change the fill and stroke to black (0) so that other text is "hidden" while calibrating variable is TRUE</span><br />    <span>stroke</span>(0);<br />  } <span>else</span> {<br />    <span>textFont</span>(f2);<br />    <span>text</span>(avgBPM, (4*<span>width</span>)/5, (<span>height</span>/5)); <span>// If the calibrating variable is FALSE, then display the avgBPM variable on screen</span><br />    <span>stroke</span>(255); <span>// Change the stroke to white (255) to show the white line underlying the word BPM.</span><br />  }<br />  <br />   <span>textFont</span>(f);<br />   <span>text</span>(<span>"BPM"</span>, (82*<span>width</span>)/100, (<span>height</span>/11)); <span>// This will display the underlined word "BPM" when calibrating variable is FALSE.</span><br />   <span>line</span>((80*<span>width</span>)/100, (<span>height</span>/10),(88*<span>width</span>)/100, (<span>height</span>/10));<br />   <span>stroke</span>(0);<br />}<br /><br /><br /><span>//==serialEvent===========================================================================================</span><br /><span>void</span> serialEvent(Serial cPort){ <span>// This will be triggered every time a "new line" of data is received from the Arduino</span><br /> comPortString = cPort.readStringUntil(<span>'\n'</span>); <span>// Read this data into the comPortString variable.</span><br /> <span>if</span>(comPortString != <span>null</span>) { <span>// If the comPortString variable is not NULL then</span><br />   comPortString=<span>trim</span>(comPortString); <span>// trim any white space around the text.</span><br />   <span>int</span> i = <span>int</span>(<span>map</span>(<span>Integer</span>.<span>parseInt</span>(comPortString),1,1023,1,<span>height</span>)); <span>// convert the string to an integer, and map the value so that the rectangle will fit within the screen.</span><br />   arduinoValue = <span>float</span>(i); <span>// Convert the integer into a float value.</span><br />   <span>if</span> (!beat){<br />     <span>if</span>(arduinoValue>0){ <span>// When a beat is detected, the "trigger" method is called.</span><br />       trigger(<span>millis</span>()); <span>// millis() creates a timeStamp of when the beat occured.</span><br />       beat=<span>true</span>; <span>// The beat variable is changed to TRUE to register that a beat has been detected.</span><br />     }<br />   }<br />   <span>if</span> (arduinoValue<1){ <span>// When the Arduino value returns back to zero, we will need to change the beat status to FALSE.</span><br />     beat = <span>false</span>;<br />   }<br /> }<br />} <br /><br /><br /><span>//==trigger===========================================================================================</span><br /><span>void</span> trigger(<span>int</span> time){ <span>// This method is used to calculate the Beats per Minute (BPM) and to store the last 10 BPMs into the BPM[] array.</span><br />  totalTime = time - lastTime;                         <span>// totalTime = the current beat time minus the last time there was a beat.</span><br />  lastTime = time;                                     <span>// Set the lastTime variable to the current "time" for the next round of calculations.</span><br />  BPM[beatCounter] = 60000/totalTime;                  <span>// Calculate BPM from the totalTime. 60000 = 1 minute.</span><br />  beatCounter++;                                       <span>// Increment the beatCounter </span><br />  <span>if</span> (beatCounter>totalBeats-1){ <span>// Reset the beatCounter when the total number of BPMs have been stored into the BPM[] array.</span><br />    beatCounter=0;                                     <span>// This allows us to keep the last 10 BPM calculations at all times.</span><br />  }<br />}<br /><br /><br /><span>//==sketchFullScreen==========================================================================================</span><br /><span>boolean</span> sketchFullScreen() { <span>// This puts Processing into Full Screen Mode</span><br /> <span>return</span> <span>true</span>;<br />}<br /><br /><br /><span>//==Rectangle CLASS==================================================================================*********</span><br /><span>class</span> Rectangle{<br />  <span>float</span> xPos, defaultY, yPos, myWidth, myHeight, myMultiplier; <span>// Variables used for drawing rectangles</span><br />  <span>int</span> blueVal, greenVal, redVal; <span>// Variables used for the rectangle colour</span><br />  <br />  Rectangle(<span>int</span> recNum, <span>int</span> nRecs){ <span>// The rectangles are constructed using two variables. The total number of rectangles to be displayed, and the identification of this rectangle (recNum)</span><br />    myWidth = <span>displayWidth</span>/nRecs; <span>// The width of the rectangle is determined by the screen width and the total number of rectangles.</span><br />    xPos = recNum * myWidth;                                      <span>// The x Position of this rectangle is determined by the width of the rectangles (all same) and the rectangle identifier.</span><br />    defaultY=<span>displayHeight</span>/2; <span>// The default Y position of the rectangle is half way down the screen.</span><br />    yPos = defaultY;                                              <span>// yPos is used to adjust the position of the rectangle as the size changes.</span><br />    myHeight = 1;                                                 <span>// The height of the rectangle starts at 1 pixel</span><br />    myMultiplier = 1;                                             <span>// The myMultiplier variable will be used to create the funnel shaped path for the rectangles.</span><br />    redVal = 0;                                                   <span>// The red Value starts off being 0 - but changes with avgBPM. Higher avgBPM means higher redVal</span><br />    <br />    <span>if</span> (recNum>0){ <span>// The blue Value progressively increases with every rectangle (moving to the right of the screen)</span><br />      blueVal = (recNum*255)/nRecs;<br />    } <span>else</span> {<br />      blueVal = 0;<br />    }<br />    greenVal = 255-blueVal;                                       <span>// Initially, the green value is at the opposite end of the spectrum to the blue value.</span><br />  }<br />  <br />  <span>void</span> setSize(<span>float</span> newSize){ <span>// This is used to set the new size of each rectangle </span><br />    myHeight=newSize*myMultiplier;<br />    yPos=defaultY-(newSize/2);<br />  }<br />  <br />  <span>void</span> setMult(<span>int</span> i){ <span>// The multiplier is a function of COS, which means that it varies from 1 to 0.</span><br />    myMultiplier = <span>cos</span>(<span>radians</span>(i)); <span>// You can try other functions to experience different effects.</span><br />  }<br />  <br />  <span>void</span> setRed(<span>int</span> r){<br />    redVal = <span>int</span>(<span>constrain</span>(<span>map</span>(<span>float</span>(r), 60, 100, 0, 255),0,255)); <span>// setRed is used to change the redValue based on the "normal" value for resting BPM (60-100). </span><br />    greenVal = 255 - redVal;                                       <span>// When the avgBPM > 100, redVal will equal 255, and the greenVal will equal 0.</span><br />  }                                                                <span>// When the avgBPM < 60, redVal will equal 0, and greenVal will equal 255.</span><br />  <br />  <span>float</span> getX(){ <span>// get the x Position of the rectangle</span><br />    <span>return</span> xPos;<br />  }<br /> <br />  <span>float</span> getY(){ <span>// get the y Position of the rectangle</span><br />    <span>return</span> yPos;<br />  }<br />  <br />  <span>float</span> getW(){ <span>// get the width of the rectangle</span><br />    <span>return</span> myWidth;<br />  }<br />  <br />  <span>float</span> getH(){ <span>// get the height of the rectangle</span><br />    <span>return</span> myHeight;<br />  }<br />  <br />  <span>float</span> getM(){ <span>// get the Multiplier of the rectangle</span><br />    <span>return</span> myMultiplier;<br />  }<br />  <br />  <span>int</span> getB(){ <span>// get the "blue" component of the rectangle colour</span><br />    <span>return</span> blueVal;<br />  }<br />  <br />  <span>int</span> getR(){ <span>// get the "red" component of the rectangle colour</span><br />    <span>return</span> redVal;<br />  }<br />  <br />  <span>int</span> getG(){ <span>// get the "green" component of the rectangle colour</span><br />    <span>return</span> greenVal;<br />  }<br />}<br /><br /></pre> </td> </tr> </table></div></p> <br />  <br /> <p> <h4>Processing Code Discussion:</h4><br /> </p><p> The Rectangle class was created to store relevant information about each rectangle. By using a custom class, we were able to design our rectangles any way we wanted. These rectangles have properties and methods which allow us to easily control their position, size and colour. By adding some smart functionality to each rectangle, we were able to get the rectangle to automatically position and colour itself based on key values. </p> <p> The Serial library is used to allow communication with the Arduino. In this Processing sketch, the values obtained from the Arduino were converted to floats to allow easy calulations of the beats per minute (BPM). I am aware that I have over-engineered the serialEvent method somewhat, because the Arduino is only really sending two values. I didn't really need to convert the String. But I am happy with the end result, and it does the job I needed it to... </p> <div> <p> <div> <a href="http://4.bp.blogspot.com/-EVTCQ3vkgGc/VTnOarlOWSI/AAAAAAAABdc/MslEU5oirAY/s1600/Complete%2BWorkstation2.jpg"><img src="http://4.bp.blogspot.com/-EVTCQ3vkgGc/VTnOarlOWSI/AAAAAAAABdc/MslEU5oirAY/s1600/Complete%2BWorkstation2.jpg" /> </a> </div> </p> </div> </div><!--separator --><img src="https://images-blogger-opensocial.googleusercontent.com/gadgets/proxy?url=http%3A%2F%2F1.bp.blogspot.com%2F-XQiwNpdqOxk%2FT_rKCzDh4nI%2FAAAAAAAAAQY%2FOfYBljhU6Lk%2Fs1600%2FSeparator.jpg&container=blogger&gadget=a&rewriteMime=image%2F*" /><br /><p> <div> This project is quite simple. I designed it so that you could omit the Processing code if you wanted to. In that scenario, you would only be left with a blinking LED that blinks in time with your pulse. The Processing code takes this project to the next level. It provides a nice animation and calculates the beats per minute (BPM). <br />   <br /> I hope you liked this tutorial. Please feel free to share it, comment or give it a plus one. If you didn't like it, I would still appreciate your constructive feedback. </div> <br />  <div> <p> <!--separator --> <img src="https://images-blogger-opensocial.googleusercontent.com/gadgets/proxy?url=http%3A%2F%2F1.bp.blogspot.com%2F-XQiwNpdqOxk%2FT_rKCzDh4nI%2FAAAAAAAAAQY%2FOfYBljhU6Lk%2Fs1600%2FSeparator.jpg&container=blogger&gadget=a&rewriteMime=image%2F*" /><br /> <br /> </p> </div> </p><p> <div> If you like this page, please do me a favour and show your appreciation : <br /> <br />  <br /> Visit my <a href="https://plus.google.com/u/0/b/107402020974762902161/107402020974762902161/posts">ArduinoBasics Google + page</a>.<br /> Follow me on Twitter by looking for <a href="https://twitter.com/ArduinoBasics">ScottC @ArduinoBasics</a>.<br /> I can also be found on <a href="https://www.pinterest.com/ArduinoBasics/">Pinterest</a> and <a href="https://instagram.com/arduinobasics">Instagram</a>. <br /> Have a look at my videos on my <a href="https://www.youtube.com/user/ScottCMe/videos">YouTube channel</a>.<br /> </div> </p> <br />  <br />  <p> <div> <a href="http://3.bp.blogspot.com/-x_TA-qhOCzM/VTnULXoWhQI/AAAAAAAABds/quh02BWGsec/s1600/Slide1.JPG"><img src="http://3.bp.blogspot.com/-x_TA-qhOCzM/VTnULXoWhQI/AAAAAAAABds/quh02BWGsec/s1600/Slide1.JPG" /></a></div><br /> </p> <br />  <br />  <br />  <div> <p> <!--separator --> <img src="https://images-blogger-opensocial.googleusercontent.com/gadgets/proxy?url=http%3A%2F%2F1.bp.blogspot.com%2F-XQiwNpdqOxk%2FT_rKCzDh4nI%2FAAAAAAAAAQY%2FOfYBljhU6Lk%2Fs1600%2FSeparator.jpg&container=blogger&gadget=a&rewriteMime=image%2F*" /><br /> <br /> </p> </div> <p> However, if you do not have a google profile... <br />Feel free to share this page with your friends in any way you see fit. </p>

Arduino BeatBox

Create your very own Arduino BeatBox !

Home-made capacitive touch sensors are used to trigger the MP3 drum sounds stored on the Grove Serial MP3 player. I have used a number of tricks to get the most out of this module, and I was quite impressed on how well it did. Over 130 sounds were loaded onto the SDHC card. Most were drum sounds, but I added some farm animal noises to provide an extra element of surprise and entertainment. You can put any sounds you want on the module and play them back quickly. We'll put the Grove Serial MP3 module through it's paces and make it into a neat little BeatBox !!


Key learning objectives

  • How to make your own beatbox
  • How to make capacitive drum pad sensors without using resistors
  • How to speed up Arduino's Analog readings for better performance
  • How to generate random numbers on your Arduino


Parts Required:

Making the drum pads


 
 

Fritzing Sketch


 


 
 

Grove Connections


 


 
 

Grove Connections (without base shield)


 


 
 

Arduino Sketch


 
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/* =================================================================================================
      Project: Arduino Beatbox
       Author: Scott C
      Created: 9th April 2015
  Arduino IDE: 1.6.2
      Website: http://arduinobasics.blogspot.com/p/arduino-basics-projects-page.html
  Description: This project uses home made capacitive sensors to trigger over 130 MP3 sounds
               on the Grove Serial MP3 player. 
               
               The ADCTouch library is used to eliminate the resistors from the Capacitive sensing circuit. 
               The code used for capacitive sensing was adapted from the ADCTouch library example sketches. 
               You can find the ADCTouch library and relevant example code here:
               http://playground.arduino.cc/Code/ADCTouch
               
               "Advanced Arduino ADC" is used to improve the analogRead() speed, and enhance the
               drum pad or capacitive sensor response time. The Advanced Arduino ADC code 
               was adapted from this site:
               http://www.microsmart.co.za/technical/2014/03/01/advanced-arduino-adc/
               
               
=================================================================================================== */
  #include <ADCTouch.h>
  #include <SoftwareSerial.h>
  
  
  //Global variables
  //===================================================================================================
  int potPin = A4; //Grove Sliding potentiometer is connected to Analog Pin 4
  int potVal = 0;
  byte mp3Vol = 0; //Variable used to control the volume of the MP3 player
  byte oldVol = 0;
  
  int buttonPin = 5; //Grove Button is connected to Digital Pin 5
  int buttonStatus = 0;
  
  byte SongNum[4] = {0x01,0x02,0x03,0x04}; //The first 4 songs will be assigned to the drum pads upon initialisation
  byte numOfSongs = 130; //Total number of MP3 songs/sounds loaded onto the SDHC card
  
  long randNumber; //Variable used to hold the random number - used to randomise the sounds.
  
  int ledState[4]; //Used to keep track of the status of all LEDs (on or off)
  int counter = 0;
  
  SoftwareSerial mp3(3, 4); // The Grove MP3 Player is connected to Arduino digital Pin 3 and 4 (Serial communication)
       
  int ref0, ref1, ref2, ref3; //reference values to remove offset
  int threshold = 100;
      
  // Define the ADC prescalers
  const unsigned char PS_64 = (1 << ADPS2) | (1 << ADPS1);
  const unsigned char PS_128 = (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0);
  
  
  
  //Setup()
  //===================================================================================================
  void setup(){
    //Initialise the Grove MP3 Module
    delay(2500); //Allow the MP3 module to power up
    mp3.begin(9600); //Begin Serial communication with the MP3 module
    setPlayMode(0x00);                        //0x00 = Single song - played once ie. not repeated. (default)
    
    //Define the Grove Button as an INPUT
    pinMode(buttonPin, INPUT);
    
    //Define the 4 LED Pins as OUTPUTs
    pinMode(8, OUTPUT); //Green LED
    pinMode(9, OUTPUT); //Blue LED
    pinMode(10, OUTPUT); //Red LED
    pinMode(11, OUTPUT); //Yellow LED
    
    //Make sure each LED is OFF, and store the state of the LED into a variable.
    for(int i=8;i<12;i++){
      digitalWrite(i, LOW);
      ledState[i-8]=0;
    } 
    
    //Double our clock speed from 125 kHz to 250 kHz
    ADCSRA &= ~PS_128;   // set up the ADC
    ADCSRA |= PS_64;    // set our own prescaler to 64
    
    //Create reference values to account for the capacitance of each pad.
    ref0 = ADCTouch.read(A0, 500);
    ref1 = ADCTouch.read(A1, 500); //Take 500 readings
    ref2 = ADCTouch.read(A2, 500);
    ref3 = ADCTouch.read(A3, 500);
    
     //This helps to randomise the drum pads.
     randomSeed(analogRead(0));
  }
  
  
  
  // Loop()
  //===================================================================================================
  void loop(){
     
    //Take a reading from the Grove Sliding Potentiometer, and set volume accordingly
    potVal = analogRead(potPin);
    mp3Vol = map(potVal, 0, 1023, 0,31); // Convert the potentometer reading (0 - 1023) to fit within the MP3 player's Volume range (0 - 31)
    if((mp3Vol>(oldVol+1))|(mp3Vol<(oldVol-1))){ // Only make a change to the Volume on the Grove MP3 player when the potentiometer value changes
      oldVol = mp3Vol;
      setVolume(mp3Vol);
      delay(10); // This delay is necessary with Serial communication to MP3 player
    }
    
    //Take a reading from the Pin attached to the Grove Button. If pressed, randomise the MP3 songs/sounds for each drum pad, and make the LEDs blink randomly.
    buttonStatus = digitalRead(buttonPin);
    if(buttonStatus==HIGH){
      SongNum[0]=randomSongChooser(1, 30);
      SongNum[1]=randomSongChooser(31, 60);
      SongNum[2]=randomSongChooser(61, 86);
      SongNum[3]=randomSongChooser(87, (int)numOfSongs);
      randomLEDBlink();
    }
    
    //Get the capacitive readings from each drum pad: 50 readings are taken from each pad. (default is 100)
    int value0 = ADCTouch.read(A0,50); // Green drum pad
    int value1 = ADCTouch.read(A1,50); // Blue drum pad
    int value2 = ADCTouch.read(A2,50); // Red drum pad
    int value3 = ADCTouch.read(A3,50); // Yellow drum pad
    
    //Remove the offset to account for the baseline capacitance of each pad.
    value0 -= ref0;       
    value1 -= ref1;
    value2 -= ref2;
    value3 -= ref3;
    
    
    //If any of the values exceed the designated threshold, then play the song/sound associated with that drum pad.
    //The associated LED will stay on for the whole time the drum pad is pressed, providing the value remains above the threshold.
    //The LED will turn off when the pad is not being touched or pressed.
    if(value0>threshold){
      digitalWrite(8, HIGH);
      playSong(00,SongNum[0]);
    }else{
      digitalWrite(8,LOW);
    }
    
    if(value1>threshold){
      digitalWrite(9, HIGH);
      playSong(00,SongNum[1]);
    }else{
      digitalWrite(9,LOW);
    }
    
    if(value2>threshold){
      digitalWrite(10, HIGH);
      playSong(00,SongNum[2]);
    }else{
      digitalWrite(10,LOW);
    }
    
    if(value3>threshold){
      digitalWrite(11, HIGH);
      playSong(00,SongNum[3]);
    }else{
      digitalWrite(11,LOW);
    }
  }
      
   
  // writeToMP3:
  // a generic function that simplifies each of the methods used to control the Grove MP3 Player
  //===================================================================================================
  void writeToMP3(byte MsgLEN, byte A, byte B, byte C, byte D, byte E, byte F){
    byte codeMsg[] = {MsgLEN, A,B,C,D,E,F};
    mp3.write(0x7E); //Start Code for every command = 0x7E
    for(byte i = 0; i<MsgLEN+1; i++){
      mp3.write(codeMsg[i]); //Send the rest of the command to the GROVE MP3 player
    }
  }
  
  
  //setPlayMode: defines how each song is to be played
  //===================================================================================================
  void setPlayMode(byte playMode){
    /* playMode options:
          0x00 = Single song - played only once ie. not repeated.  (default)
          0x01 = Single song - cycled ie. repeats over and over.
          0x02 = All songs - cycled 
          0x03 = play songs randomly                                           */
    writeToMP3(0x03, 0xA9, playMode, 0x7E, 0x00, 0x00, 0x00);  
  }
  
  
  //playSong: tells the Grove MP3 player to play the song/sound, and also which song/sound to play
  //===================================================================================================
  void playSong(byte songHbyte, byte songLbyte){
    writeToMP3(0x04, 0xA0, songHbyte, songLbyte, 0x7E, 0x00, 0x00);            
    delay(100);
  }
  
  
  //setVolume: changes the Grove MP3 player's volume to the designated level (0 to 31)
  //===================================================================================================
  void setVolume(byte Volume){
    byte tempVol = constrain(Volume, 0, 31); //Volume range = 00 (muted) to 31 (max volume)
    writeToMP3(0x03, 0xA7, tempVol, 0x7E, 0x00, 0x00, 0x00); 
  }
  
  
  //randomSongChooser: chooses a random song to play. The range of songs to choose from
  //is limited and defined by the startSong and endSong parameters.
  //===================================================================================================
  byte randomSongChooser(int startSong, int endSong){
    randNumber = random(startSong, endSong);
    return((byte) randNumber);
  }
  
  
  //randomLEDBlink: makes each LED blink randomly. The LEDs are attached to digital pins 8 to 12.
  //===================================================================================================
  void randomLEDBlink(){
   counter=8;
   for(int i=0; i<40; i++){
     int x = constrain((int)random(8,12),8,12);
     toggleLED(x);
     delay(random(50,100-i));
   }
     
    for(int i=8;i<12;i++){
      digitalWrite(i, HIGH);
    }
    delay(1000);
    for(int i=8;i<12;i++){
      digitalWrite(i, LOW);
      ledState[i-8]=0;
    }
  }
  
  
  //toggleLED: is used by the randomLEDBlink method to turn each LED on and off (randomly).
  //===================================================================================================
  void toggleLED(int pinNum){
    ledState[pinNum-8]= !ledState[pinNum-8];
    digitalWrite(pinNum, ledState[pinNum-8]);
  }


 

Arduino Code Discussion

You can see from the Arduino code above, that it uses the ADCTouch library. This library was chosen over the Capacitive Sensing Library to eliminate the need for a high value resistor which are commonly found in Capacitive Sensing projects).
 
To increase the speed of the Analog readings, I utilised one of the "Advanced Arduino ADC" techniques described by Guy van den Berg on this Microsmart website.
 
The readings are increased by modifying the Arduino's ADC clock speed from 125kHz to 250 kHz. I did notice an overall better response time with this modification. However, the Grove Serial MP3 player is limited by it's inability to play more than one song or sound at a time. This means that if you hit another drum pad while the current sound is playing, it will stop playing the current sound, and then play the selected sound. The speed at which it can perform this task was quite impressive. In fact it was much better than I thought it would be. But if you are looking for polyphonic playability, you will be dissapointed.
 
This Serial MP3 module makes use of a high quality MP3 audio chip known as the "WT5001". Therefore, you should be able to get some additional features and functionality from this document. Plus you may find some extra useful info from the Seeedstudio wiki. I have re-used some code from the Arduino Boombox tutorial... you will find extra Grove Serial MP3 functions on that page.
 
I will warn you... the Grove Serial MP3 player can play WAV files, however for some reason it would not play many of the sound files in this format. Once the sounds were converted to the MP3 format, I did not look back. So if you decide to take on this project, make sure your sound files are in MP3 format, you'll have a much better outcome.
 
I decided to introduce a random sound selection for each drum pad to extend the novelty of this instrument, which meant that I had to come up with a fancy way to illuminate the LEDs. I demonstrated some of my other LED sequences on my instagram account. I sometimes use instagram to show my work in progress.
 
Have a look at the video below to see this project in action, and putting the Grove Serial MP3 player through it's paces.
 

The Video


 


First there was the Arduino Boombox, and now we have the Arduino Beatbox..... who knows what will come next !
 
Whenever I create a new project, I like to improve my Arduino knowledge. Sometimes it takes me into some rather complicated topics. There is a lot I do not know about Arduino, but I am enjoying the journey. I hope you are too !! Please Google plus one this post if it helped you in any way. These tutorials are free, which means I survive on feedback and plus ones... all you have to do is just scroll a little bit more and click that button :)

 
 



If you like this page, please do me a favour and show your appreciation :

 
Visit my ArduinoBasics Google + page.
Follow me on Twitter by looking for ScottC @ArduinoBasics.
I can also be found on Pinterest and Instagram.
Have a look at my videos on my YouTube channel.


 
 

 
 
 



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Feel free to share this page with your friends in any way you see fit.

Arduino Boombox

Add sound or music to your project using the "Grove Serial MP3 Player".

An Arduino UNO will be used to control the Grove Serial MP3 player by sending it specific serial commands. The Grove Base Shield allows for the easy connection of Grove sensor modules to an Arduino UNO without the need for a breadboard. A sliding potentiometer, switch and button will be connected to the Base shield along with the Serial MP3 player. A specific function will be assigned to each of the connected sensor modules to provide a useful interface:

  • Sliding Potentiometer – Volume control
  • Button – Next Song
  • Switch – On/Off (toggle)
Once the MP3 module is working the way we want, we can then build a simple enclosure for it. Grab a shoe-box, print out your favourite design, and make your very own Arduino BOOMBOX!


 

Video

Watch the following video to see the project in action
 


 
 

Parts Required:

Optional components (for the BoomBox Enclosure):
  • Empty Shoe Box
  • Paper
  • Printer
  • Glue
If I had a 3D printer - I would have printed my own enclosure, but a shoebox seems to work just fine.


 

Putting it Together

Place the Grove Base shield onto the Arduino UNO,
and then connect each of the Grove Modules as per the table below.
 


 

If you do not have a Grove Base shield,
you can still connect the modules directly to the Arduino as per the table below:
 


 

When you are finished connecting the modules, it should look something like this:
  (ignore the battery pack):
 

As you can see from the picture above. You can cut holes out of the shoebox and stick the modules in place. Please ignore the battery pack, because you won't use it until after you have uploaded the Arduino code.


 
 

Arduino Sketch


 
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/* ===============================================================================
      Project: Grove Serial MP3 Player overview
       Author: Scott C
      Created: 9th March 2015
  Arduino IDE: 1.6.0
      Website: http://arduinobasics.blogspot.com/p/arduino-basics-projects-page.html

  Description: The following Arduino sketch will allow you to control a Grove Serial MP3 player
               with a Grove Sliding Potentiometer (volume), a Grove button (next song), 
               and a Grove Switch (on/off). It will also show you how to retrieve some useful information from the player. 
               Some functions are not used in this sketch,but have been included for your benefit. 
               
               Additional features and functionality can be found on the WT5001 voice chip datasheet 
               which I retrieved from here: http://goo.gl/ai6oQ9
               
               The Seeedstudio wiki was a very useful resource for getting started with the various Grove modules:
               http://goo.gl/xOiSCl
=============================================================================== */

#include <SoftwareSerial.h>
SoftwareSerial mp3(2, 3); // The Grove MP3 Player is connected to Arduino digital Pin 2 and 3 (Serial communication)
int potPin = A0; // The Sliding Potentiometer is connected to AnalogPin 0
int potVal = 0; // This is used to hold the value of the Sliding Potentiometer
byte mp3Vol = 0; // mp3Vol is used to calculate the Current volume of the Grove MP3 player
byte oldVol = 0; // oldVol is used to remember the previous volume level
int ledPin = A1; // The Grove sliding potentiometer has an onboard LED attached to Analog pin 1.

int switchPin = 12; // The Grove Switch(P) is connected to digital Pin 12
int switchStatus = 0; // This is used to hold the status of the switch
int switchChangeStatus = 0; // Used to identify when the switch status has changed

int buttonPin = 5; // The Grove Button is connected to digital pin 5
int buttonStatus = 0; // This is used to hold the status of the button



void setup(){
  //Initialise the Grove MP3 Module
  delay(2500);
  mp3.begin(9600);
  
        
  // initialize the pushbutton and switch pin as an input:
  pinMode(buttonPin, INPUT);
  pinMode(switchPin, INPUT);
  
  // set ledPin on the sliding potentiometer to OUTPUT
  pinMode(ledPin, OUTPUT);
  
  //You can view the following demostration output in the Serial Monitor
  demonstrate_GET_FUNCTIONS();     
}


void loop(){
  switchStatus = digitalRead(switchPin);
  if(switchStatus==HIGH){
    if(switchChangeStatus==LOW){ // When Arduino detects a change in the switchStatus (from LOW to HIGH) - play song
      setPlayMode(0x02);                     // Automatically cycle to the next song when the current song ends
      playSong(00,01);                       // Play the 1st song when you switch it on
      switchChangeStatus=HIGH;
    }
    
    potVal = analogRead(potPin); // Analog read values from the sliding potentiometer range from 0 to 1023
    analogWrite(ledPin, potVal/4); // Analog write values range from 0 to 255, and will turn LED ON once potentiometer reaches about half way (or more).
    mp3Vol = map(potVal, 0, 1023, 0,31); // Convert the potentometer reading (0 - 1023) to fit within the MP3 player's Volume range (0 - 31)
    if((mp3Vol>(oldVol+1))|(mp3Vol<(oldVol-1))){ // Only make a change to the Volume on the Grove MP3 player when the potentiometer value changes
      oldVol = mp3Vol;
      setVolume(mp3Vol);
      delay(10); // This delay is necessary with Serial communication to MP3 player
    }

    buttonStatus = digitalRead(buttonPin);
    if(buttonStatus==HIGH){ // When a button press is detected - play the next song
      playNextSong();
      delay(200); // This delay aims to prevent a "skipped" song due to slow button presses - can modify to suit.
    }
  } else {
    if(switchChangeStatus==HIGH){ // When switchStatus changes from HIGH to LOW - stop Song.
      stopSong();
      switchChangeStatus=LOW;
    }
  } 
}


// demonstrate_GET_FUNCTIONS  will show you how to retrieve some useful information from the Grove MP3 Player (using the Serial Monitor).
void demonstrate_GET_FUNCTIONS(){
        Serial.begin(9600);
        Serial.print("Volume: ");
        Serial.println(getVolume());
        Serial.print("Playing State: ");
        Serial.println(getPlayingState());
        Serial.print("# of Files in SD Card:");
        Serial.println(getNumberOfFiles());
        Serial.println("------------------------------");
}


// writeToMP3: is a generic function that aims to simplify all of the methods that control the Grove MP3 Player

void writeToMP3(byte MsgLEN, byte A, byte B, byte C, byte D, byte E, byte F){
  byte codeMsg[] = {MsgLEN, A,B,C,D,E,F};
  mp3.write(0x7E); //Start Code for every command = 0x7E
  for(byte i = 0; i<MsgLEN+1; i++){
    mp3.write(codeMsg[i]); //Send the rest of the command to the GROVE MP3 player
  }
}


/* The Following functions control the Grove MP3 Player : see datasheet for additional functions--------------------------------------------*/

void setPlayMode(byte playMode){
  /* playMode options:
        0x00 = Single song - played only once ie. not repeated.  (default)
        0x01 = Single song - cycled ie. repeats over and over.
        0x02 = All songs - cycled 
        0x03 = play songs randomly                                           */
        
  writeToMP3(0x03, 0xA9, playMode, 0x7E, 0x00, 0x00, 0x00);  
}


void playSong(byte songHbyte, byte songLbyte){ // Plays the selected song
  writeToMP3(0x04, 0xA0, songHbyte, songLbyte, 0x7E, 0x00, 0x00);            
}


void pauseSong(){ // Pauses the current song
  writeToMP3(0x02, 0xA3, 0x7E, 0x00, 0x00, 0x00, 0x00);
}


void stopSong(){ // Stops the current song
  writeToMP3(0x02, 0xA4, 0x7E, 0x00, 0x00, 0x00, 0x00);
}


void playNextSong(){ // Play the next song
  writeToMP3(0x02, 0xA5, 0x7E, 0x00, 0x00, 0x00, 0x00);
}


void playPreviousSong(){ // Play the previous song
  writeToMP3(0x02, 0xA6, 0x7E, 0x00, 0x00, 0x00, 0x00);
}


void addSongToPlayList(byte songHbyte, byte songLbyte){
  //Repeat this function for every song you wish to stack onto the playlist (max = 10 songs)
  writeToMP3(0x04, 0xA8, songHbyte, songLbyte, 0x7E, 0x00, 0x00);
}


void setVolume(byte Volume){ // Set the volume
  byte tempVol = constrain(Volume, 0, 31);
  //Volume range = 00 (muted) to 31 (max volume)
  writeToMP3(0x03, 0xA7, tempVol, 0x7E, 0x00, 0x00, 0x00); 
}



/* The following functions retrieve information from the Grove MP3 player : see data sheet for additional functions--------------*/

// getData: is a generic function to simplifly the other functions for retieving information from the Grove Serial MP3 player
byte getData(byte queryVal, int dataPosition){
  byte returnVal = 0x00;
  writeToMP3(0x02, queryVal, 0x7E, 0x00, 0x00, 0x00, 0x00);
  delay(50);
  for(int x = 0; x<dataPosition; x++){
    if(mp3.available()){
      returnVal = mp3.read();
      delay(50);
    }
  }
  return(returnVal);
}

byte getVolume(){ //Get the volume of the Grove Serial MP3 player
  //returns value from 0 - 31
  return(getData(0xC1, 4));
}

byte getPlayingState(){ //Get the playing state : Play / Stopped / Paused
  //returns 1: Play, 2: Stop, 3:Paused
  return(getData(0xC2, 2));
}


byte getNumberOfFiles(){ //Find out how many songs are on the SD card
  //returns the number of MP3 files on SD card
  return(getData(0xC4, 3));
}

You will notice from the code, that I did not utilise every function. I decided to include them for your benifit. This Serial MP3 module makes use of a high quality MP3 audio chip known as the "WT5001". Therefore, you should be able to get some additional features and functionality from this document. Plus you may find some extra useful info from the Seeedstudio wiki.
 
IMPORTANT: You need to load your MP3 sounds or songs onto the SDHC card before you install it onto the Serial MP3 player.
 
Once the SDHC card is installed, and your code is uploaded to the Arduino, all you have to do now is connect the MP3 player to some headphones or a powered speaker. You can then power the Arduino and modules with a battery pack or some other portable power supply.
 
You can design and decorate the shoebox in any way you like. Just print out your picture, glue them on, and before you know it, you will have your very own Arduino Boombox.
 


Comments

I was very surprised by the quality of the sound that came from the MP3 module. It is actually quite good.

This tutorial was an introduction to the Grove Serial MP3 module in it's most basic form. You could just as easily use some other sensor to trigger the MP3 module. For example, you could get it to play an alert if a water leak was detected, or if a door was opened, or if the temperature got too high or too low. You could get it to play a reminder when you walk into your room. The possibilities are endless.

I really liked this module, and I am sure it will appear in a future tutorial.


 



If you like this page, please do me a favour and show your appreciation :

 
Visit my ArduinoBasics Google + page.
Follow me on Twitter by looking for ScottC @ArduinoBasics.
I can also be found on Pinterest and Instagram.
Have a look at my videos on my YouTube channel.


 
 

 
 
 



However, if you do not have a google profile...
Feel free to share this page with your friends in any way you see fit.

Grove Water Sensor


Connecting a water sensor to an Arduino is a great way to detect a leak, spill, flood, rain etc. It can be used to detect the presence, level, volume and/or the absence of water. While this could be used to remind you to water your plants, there is a better Grove sensor for that. The sensor has an array of exposed traces which will read LOW when water is detected. In this tutorial, we will connect the Water Sensor to Digital Pin 8 on the Arduino, and will enlist the very handy Grove Piezo buzzer and an LED to help identify when the Water sensor comes into contact with a source of water.


 

Parts Required:

Putting it together


If you have a Grove Base Shield, you just have to connect the Grove Water Sensor to D8 on the shield, and the Buzzer to D12 on the Shield. My Grove base shield obstructs the onboard LED, so I will attach an LED to Digital pin 13. If you do not have a Grove base shield, then you should connect the Sensors as described in the tables below:
 


 

Arduino Sketch


 
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/* 
  Grove Water Sensor sketch 
     Written by ScottC 5th August 2014
     Arduino IDE version 1.0.5
     Website: http://arduinobasics.blogspot.com
     Description: Use Grove Water Sensor to detect leaks, floods, spills, rain etc.
     Credits: This sketch was inspired by this website:
              http://www.seeedstudio.com/wiki/Grove_-_Water_Sensor     
 ------------------------------------------------------------- */
#define Grove_Water_Sensor 8     //Attach Water sensor to Arduino Digital Pin 8
#define Grove_Piezo_Buzzer 12    //Attach Piezo Buzzer to Arduino Digital Pin 12
#define LED 13                   //Attach an LED to Digital Pin 13 (or use onboard LED)
void setup(){
pinMode(Grove_Water_Sensor, INPUT); //The Water Sensor is an Input
pinMode(Grove_Piezo_Buzzer, OUTPUT); //The Piezo Buzzer is an Output
        pinMode(LED, OUTPUT); //The LED is an Output
}

void loop(){
        /* The water sensor will switch LOW when water is detected.
           Get the Arduino to illuminate the LED and activate the buzzer
           when water is detected, and switch both off when no water is present */
if(digitalRead(Grove_Water_Sensor) == LOW){
                digitalWrite(LED,HIGH);
digitalWrite(Grove_Piezo_Buzzer, HIGH);
                delay(2);
                digitalWrite(Grove_Piezo_Buzzer, LOW);
                delay(40);
        }else{
                digitalWrite(Grove_Piezo_Buzzer, LOW);
                digitalWrite(LED,LOW);
        }
}


 

The Video


 


If you liked this tutorial - please show your support :

ScottC 05 Aug 16:38

Grove Button Tutorial

The Grove Button is a handy little component which simplifies the push-button experience. It doesn't take much programming to get this component to work. And while the button works extremely well with the Grove Base Shield, we will be connecting this button directly to the Arduino UNO.

The button will be LOW in its normal resting state, and report HIGH when the button is pressed. Have a look at the video below to see this project in action.

Video






Parts Required




Sketch







Arduino Sketch




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/* Grove Button Sketch - Written by ScottC 22nd Dec 2013 
http://arduinobasics.blogspot.com
--------------------------------------------------------- */

void setup(){
pinMode(8, INPUT);
pinMode(13, OUTPUT);
}

void loop(){
digitalWrite(13, digitalRead(8));
}

The signal pin of the Grove Button attaches to digital pin 8 on the Arduino, and the LED is connected to digital pin 13 on the Arduino. When the button is pressed, it will send a HIGH signal to digital pin 8, which will turn the LED on. When the button is released, the signal will change to LOW and the LED will turn off.