Posts with «uno» label

An inexpensive device for analyzing roasted coffee beans

While you may not consider in detail how your coffee is roasted, those that produce it must pay special attention to make sure that the end product is consistent. Equipment to help analyze roasted coffee is normally quite expensive, but using a near-infrared sensor, Arduino Uno and Bluetooth module, Spencer Corry was able to make his own analysis setup.

As shown in the video below, after calibration, beans are inserted into the analysis chamber using a tryer scoop. Light is shined onto the roasted beans, and the intensity of the reflected near-infrared radiation is analyzed in six different wavelengths. Intensity data is then transmitted via Bluetooth to a smart device, which can be used to make sure things are roasted perfectly.

There has recently been a growth of small roasting companies offering custom in-house roasts. These companies are looking for less expensive alternatives to hiring and training a roast master or using the expensive Agtron Process Analyzer. The Degree of Roast Infrared Analyzer for Coffee Roasters, as described in this document, is meant to be an inexpensive means of measuring the degree of roast of coffee beans. The Degree of Roast Infrared Analyzer uses a tryer, a tool found on coffee roasters used to sample the coffee during roasting, to hold a sample of coffee. The tryer is inserted into the analyzer where the AS7263 NIR Spectral sensor is used to measure 6 different infrared bands (610, 680, 730, 760, 810, and 860nm). The reflectance measurements are transmitted via Bluetooth and can then be correlated to the degree of roast. The analyzer must first be calibrated by pressing a button on the inside of the box in which the PVC is used as a white balance as it has a relatively flat reflectance in the spectral range detected by the sensor.

An Arduino-based rocket motor thrust test stand

If you enjoy model rocketry, you may wonder just what the thrust curve of the motors you’re using looks like. In order to answer that question, YouTuber ElementalMaker decided to construct his own test stand using an Arduino Uno coupled to a 10Kg load cell with an HX711 amplifier board. The test procedure is started with a little red button, and after warning LED blinks away for 10 seconds, it activates a relay and fires the motor under into the stand.

The experimental setup seen in the video yields successful thrust curves for both a ½ inch and ¾ inch motor. As you might expect, the ¾ produces more thrust than its smaller cousin, though at 2,683 grams versus the ½ inch motor’s 658, it’s an impressive difference indeed. 

The heart of the stand is a common load cell (the sort of thing you’d find in a digital scale) coupled with a HX711 amplifier board mounted between two plates, with a small section of vertical PVC pipe attached to the topmost plate to serve as a motor mount. This configuration is capable of measuring up to 10 kilograms with an 80Hz sample rate, which is critically important at this type of rocket motors only burn for a few seconds to begin with. The sensor produces hundreds of data points during the short duration of the build, which is perfect for graphing the motor’s thrust curve over time.

Given such a small window in which to make measurements, [ElementalMaker] didn’t want to leave anything to chance. So rather than manually igniting the motor and triggering the data collection, the stand’s onboard Arduino does both automatically. Pressing the red button on the stand starts a countdown procedure complete with flashing LED, after which a relay is used to energize a nichrome wire “electronic match” stuck inside the motor.

The project is based on a paper archived here if you’d like to examine the design.

Build a single-pixel scanning camera with an RGB sensor

Sensors like the TCS34725 from Adafruit can detect a single color. It stands to reason then, that if you were to aim this sensor at a multitude of points and record the resulting data, you could have a one-pixel camera. As seen here, Tucker Shannon decided to take this concept and run with it, constructing his own with an Arduino Uno and a pair of stepper motors.

The device looks like something akin to some sort of auto-turret, and directs the sensor in a square spiral for image acquisition. The resulting pictures are certainly low-res, but good enough to pick out recognizable forms with a little imagination. 

The color sensor tells the Arduino what color it “sees” at any given time. By pointing it at every single point within a field of view, I can record these colors and use them later to reconstruct an image.

Using two stepper motors, the camera points the sensor at every “pixel” within the photo and records what it sees. It uses these values to “paint” a picture of whats in front of it!

Components include: 1x Arduino Uno, 1x Adafruit RGB Color Sensor TCS34725, x2 BYJ-48 Stepper motor with drivers, x1 3mm OD aluminum tube, x20 M3x6mm fasteners. Alternatively a photoresistor can be used in place of the RGB sensor for black and white photos!

Code for the project can be found on GitHub, and print files are on Thingiverse if you’d like to build your own!

Keep track your weekly tasks with Arduino and arcade buttons

All of us have daily tasks we need to perform, but what if you often forget whether you’ve done something, or simply need to give your child a little extra motivation? One great way would be Simon Prickett’s Arduino Task Tracker, inspired by Simone Giertz’s Every Day Calendar. 

Prickett’s clean-looking device is built into an electrical junction box, which holds the guts, including an Arduino Uno inside. It also exposes eight arcade-style LED buttons on top.

After you, or in this case Prickett’s son, complete a chore, press one of the seven green buttons. Once they are all lit, the Arduino Task Tracker produces a “victory roll” sequence. The eighth red button is then used to start the week over again. 

Sound like something you’d like to recreate? Code and more info for the project can be found GitHub.

Mood-controlled RGB light wall

In the build shown below, Evan McMahon dares to ask the question, “Have you ever been disappointed by a mood ring?” While that might seem a bit random, the answer is a likely “yes” if you’ve ever worn one with the expectation of any sort of accuracy. Fortunately, he didn’t just pose the question, but also came up with a clever solution, using an array of lights under Arduino control.

For the setup, McMahon uses the camera on his iPhone to take video of his smiling or frowning mug, then analyzes it with the help of Unity running on a computer to translate this into his apparent state of mind.

This info is then sent to an Arduino Uno, which puts the programmable LED lights into dance mode if he’s happy, and makes them shine blue if he’s a bit blue himself!

Arduino Blog 05 Dec 14:44

Simple PID control intro device

You may have come across the term “PID control,” and while this proportional-integral-derivative control method does a great job of smoothing out oscillations, where does one get started? 

One solution would be Mr Innovative’s demo device, showcased in the video below. In it, a DC gear motor is able to smoothly rotate an arrow overlaid on a protractor by a certain number of degrees.

Input is via a Bluetooth smartphone interface, and an encoder is used for feedback to the commanding Arduino Uno. Everything is fastened together by 3D-printed parts, and if you’d like to try your own PID experiment, code and print files are linked in the video description.

Keyboard dampener prototype aims to reduce typing injuries

While we don’t normally think of typing on a computer as a dangerous job, the U.S. Department of Labor reports that workers spend 25,000 hours away from work due to repetitive strain injuries, such as using a computer. Part of this could be due to the fact that the average computer user applies two to seven times the necessary force needed to activate a keyboard’s keys, slamming them down, then experiencing a sudden stop.

In order to help cushion these small blows, researchers Alec Peery and Dušan Sorma at Ohio University have been exploring a mechanical keyboard concept with a 3D-printed dampener built in. Testing has been undertaken using the popular Cherry MX switches, with typing simulated by dropping a 150 gram cylinder from 125mm, then measured using an Arduino Uno and force sensing resistor.

This paper is a demonstration of how 3D printing can be used to create a composite (plastic and rubber) keyboard switch that is ergonomically superior to a traditional injection moulded plastic switch. The prototype switch developed in this project aims to reduce impact forces from keyboard use exerted on user’s fingers by “cushioning” the act of bottoming out the switch during a key press. This concept is significant to industry because it aims to reduce overuse injuries caused from work on computer, a portion of the $20 Billion a year owed in worker compensation in the United States. A commercial Cherry MX keyboard switch has been modified through CAD modelling and 3D printing to incorporate damping regions in the lower half of the switch housing. The switch housings were simultaneously 3D printed with plastic and rubber and their force damping properties were tested with an Arduino UNO microcontroller and force sensing resistor resting on the key tops.

The full research paper is available here.

Stream weather conditions to the cloud!

Weather reports on the news, your computer, or smartphone are very good—something that people 100 years ago could only dream of—but what if you want to know the exact weather in a fixed location from anywhere in the world? One solution would be Jakub Nagy’s excellent cloud-connected station.

It uses an Arduino Uno to collect data from temperature, humidity, pressure, and UV index sensors, along with a Nano to read a rain gauge. The data, with images from a webcam, are passed along to a service called Weathercloud, where this report out of the Slovak Republic can be viewed remotely. 

If you’d like to assemble a similar device to measure conditions in your area, instructions are available in his write-up, including a parts list that will run around $130.

Upgrade a sewing machine into an automatic embroidery rig

A needle and thread is extremely useful if you need to fasten a few pieces of fabric or sew on a button, and a sewing machine takes things up several notches in speed an accuracy. This venerable machine, however, can now be enhanced with a trio of stepper motors under Arduino Uno GRBL control to take things to an entirely new level.

The “Self-Made Embroidery Machine” employs a setup very similar to a 3D printer or CNC router. Two steppers move the fabric around, while a third actuates the needle. This allows the user to program in decorative shapes and patterns as shown in the video below, and the build process is well documented if you’d like to build your own!

Sewing machine part is any old or new sewing machine. Only change for original is stepper motor with synchronised pulley system (chain/belt drive) and more embroidery friendly presser foot. It is recommended to use older sewing machine, way more convenient to mount stepper motor to cast iron and prices are relatively cheap.

XY movement consists mainly 3D printed parts, 12 pcs and similar parts known from self build 3D printers. Both axes use GT2 belts, NEMA 17 steppers and both directions are fully scalable.

Synchronous movement comes from Arduino powered GRBL G-code interpreter, it is mouthful, but basically machine moves using G-code send to Arduino. It is not that complicated and it is only carrier like any other one when going from system to another one.

Now we have movement and code, but how to make nice shapes and export to G-code. It is nothing to do with medieval sorcery, it is a matter of downloading Inkscape and extension called Inkstitch.

Help and examples how to use Inkstitch extension can be found address above. End result should be really close to hobby level embroidery machines, just slower speed. After all, embroidery machine is nothing more than overgrown sewing machine.

Convert a Dremel tool into an Arduino-controlled CNC machine

3D printers get most of the attention in maker-fabrication news, but other computerized tools, like laser cutters and CNC routers, can also be extremely useful. In fact, Nikodem Bartnik decided to create his own Dremel-based machine constructed out of 3D-printed parts and aluminum profiles. 

Electronics include an Arduino Uno and CNC stepper shield running GRBL for control, along with some NEMA 17 steppers and motor drivers, a relay for the Dremel, and a 12V / 30A power supply.

As with many other projects, his build went through several iterations, but the final results—seen in the video below—are quite good. The machine, which only cost him around $300, is able to mill MDF and acrylic.

If you’d like to make your own, Bartnik outlines his design in the first video below, then shows how to use it in the second.