Posts with «featured» label

Blow out this Arduino LED candle!

LED candles can provide a nice sense of ambiance, without the inherent associated risk of fire. For better or worse, however, they don’t normally respond to air currents. 

Paul Dietz, however, shows that this kind of response is actually possible, as an LED’s forward voltage drop is affected by how well it dissipates heat due to ambient air conditions.

This means that when you puff on an LED, the resulting voltage changes can be picked up by an Arduino Uno.

LEDs are designed to emit light, but they also make surprisingly capable sensors. Using only an Arduino UNO, an LED and a resistor, we will build a hot LED anemometer that measures wind speed, and turns off the LED for two seconds when it detects you are blowing on it. You can use this to make breath controlled interfaces, or even an electronic candle that you can blow out!

How Does This Work? 

When you run current through an LED, its temperature rises. The amount of rise depends on how effectively you are cooling it. When you blow on a hot LED, the extra cooling lowers the running temperature. We can detect this because the forward voltage drop of an LED increases as it gets cooler.

The circuit is very simple and looks much like driving an LED. The only difference is that we will add an extra wire to measure the voltage drop of the LED while it is on. To work well, you want to use a very small LED (I suggest using an 0402 surface mount LED) connected by the thinnest possible wires. This will allow the LED to heat and cool very quickly, and minimize the heat lost through the wires. The voltage changes we are looking for are just millivolts – at the very edge of what can be reliably detected via the UNOs analog pins. If the LED is resting on something that conducts heat away, it may not be able to get hot enough, so it works best if it is up in the air.

As shown in the video below, he turned this concept into a novel “candle” setup, blowing his tiny 0402 SMD-format LED out over and over—like a trick birthday candle!

Arduino Blog 21 Aug 18:48

DeepWay helps the visually impaired navigate with a tap

In order to help those with visual impairments navigate streets, college student Satinder Singh has come up with an innovative solution that literally pokes the user in the right direction. 

Singh’s system, called DeepWay, uses a chest-mounted camera to take images of the road that a wearer is walking down, then feeds this information to a laptop for processing. 

If the deep learning algorithm determines that the user needs to move left or right to stay on the path, a serial signal is sent to an Arduino Uno, which in turn commands one of two servos mounted to a pair of glasses to tap the person to indicate which way to walk. Additional environmental feedback is provided through a pair of earphones.

This project is an aid to the blind. Till date there has been no technological advancement in the way the blind navigate. So I have used deep learning particularly convolutional neural networks so that they can navigate through the streets.

My project is an implementation of CNNs, and we all know that they require a large amount of training data. So the first obstruction in my way was a correclty labeled dataset of images. So I went around my college and recorded a lot of videos (of all types of roads and also off-roads). Then I wrote a basic Python script to save images from the video (I saved 1 image out of every 5 frames, because the consecutive frame are almost identical). I collected almost 10,000 such images almost 3,300 for each class (i.e. left right and center).

I made a collection of CNN architectures and trained the model. Then I evaluated the performance of all the models and chose the one with the best accuracy. I got a training accuracy of about 97%. I got roughly same accuracy for all the trained model but I realized that the model in which implemented regularization performed better on the test set.

The next problem was how can I tell the blind people in which direction to move. So I connected my Python program to an Arduino. I connected the servo motors to Arduino and fixed the servo motors to the sides of a spectacle. Using serial communication I can tell the Arduino which servo motor to move which would then press to one side of the blind person’s head and would indicate him in which direction to move.

A demo of DeepWay can be seen in the video below, while code for this open source project is available on GitHub.

Build a 4-button arcade game out of LEGO

If your kids (or you) have somehow gotten tired of playing with LEGO bricks, Lenka Design Workshop has a great way for you to breathe new life into this unused pile. 

Their game enclosure consists of a 32×32 LEGO baseplate, along with walls made of blocks to support a clear acrylic cover. This in turn holds four large arcade buttons for gameplay control. Five games are currently implemented to run on the game’s Arduino, with light and sound feedback.

We decided to recycle the unwanted Lego bricks and created an arcade game.

The code has been written in such a way that it doesn’t have dependencies and will compile on any Arduino board. And of course the games have been intensively tested by our kids.

How is this game different from many others that have been published before?

First of all, there are 5 games built into it:

  • Memory Game (“Simon-Says”-like, similar to Touch Me game)
  • Reaction game (similar to Whack-a-Mole game)
  • Contest/Competition game (for 2-4 players)
  • Melody Game (Push and Play free mode for toddlers and smaller ones)
  • War game (for 2-4 adults)

Secondly, it has a great design (from our perspective) and can be easily repeated.

And thirdly, it is earth-friendly because it allows you to recycle the plastic.

You can see a short demo of the system in the video below, or check out the project write-up for more info. 

Arduino Blog 17 Aug 15:58

Make your own soda fountain out of cardboard

If you’re ever wanted to make something awesome, but thought that you just didn’t have the right tools to do so, this soda fountain by “The Wrench” could provide the needed inspiration. 

The project uses an Arduino Nano to control a small air pump via a relay, which turns on when a glass is the correct dispensing position. This pushes air into a sealed soda bottle, and soda is pushed out of another tube to equalize the pressure.

It’s a certainly a neat trick. Given its frame made out of cardboard stuck together with hot glue, the raw materials are very easy to obtain and dispose of when needed. The build process is explained in the video below, while the circuit diagram and Arduino code can be found here.

An Arduino-controlled turntable for 3D scanning

Many DSLR cameras can be operated with a simple infrared signal, making them perfect targets for Arduino control. Travis Antoniello took advantage of this with his brilliantly simple 3D scanning rig.

Electronics are handled by an Arduino Uno, which commands a stepper motor to rotate a scanning platform 10 degrees per photo. After rotation, it stops for a set amount of time to let scanned objects settle, and triggers the camera, a Nikon D3200, via an infrared LED. It then repeats this process over and over until a full set of photos is taken. 

Code for the build can be found on GitHub, and the device’s 3D-printed components are available on Thingiverse. The project video seen here gives a good overview of how it works, and the scanned object on display just after 2:30 looks absolutely brilliant.

Turn the pages on your Kindle remotely with Arduino

As seen here, Alex Mikes enjoys reading his Kindle in bed at night, but prefers to use a stand rather than hold it in his hands. The one disadvantage to this is that one normally has to lift his or her hand up to change pages. Thanks to a clever bit of engineering, Mikes only has to press the button on a small RF remote, signaling an Arduino Nano-based robot to press it for him.

The device uses a micro servo motor to actuate the fake finger, which swings into the correct position to advance pages on command. A 3D-printed frame holds everything in place, and in order to properly control his Kindle’s capacitive touchscreen, a wire is wrapped inside the stylus tip and connected to the circuit ground. 

Not since Rick and Morty’s butter-passing robot has there been a more hyper-specific, purpose-built device than perhaps Alex Mikes’ automatic Kindle page turner. Instead of having to raise his arm to tap the edge of the screen while reading in bed, a simple click of a wireless remote makes the attached contraption do all of that hard work for him.

More photos of the project are up on Imgur.

Monopoly transformed into the world of Skyrim with LEDs and Arduino

While “Boardwalk” and “Park Place” may not mean anything to you outside of the game of Monopoly, there is a plethora of custom versions to suit your particular interest. If you enjoy the world of Skyrim, then you need to check out this board by Charles Ledford. 

The build features an anodized aluminum playfield coated in epoxy, along with a wooden frame that conceals electronics including an Arduino Uno inside. This enables a set of programmable LED strips to light up a dragon and lettering in the middle, as well as properties in the correct Monopoly color. 

Custom coins, playing cards, characters, and even farms and castles (houses and hotels) complete the project, allowing for fully Skyrim-themed gameplay!

You can find more details in Ledford’s write-up, and see a quick demo of it below! 

Thomas the Tank Engine turned into a karaoke robot

When Hunter Irving spotted a knockoff Thomas the Tank Engine toy at a thrift store, he simply had to buy it, telling himself that he’d turn it into an animatronic contraption at some point. While these kind of promises often go unfulfilled, Irving converted it into an egg-shaped, karaoke-singing robot, with a mouth and eyes that move along with music.

The body of this new robotic device is designed in Blender and 3D-printed, while the mechanicals inside are actuated with a servo. Control is handled by an Arduino, which responds to MIDI signals from a speech synthesizer, used to produce its eerie electronic voice. 

Electric-powered fan rocket takes off and lands(?) vertically

Does a rocket need to use a certain type of fuel, or even be capable of spaceflight? While James Bruton’s build might not fit everyone’s definition of this type of craft because of its electric ducted fan (EDF) propulsion, it does face the same major challenge of controlling a tall pipe-like structure from thrust coming from the tail. It’s meant to both take off and land in a vertical orientation as well, something inconceivable in traditional rockets until very recently.

For control, Bruton uses an Arduino Mega inside the main fuselage of the craft, which regulates the speed of the three EDFs. It also turns two of these fans with a servo and linkage system in order to compensate for unwanted roll. A second Arduino and an IMU are embedded in the nose cone, which passes data to the Mega board via a serial connection. 

The build and early tests can be seen in the video below, and a full test is planned for the future alongside Ivan Miranda, who has been working on his own version.

Check the weather on this Arduino-controlled split-flap display

Split-flap displays show information using characters changed by an electric motor. While they’ve largely been replaced by more modern means, hobbyists like “gabbapeople” have been keeping this this technique alive, in this case as a four-character weather display.

The device is built using laser-cut plexiglass, and uses four individual servos to actuate the character flaps. Control is accomplished using an Arduino Mega programmed in the XOD visual programming environment, along with the requisite driver modules. Weather data is pulled from the AccuWeather API. 

You can see it flapping away in the video below, displaying the weather in abbreviations such as “ICLO” for intermittent clouds, as well as the temperature in degrees Celsius.