Arduino Hacks

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Trackpad with Arduino PS/2-to-USB converter

Raspberry Pi Trackpad From Salvaged Trackpad Plus Arduino

July 19, 2017 by 39 Comments

Old laptops are easy to find and many have a trackpad with a PS/2 interface hardwired into the guts of the laptop. [Build It] wanted one of those trackpads for use in the DIY Raspberry Pi laptop he’s working on. But the Raspberry Pi has no PS/2 input, and he read that a PS/2 to USB adapter wouldn’t be reliable enough. His solution? Wire the trackpad to an Arduino and have the Arduino convert the trackpad’s PS/2 to USB.

After removing a few screws, he had the trackpad free of the laptop. Looking up the trackpad’s part number online he found the solder pads for data, clock and five volts. He soldered his own wires to them, as well as to the trackpad’s ground plane, and from there to his Arduino Pro Micro. After installing the Arduino PS/2 mouse and the Mouse and Keyboard libraries he wrote some code (see his Instructables page). The finishing touch was to use generous helpings of hot glue to secure all the wires, as well as the Arduino, to the back to the trackpad. By plugging a USB cable into the Arduino, he now had a trackpad that could plug in anywhere as a USB trackpad. Watch [Build It] put it all together step-by-step in the video below.

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PLC Vs Arduino Show Down

July 17, 2017 by 84 Comments

Hackaday readers don’t need an introduction to the Arduino. But in industrial control applications, programmable logic controllers or PLCs are far more common. These are small rugged devices that can do simple things like monitor switches and control actuators. Being ruggedized, they are typically reasonably expensive, especially compared to an Arduino. [Doug Reneker] decided to evaluate an Arduino versus a PLC in a relatively simple industrial-style application.

The application is a simple closed-loop control of flow generated by a pump. A sensor measures flow for the Arduino, which adjusts a control valve actuator to maintain the specified setpoint. The software uses proportional and integral control (the PI part of a PID loop).

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Make Some Noise With The Typewriter Keyboard

July 16, 2017 by 11 Comments

Are you an angry programmer? Do you get the frequent urge to smash the return key or space bar after finishing every single line of code? Well then [Konstantin Schauwecker]’s typewriter keyboard is just the thing for you. In his project, [Konstantin] hacked a German Olympia Monica typewriter into a USB keyboard.

The project uses no less than 50 photo interrupters mounted on a custom PCB that mounts directly under the typewriter itself. The circuit board is so designed that the hammer arms take a position in obstructing the opto-interrupters. Every time a key is pressed, the corresponding device sends a signal to an Arduino.

In order to enable the wiring of 50 signals to an Arduino Leonardo, multiplexers and decoders are employed. CD4515, 4×16 line decoders work to activate the optical signals and the CD4067, 16×4 multiplexers are used to return the scans. This forms the traditional scanning keyboard matrix and the whole thing is managed in the Arduino code (available as a zip file).

This project can be a great starting point for anyone who wants to hack their grandpa’s old typewriter or make one in order to annoy the guy sitting next to them. Check out the video below for a demo and teardown and if you prefer Raspberry Pis then check out this mechanical typewriter hack.

Reflective Sensor Becomes Kart Racing Lap Counter

July 15, 2017 by 8 Comments

Once you have a track and a kart to race on it, what’s missing? A lap counter that can give your lap times in hardcopy, obviously! That’s what led [the_anykey] to create the Arduino-based Lap Timer to help him and his kids trim those precious seconds off their runs, complete with thermal printer for the results.

The hardware uses an infrared break-beam sensor module (a Velleman PEM10D) to detect when a kart passes by. This module is similar to a scaled-up IR reflective object sensor; it combines an IR emitter and receiver on one end, and is pointed at a reflector placed across the track, up to 10 meters away. When a kart breaks the beam, the module reports the event to the rest of the hardware. Only needing electronics on one side allows the unit to be self-contained.

An obvious shortcoming of this system is the inability to differentiate between multiple karts, but for timing a single driver’s performance it does the trick. What’s great about this project is it showcases how accessible hardware is today; a device like this is possible to put together with what are essentially off-the-shelf components available to any hobbyist, using an Arduino as the glue to hold it together. We’d only comment that a red-tinted piece of plastic as an overlay for the red display (and a grey-tinted one for the green) would make the LED displays much easier to read. Still, this is a very clean and well-documented build. See it in action in the video embedded below.

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JPEG Decoding, Arduino Style

July 12, 2017 by 32 Comments

When you think of image processing, you probably don’t think of the Arduino. [Jan Gromes] did, though. Using a camera and an Arduino Mega, [Jan] was able to decode input from an Arduino-connected camera into raw image data. We aren’t sure about [Jan’s] use case, but we can think of lots of reasons you might want to know what is hiding inside a compressed JPEG from the camera.

The Mega is key, because–as you might expect–you need plenty of memory to deal with photos. There is also an SD card for auxiliary storage. The camera code is straightforward and saves the image to the SD card. The interesting part is the decoding.

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Tinkercad Does Arduino

July 11, 2017 by 12 Comments

If you’ve done 3D printing, you’ve probably at least heard of Tinkercad. This popular CAD package runs in your browser and was rescued from oblivion by Autodesk a few years ago. [Chuck] recently did a video about a new Tinkercad feature: building and simulating virtual Arduino circuits. You can watch it below.

There are a variety of components you can add to your design. You’ll find an integrated code editor and a debugger. You can even get to the serial monitor, all in your browser with no actual Arduino hardware. You can also build simple circuits that don’t use an Arduino, although the component selection is somewhat limited.

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Robot Solves Sudoku On Paper

July 10, 2017 by 13 Comments

Sudoku is a great way to pass some time, especially on a long flight. However, we don’t think the airlines will let [Sanahm] board with his sudoku-solving robot. The basic machine looks like a 2D plotter made with aluminum extrusion, with the addition of a Raspberry Pi and a camera. The machine can read a sudoku puzzle, solve it, and then fill in the puzzle with a pen. Unlike humans, it should never need to erase its work.

The software uses OpenCV to process the camera data, find the grid, and the cells provided by the puzzle. TensorFlow recognizes the numbers. From there, it is all just math to solve the puzzle. Once solved, the plotter part of the robot takes over and fills in the blanks. After all that, this seems like the easy part.

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