Arduino Hacks

3046 Articles

Android+Arduino – Face Following RC Car

January 15, 2014 by 25 Comments

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To some of us, hacking an RC Car to simply follow a black line or avoid obstacles is too easy, and we’re sure [Shazin] would agree with that, since he created an RC Car that follows your face!

The first step to this project was to take control of the RC Car, but instead of hijacking the transmitter, [Shazin] decided to control the car directly. This isn’t any high-end RC Car though, so forget about PWM control. Instead, a single IC (RX-2) was found to handle both the RF Receiver and H-Bridges. After a bit of probing, the 4 control lines (forward/back and left/right) were identified and connected to an Arduino.

[Shazin] paired the Arduino with a USB Host Shield and connected it up with his Android phone through the ADB (Android Debug Bridge). He then made some modifications to the OpenCV Android Face Detection app to send commands to the Arduino based on ‘where’ the Face is detected; if the face is in the right half of the screen, turn right, if not, turn left and go forward.

This is a really interesting project with a lot of potential; we’re just hoping [Shazin] doesn’t have any evil plans for this device like strapping it to a Tank Drone that locks on to targets!

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An Arduino Library For The PS4

January 13, 2014 by 6 Comments

PS4 Controller

Looking to interface your Arduino with the PS4 controller? [Kristian] has updated his USB host library with support for the controller. The library makes it easy to read most of the inputs from the controller. Currently the buttons and joysticks work, and support for the light sensor, rumble, and touchpad is on the way.

To get this working, you will need the USB Host Shield for the Arduino and a Bluetooth dongle. Once you have the hardware setup, you can use the library to pair with the controller. When connected, simple function calls will let you read the state of the device.

While this does require some additional hardware to connect, all of the code is open source. If you’re looking to experiment with the PS4 controller yourself, [Kristian]’s work could be a helpful starting point. Of course, all of the source is available on Github, and the example sketch shows how easy it is to roll the PS4 controller into your own Arduino project.

Software Half Duplex UART For AVRs

January 13, 2014 by 57 Comments

If you have worked with very low cost microcontroller in the past, such as the ATtiny series from AVR, you’ve probably been stuck without a UART peripheral. The usual answer to this problem is to implement the UART in software. It’s not fast, but it works.

Lets say you’re even more limited on resources, and only have a single pin for UART. [Ralph] created a software library and a small circuit that enables half duplex UART using only one pin. With the above circuit, and a 62 byte Arduino compatible library, you can add UART to the tiniest of ATtinys.

In this circuit, the Tx/Rx pin is on the AVR, and the Tx and Rx pins are another device. The circuit relies on the idle state of UART being a logic high signal. When the Tx pin is idle, the transistor stays on. This allows the Tx/Rx pin to pull Rx low when the AVR sends a 0. When the Tx pin sends a 0, the Tx/Rx pin gets pulled low through the diode.

It’s a clever hack, and could definitely help add communication to your next tiny project.

The Face-Tracking Confectionery Cannon!

January 13, 2014 by 39 Comments

A team of mechanical and electrical engineering students at Olin College came up with a very fun semester project — a pneumatic powered marshmallow cannon that can track faces, and aim for the mouth!

The device — dubbed the Confectionery Canon — is an impressive mechanical build which required many of Olin College’s manufacturing resources such as the laser cutter, the mill, and the lathe. The majority of the device was made out of acrylic, which was chosen for easy laser cutting, and affordability. Specific aluminum pieces provide strength and were made using mostly scrap found in the shop.

Four servos, a webcam, a solenoid and an Arduino Uno make up the electrical system, which uses Python and OpenCV to track faces (GitHub). A PVC tank is used as the pneumatic reservoir, charged with a safety release valve at 30PSI. To fire the cannon, a sprinkler valve is controlled by a beefy solenoid. It currently only has a magazine capacity of 4 large marshmallows, but the team is planning on upgrading soon.

They have put together a great website with tons of information on the project, and following the break is a fun promo video they made for the project — they even got the VP of  the college to try it!

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SquareWear 2.0 A Wearable Opensource Arduino

January 12, 2014 by 37 Comments

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Are you guys tired of redesigned Arduinos yet? Usually we are, but [Ray] just released the SquareWear 2.0, and we have to admit, it’s a pretty slick design.

It’s an update to SquareWear 1.1 which we covered a year ago. That version made use of a 18F14K50 microcontroller, measured a tiny 1.6″ x 1.6″ and could easily be sewn into wearable circuits. But after receiving lots of requests to design a new Arduino based board, [Ray] obliged and made v2.0.

The new SquareWear is slightly bigger, measuring in at 1.7″ x 1.7″, but it packs a much bigger and more functional punch — just check out the image schematic above! The only catch is it doesn’t actually have a USB-to-serial chip on-board, which is why [Ray] was able to get the board so small and inexpensive. Instead it simulates USB in the software using the V-USB library. That method is much slower but still functional. To perform serial communication through the USB port it uses the onboard USBasp bootloader.

The board also features large through-holes to accommodate sew-able pin pads, making it super easy to integrate this into fabric!

For a complete explanation of the SquareWear 2.0, check out the video after the break.

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I Am The Midnight Message Board What Messages At Midnight

January 11, 2014 by 15 Comments

Photoluminescent stars on your bedroom wall or ceiling are pretty cool, though the stationary shapes can become boring. [Adi] felt this way, too. While doodling with a bright white light on some glow in the dark vinyl, it occurred to him that this could make for an interesting display. He set about making GLO, the midnight message board and RSS display.

[Adi]’s light writer uses 12 UV LEDs on a linear axis powered by a stepper motor to write RSS headlines, Twitter trends, or custom text on his wall. He finds the slow fade of the text very soothing to fall asleep by, and it’s easy to see why. The LED array imprints a section of a character consisting of a 6×5 bit pattern. The 12 LEDs are split into two groups, so it can write two lines at 45-50 characters each. [Adi] designed his own pixel font for this project, and advises that only upper case letter forms be used.

[Adi]’s write-up is quite admirable and comprehensive. In the circuit build section, he advises that the LEDs must be very close to the vinyl for optimum results, but that they should protrude farther than the shift registers so the chips don’t rub the vinyl. Of course you could opt for more intense light sources, like laser. See it in action after the break.

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Printer Up-cycled CNC Machine Uses More Than Just The Stepper Motors

January 11, 2014 by 15 Comments

Sometimes you just know from the photo that this is going to be a really cool project. When most people salvage parts from an old printer, they usually chuck the rest. In this case [Shane] made use of the entire printer to build his CNC machine.

He started with an old HP 2500C A3 printer, which he had planned to salvage for parts only. While he was taking it apart he realized the chassis would make a great frame for his actual CNC machine! With that in mind he quickly changed his game plan to making each axis inside of the printer.

He’s using regular ball bearing drawer runners for both the X and Z axes, covered with a clever design of aluminum angle to keep any possible chips from jamming them. The Y axis on the other hand makes use of the original shaft runners from the print head carriage. Each axis is driven by threaded rod using recycled stepper motors from the printer.

An Arduino UNO sits at the heart of the project with a Protoneer CNC shield to control the stepper drivers. He’s also included an emergency stop, hold, resume, and cancel buttons for manual control.

It’s a great project, and an amazing example of using what is on hand for a project. Stick around after the break to see a demonstration of it printing!

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