Wiimote Controlled RPi Robot

March 7, 2013 by Eric Evenchick 24 Comments

[Brian] has brought together a powerful collection of hardware to build a robot. The end goal is to have a robot that’s controlled by a Wiimote.

The Wiimote communicates over Bluetooth with a Raspberry Pi, which is running a Python script. This script uses the CWiid Python module to communicate with the controller, and [Brian] has detailed instructions on getting the Wiimote working with a RPi. The RPi controls an ATmega based development board over SPI, which drives an h-bridge to control the two DC motors that move the robot.

[Brian]’s code for this could be helpful for anyone looking to control their RPi with a Wiimote. Since Wiimotes and Bluetooth dongles are fairly cheap nowadays, this is a great way to drop in wireless control to any RPi project, or even to control your media center from the couch.

After the break, check out a video of the build in action

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This Maglite Is A BB Gun

March 6, 2013 by Eric Evenchick 49 Comments

This innocent looking Maglite houses a piston and barrel, making it into a functional pneumatic BB gun. A Maglite was chosen due to its high durability, and easy access to the internals. A schrader valve sticks out of the battery cap, which allows the gun to be charged using a standard fitting. A brass tube is used as the barrel, and a piston controls firing.

Firing the gun is simple. First, the whole thing is charged up to the desired pressure. Then the ammunition is inserted into the barrel. At this point, the rubber piston is held against the end of the barrel by the pressure in the gun. By pushing the pin of the valve in, the piston is able to move back slightly. This acts as the trigger, and causes air to rush into the barrel, firing the BB.

The results are fairly impressive. Using a chronograph, the speed of the BB was measured at 850 feet per second. Using the Gas Gun Design Tool simulator, it was estimated that the gun could fire at over 1000 feet per second, and maybe even break the sound barrier.

Street Art Bot

March 3, 2013 by Eric Evenchick 12 Comments

For the Deconstruction decentralized hackathon, “The FABricators” from Fab Lab Tulsa built a Street Art Bot. The robot drives around and dispenses liquid chalk in a pattern to make sidewalk art.

The FABricators’ robot is based on an electric wheelchair platform. Attached to the base is the hardware for dispensing chalk, which is controlled over wifi. The operator drives the robot around the area to chalk, and chalk is deposited in the right pattern.

In order to ensure the art is chalked correctly, the robot’s software needs to know where the robot is at all times. This is done using a camera mounted above the area and a fiduciary marker that localizes the robot. The tracking is done using the reacTIVision library.

The robot was built to be expandable, and in the future they want to add multiple colors, or even multiple robots printing simultaneously. After the break, check out a video overview of the project.

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RPi Printer Server For Your 3D Printer

March 3, 2013 by Eric Evenchick 20 Comments

Want to run your 3D printer without your laptop attached? Looking to make your hackerspace printer network accessable? OctoPrint aims to make a 3D print server for the Raspberry Pi.

The open source Python project allows you to upload and manage GCODE files on the RPi. You can then select files that you want to print, and get basic statistics before running the printer. Information including temperature can be reported back via the UI, and arbitrary GCODE commands can be run for setup and testing.

Some other nifty features include streaming video to the UI so the print job can be watched remotely. Support for creating time-lapse videos is also available. Adding a wifi dongle and webcam to an RPi turns it into a fully featured print server.

The project uses the Flask web framework to serve the UI, and Tornadio with Socket.io to communicate with the UI asynchronously. You can pull the code from the project’s Github and try it out.

Thanks to [Camerin] for sending this in.

Laser Etching An IPhone 5

March 2, 2013 by Eric Evenchick 33 Comments

CrashBangLabs in Regina recently got their hands on a laser cutter. The Full Spectrum cutter was donated by a local company, who were upgrading to a larger machine.

With no laser cutting experience, [Brett] decided that his first project would be laser engraving his iPhone 5. This is a bit of an ambitious first project, since the power and speed would have to be set correctly to get a good contrast level, and you only have one try to get it right. Also, using too much power might have turn the phone into a laser etched brick.

[Brett] used an older aluminium iPod for testing. Once the laser speed and power was dialed in, he loaded up the artwork for the real thing. The cutter did a pretty good job at etching the art, but as the etching started it became clear that an alignment error had occurred. Fortunately [Brett] decided to not interrupt the cutter, and ended up with a good looking phone, with a slight alignment issue.

After the break, check out a time lapse of the laser cutter doing its thing.

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Hacking A Ham Radio

February 28, 2013 by Eric Evenchick 47 Comments

For Christmas, [Lior] received a Baofeng UV5R radio. He didn’t have an amateur radio license, so he decided to use it as a police scanner. Since the schematics were available, he cracked it open and hacked it.

This $40 radio communicates on the 136-174 MHz and 400-480 MHz bands. It uses a one-time programmable microcontroller and the RDA1846 transceiver. With the power traces to the MCU cut, [Lior] was able to send his own signals to the chip over I2C using an Arduino. He also recorded the signals sent by the stock microcontroller during startup, so that he could emulate it with the Arduino.

Once communication was working on an Arduino, [Lior] decided to get rid of the stock microcontroller. He desoldered the chip, leaving exposed pads to solder wires to. Hooking these up to the Arduino gave him a programmable way to control the device. He got his radio license and implemented transmission of Morse Code, and an Arduino sketch is available in the write up.

[Lior] points out that his next step is to make a PCB to connect a different microcontroller to the device. This will give him a $40 radio that is fully programmable. After the break, check out a video of the hacked radio in action.

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Uzebox Coding Challenge

February 28, 2013 by Eric Evenchick 9 Comments

The 2013 Uzebox Coding Challenge is currently underway. This competition runs until June 1st, with registration open until April 1st. The Uzebox is an open source, 8 bit game console that uses only two chips: an ATmega644 microcontroller and a AD725 RGB to NTSC converter. We’ve featured it a few times in the past.

The competition rules are pretty loose: build a game or a useful piece of software that runs on the Uzebox, and fits in 61 kB. Entries will be judged on game play, originality, graphics, sound, completeness, and technical prowess. There’s prizes for the top six entries, including a few Uzeboxes and cash.

If you don’t have an Uzebox, check out the Uzem emulator. This lets you emulate the Uzebox hardware on Windows, Mac, or Linux. The emulator also has an internal GDB debug server to help with development. The low cost console can be built for about $30, and a number of kits are available.

Thanks to [Ben] for sending this in.