Learning Python With Tron Radio

[5 Volt Junkie] has built his share of Arduino projects, but never anything with Python, and certainly never anything with a GUI. After listening to Internet radio one day, a new idea for a project was born: a Raspberry Pi with a small touchscreen display for a UI and displaying soma.fm tracks. It’s finally finished, and it’s a great introduction to Python, Pygame, and driving tiny little displays with the Pi.

Playing soma.fm streams was handled by mpd and mpc, while the task of driving a 2.8″ TFT LCD was handled by the fbtft Linux framebuffer driver. This left [5 Volt Junkie] with the task of creating a GUI, some buttons, and working out how to play a few streams. This meant drawing some buttons in Inkscape, but these were admittedly terrible, so [5 Volt Junkie] gave up and turned on the TV. Tron Legacy was playing, giving him the inspiration to complete his Tron-themed music player.

The result of [5 Volt Junkie]’s work is a few hundred lines of Python with Pygame and a few multicolor skins all wrapped up in a Tron theme. It looks great, it works great, and it’s a great introduction to Python and Pygame.

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The Teensy Becomes an MPC

A staple of every recording studio today, the Akai MPC began as a simple sampling groove box in the early 90s. The form factor of a few force sensitive pads assignable to different samples should be familiar to anyone with a little bit of MIDI gear, but these are rarely custom-made devices. Now, it runs on a Teensy. [Michele] created his own MPC-style MIDI pad controller with the Teensy 3.0, the Teensy audio adapter board, and an ingenious PCB design that uses replacement MPC pads.

[Michele]’s MPC was first featured in the MIDI hacklet, but back then the only working component was the pads themselves. The velocity sensitive pads are made of two copper traces laid on a single acetate sheet. A bit of Velostat is glued to the back of the pad so when the pad is pressed, it contacts both of the traces. The harder the pad is pressed, the lower the impedance, and with everything sent to an analog pin, each pad becomes a force sensitive resistor.

With the key feature of an MPC taken care of, [Michele] turned his attention to the sampling and software of his device. The new Teensy 3.0 audio adapter board – and a great new library – takes care of everything. [Michele] doesn’t have a proper video of his MPC up yet, but he was able to film a random guy playing his machine at Rome Maker Faire yesterday. You can check that out below.

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Classic 80’s Stereo Receiver Enjoys a Second Life as RadioduinoWRT

radio2[Raffael] had an old Broken Yamaha natural sound receiver lying around. Rather than throw it out, he built himself a slick web radio. He calls it RadioduinoWRT. [Raffael] started by removing all the internals – though he kept the front panel controls.  He then added an Arduino Mega to handle the front panel controls, including a 16×2 character LCD module. The Arduino also takes commands via IR remote. An enc28j60 Ethernet module allows the Arduino to communicate with a the brains of the operation, a TL-WR703N mini router.

A micro USB hub expands the single USB port on the WR703, allowing both a USB sound card and a 4 gig USB stick to be mounted. We’d like to add that the TL-WR703 is a must in this application – the amazon link [Rafael] provides brings up the TL-WR702 as a top link. Only the TL-WR703 has a USB host connection.

The real magic is in [Raffael’s] software setup. The WR703 is running OpenWRT.  He added modules for the USB sound card, as well as expanding the file system onto the USB stick. Once that was complete [Raffael] added Music Player Daemon (MPD) and MPC, a console app to drive MPD. Lighttpd, a light web server provides an interface for the Arduino as well as a web front end to the entire radio.All this allows [Raffael] to control his radio in several ways. He can log in via any web browser on his network. He can use the front panel controls. He can use an IR remote. Since he is running MPD, any client (there are literally hundreds out there) will also drive the radio.

While a low-end USB sound card in a home stereo application does make our inner audiophile cringe a bit, the quality does seem to be pretty good. [Rafael’s] design would make it simple to swap out a higher quality USB sound card if the need arises.

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Laptop Trackpads and MIDI Controllers


A bunch of pads connected to a MIDI out port is as old an idea as the Akai MPC. creating a homebrew version is great, but [Scott] took his version one step further. He used old laptop trackpads to control note on and note off commands when the each pad is tapped, and also added MIDI CC values for the touch pressure and the x and y-axis position.

The trackpads were identical models, each having their own PS/2 output. A few ribbon cable to 8-pin header adapters were manufactured, and the entire ensemble encased in a wonderful maple and aluminum enclosure.

The electronics are based on an Arduino Mega with 16 clock and data points for each touchpad eating up 32 of the 54 available pins on the ‘duino. The PS/2 protocol is well documented, but running 16 separate PS/2 id most certainly not. [Scott] ended up writing his own asynchronous PS/2 communications library to get the latency of his midi device down to about 50ms.

It’s an amazing bit of kit and comparatively inexpensive, given that [Scott] now has a 16-channel Kaoss pad. Video of the device hooked up to a MicroKorg below.

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Hackaday Links: November 24, 2011

Finally an Arduino shield that does nothing

The folks at Evil Mad Scientist labs have finally created the Googly Eye Shield for Arduinos. With it’s pass-through .100 headers, it adds googly eyes to your Arduino projects. Of course, instead of in addition to the googly eyes you could add a breadboard, making it somewhat useful. A million fake internet points goes to the first person to implement Xeyes on this thing.

Phat beats from kids toys

[Ville] couldn’t afford an Akai MPC for laying down some beats. Wanting a real tactile interface, he hacked this kid’s toy. It’s just an RCA cable attached to the tiny chip inside the toy. The new line out goes to his mixers where he does some pretty impressive stuff.

Mona Lisa is Vigo the Carpathian

What did we just say about real-life Xeyes? [Geert] just made a print of the Mona Lisa follow you around the room with her eyes (Dutch, translation). The build is a pair of servos and a DIY motion capture app running on a laptop. Now we need to find a print of Vigo…

Quantifying heat sink efficiencies

[Mike] is an experimenter at heart. He was wondering about the efficiency of small, clip-on heat sinks versus the ones we use to defrost frozen food. The results are exactly as you would expect, but he did find something interesting – his experimental technique didn’t find much of a difference between thermal paste/grease/pads and no thermally conductive material.

Mini-fig sized R/C LEGO car

The guys at Brickmodder.net took a car from a LEGO set and made it remote control. The drive train and steering both use servos controlled by the smallest 3-channel receiver they could find.