Posts with «uart» label

You Can Send MIDI Over I2C If You Really Need To

The Musical Instrument Digital Interface has a great acronym that is both nice to say and cleanly descriptive. The standard for talking to musical instruments relies on a serial signal at 31250 bps, which makes it easy to transmit using any old microcontroller UART with a settable baud rate. However, [Kevin] has dived into explore the utility of sending MIDI signals over I2C instead.

With a bit of hacking at the Arduino MIDI library, [Kevin] was able to get the microcontroller outputting MIDI data over the I2C interface, and developed a useful generic I2C MIDI transport for the platform. His first tests involved using this technique in concert with Gravity dual UART modules. After he successfully got one running, [Kevin] realised that four could be hooked up to a single Arduino, giving it 8 serial UARTS, or, in another way of thinking, 8 MIDI outputs.

At its greatest level of development, [Kevin] shows off his I2C MIDI chops by getting a single Raspberry Pi Pico delivering MIDI signals to 8 Arduinos, all over I2C. All the Arduinos are daisy-chained with their 5V and I2C lines wired together, and the system basically swaps out traditional MIDI channels for I2C addresses instead.

There’s not a whole lot of obvious killer applications for this, but if you want to send MIDI data to a bunch of microcontrollers, you might find it easier daisy-chaining I2C rather than hopping around with a serial line in the classic MIDI-IN/MIDI-THRU fashion.

We’ve seen [Kevin]’s work before too, like the wonderful Lo-Fi Orchestra. Video after the break.

Hack a Day 16 Feb 06:00

Arduino And IR Remote Turn Off Raspberry Pi

With all of the cool features on the Raspberry Pi, it is somewhat notable that it lacks a power button. In a simple setup, the only way to cut power to the tiny computer is to physically remove the power cord. [Dalton63841] found that this was below his wife’s tolerance level for electronics, and built a simple remote control for his Raspberry Pi.

[Dalton63841] started this project by trying to use the UART TX pin, but this turned out to be a dead-end. He decided instead to use an Arduino to monitor the 3.3V power rail on the Pi. When the Pi is shut down in software, the Arduino can sense that the Pi isn’t on any more and disconnect the power. The remote control is used to turn the Pi on. The Arduino reads the IR code from a remote and simply powers up the Pi. This is a very simple and elegant solution that requires absolutely no software to be installed on the Raspberry Pi.

We know that this isn’t the most technically complex project we’ve ever featured, but it is a good beginner project for anyone just getting started with a Pi, Arduino, or using IR. Plus, this could be the perfect thing to pair up with a battery-backup Raspberry Pi shutdown device that allows it to power itself down in a controlled way when a power outage is sensed.


Filed under: Arduino Hacks

Hackaday Links: May 11, 2014

North Korean drones! Yes, your local hobby shop has the same aerial reconnaissance abilities as North Korea. Props to Pyongyang for getting v-tail mixing down.

There’s nothing quite as satisfying as the look of a well laid out resistor array, and the folks at Boldport have taken this to a new level. It’s an art piece, yes, but these would make fabulous drink coasters.

Here’s something even more artistic. [cpurola] found a bunch of cerdip EPROMs and bent the pins in a weird chainmaille-esque way. The end result is an EPROM bracelet, just in time for mother’s day. It’s a better use for these chips than tearing them apart and plundering them for the few cents worth of gold in each.

[John] still uses his original Xbox for xmbc, but he’d like to use the controllers with his computer. He never uses the third and fourth controller ports, so he stuck those in his computer. It’s as simple as soldering the controller port module to a connector and plugging it into an internal USB port. Ubuntu worked great, but Windows required XBCD.

[Kerry] has modified an FT232 USB/UART thingy as an Arduino programmer before. The CP2102 USB/UART is almost as popular on eBay, a little less expensive, and equally suited for ‘duino programming. It requires desoldering a resistor and soldering a jumper on a leadless package, but with a fine solder tip, it’s not too bad.

 

 

 

 


Filed under: Hackaday links
Hack a Day 12 May 00:00