The Perils Of Cheap MIDI Adapters

July 11, 2013 by Brian Benchoff 28 Comments

MIDI

[Arvydas] recently bought a Rock Band 3 Wii keyboard thinking it would be an excellent and very inexpensive (£9.99) MIDI controller. The keyboard has a proper DIN-5 MIDI out port, so theoretically the only thing needed to plug this into a computer is a USB to MIDI adapter. Unlike the keyboard, the MIDI adapter was a cheap piece of Chinese cruft, but given some ingenuity and a handful of components, he was able to get everything working.

The 30-year-old MIDI specification includes a few schematics on how to properly connect MIDI devices together. The most important part of these schematics is an optoisolater on the MIDI in, a valuable addition considering early MIDI keyboards cost thousands of dollars. It seems [Arvydas]’ MIDI to USB adapter didn’t include this vital component, instead replacing it with a simple resistor. Anything to keep costs down, right?

To get the MIDI adapter working, [Arvydas] headed over to Maplin and bought an optioisolator, With everything wired up on a breadboard, he got it to work and eventually transplanted the circuit to the adapter’s PCB.

It’s a great piece of work to get this MIDI adapter functioning, especially since it’s doubtful the cheap adapter would have worked with any MIDI device.

Veronica 6502 Gets Keyboard Input Via USB

July 6, 2013 by Brian Benchoff 8 Comments

PS2

When building a homebrew computer, there are a few milestones that make all the work seem worth it. Of course, seeing the CPU step through address lines on the blinkenlights is near the top, but even more important is being able to type a character on a keyboard and have it show up on a display. [Quinn] didn’t want her Veronica computer to deal with serial terminals or PS/2 keyboards when she typed her first characters in; instead she wanted to read a USB keyboard using 80s-era hardware.

Back in the early days of USB, design specs and keyboard manufacturers included a legacy mode in nearly every USB keyboard ever manufactured. This allows a USB keyboard to work with the ancient PS/2 protocol. [Quinn] tapped into that functionality nearly every PS/2 keyboard has using a 6522 Versatile Interface Adapter. This VIA is in the same family of chips as the venerable 6502 CPU that provides GPIO pins and timers.

[Quinn] connected the keyboard connector tapped for PS/2 input to an ATtiny13. This microcontroller reads the scan codes from the keyboards and sends them to the VIA and the rest of Veronica. It’s quite a bit of work to get to this point, but [Quinn] finally has a computer she can type on, the first step to developing software for her homebrew computer.

A Custom Starcraft Keyboard

July 5, 2013 by Brian Benchoff 6 Comments

keybaord

What do you do if you’re looking for a project, but don’t know what to do? If you’re [gltovar], just look around at your hobbies. He’s been playing Starcraft for a while and finally decided to build a custom Starcraft keyboard.

[gltovar] came across an interesting keyboard layout known as TheCore. Ostensibly, this layout allows the player faster access to the commands most used when playing Starcraft. [gltovar] decided he needed a keyboard specifically designed for TheCore, and set about making one of his own design.

The keyboard matrix is designed around a 1×5 row of keys, each attached to a Teensy microcontroller acting as a USB device. Each of these rows are a separate circuit board, allowing [gltovar] to move the rows up and down ergonomically in a custom enclosure.

It’s everything [gltovar] wanted in a custom keyboard. Whether it improves his Starcraft game is another story entirely, but we’re sure he’s at least having fun.

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An XBMC Controller Built For Grandma

June 28, 2013 by Mike Szczys 6 Comments

10-finished-controller

Is your grandmother cool enough to use XBMC? Maybe it’s a testament to the functionality of the wildly popular home entertainment suite rather than the hipness of your elders. But indeed, [Brian’s] grandmother is an XBMC user who needed a controller with larger buttons to accommodate her. This is what he built. He sent us a set of photos and a description of the build, both of which you can see below. He was inspired to get in touch after reading about the custom controller which [Caleb] has been working on for [Thomas].

[Brian] didn’t get bogged down with electronics. He went with the simple, cheap, and popular solution of gutting a wireless keyboard. After tracing out the keys he needed he got rid of everything except the PCB. A wiring harness was crafted by soldering jumper wires to the PCB traces and terminating them with crimping slide connectors. The arcade buttons he used have terminals for the connectors which will make it simple to mate the electronics with the mechanics.

The enclosure is a little wooden hobby box. It originally had a lid with a mirror. [Brian] broke open the lid’s frame to replace it with a thin piece of plywood which hosts the buttons. Inside you’ll find a battery power source. These keyboards last a long time on one set of batteries so he just needs to remember to preemptively replace them from time to time. The finishing touch was to add decals so that granny can figure out what each button does.

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Build A Waterproof Music Controller On The Cheap

June 24, 2013 by Mike Szczys 8 Comments

shower-controller-for-music-playback

[Aaron] wrote in to show off the waterproof music controller (translated) he just finished building. He uses it in the shower — which makes us wonder how long he’s spending in there. We could also see it being useful by the pool, on the beach, or anywhere else that you need a cheap and easy control system.

His computer plays tunes while he’s getting ready for the day. This means he was able to use an inexpensive wireless keyboard for control. The donor keyboard has dedicated music control keys which he carefully traced to the PCB before removing the flexible sheets that detect key presses. Next he found a water tight food container and sized his protoboard to fit. You can see his button layout above. Holes were cut in the lid of the container, with a plastic membrane glued on the underside. This will keep the water out while still allowing him to actuate the momentary push switches.

Most mobile devices will work with wireless keyboards. If your car is nearby just hook your phone to the stereo and control it with this rather than building a dedicated beach stereo system.

Quick And Dirty Touch-sensitive Keyboard Project

June 3, 2013 by Mike Szczys 8 Comments

quick-dirty-touch-sensitive-keyboard

You don’t have to have high-quality parts to play around with electronics and here’s a great example. [Vishal] used junk to play around with CapSense, the touch sensitive Arduino library. What he ended up with is this touch-based piano keyboard.

We’ve featured the CapSense library in the past, but even that example uses a very meticulously crafted test rig of foil tape, protoboard, and some resistors. If you still haven’t given it a try follow this example of using aluminum foil, electrical tape, and a cardboard box.

[Vishal] just sandwiched the end of jumper wire between two pieces of foil to make each ‘key’. We believe the other end of the wire is soldered to the bias resistors where they connect to a couple of pin headers. The headers were hot-glued in place through holes in the bottom of the box, making the entire rig simple to plug into the Arduino board driving it. After adding in a small speaker and flashing the code he’s finished. It certainly makes for a short afternoon project which you won’t feel bad about taking apart later since you didn’t sink a ton of time or resources into the build.