BeagleBones And Teensies Become KVMs

[pmf], like most of us, I’m sure, spends most of his days on a computer. He also has a smartphone he keeps at his side, but over the years he’s grown accustomed to typing on a real keyboard. He came up with the idea of making a USB switch that would allow his keyboard to control either his computer or his phone, and hit upon a really neat way of doing it. He’s using a BeagleBone Black and a Teensy to switch his keyboard between his computer and his phone with just a press of a button.

This homebrew smart KVM uses a BeagleBone Black for most of the heavy lifting. A keyboard and mouse is connected to the USB host port of the BeagleBone, and the main computer is connected to the device port. The BeagleBone is set up to pass through the USB keyboard and mouse to the computer with the help of what Linux calls a ‘gadget’ driver. This required an update to the Linux 4.0 kernel.

With the BeagleBone capable of being a USB pass through device, the next challenge was sending keypresses to another USB device. For this, a Teensy 2.0 was connected to the UART of the BeagleBone. According to [pmf], this is one of the few examples of the Teensy serving as a composite USB device – sending both keyboard and mouse info.

There are a few neat features for [pmf]’s build: the keyboard and mouse don’t disconnect when switching, and thanks to a slight modification of the USB OTG adapter, this will also charge a phone as well as allow for the use of a keyboard. Because the BeagleBone Black has more than one UART this build can also switch keyboards and mice between more than two computers. For those of us who invest heavily in keyboards, it’s a godsend.

Hackaday Links: July 20, 2014


Etch-a-Sketch spray-painted silver with electronics bolted onto the side? Sign us up! This art installation adds one thing that we don’t often see in these types of hacks, eerie audio.

If you’re still mining bitcoin you need to do it faster than anyone else… that’s pretty much how the whole thing works. [Lewin] has been using the Antminer USB ASIC and toyed around with overclocking to 2.2 GH/s (gighashes per second) but to make sure his hardware holds up to the overwork he hacked his own water cooling system for the dongle.

Smart phones are the best bang for your buck on portability and power. Better yet you can get slightly broken ones for a song. If you manage to find an Android device with a broken touch screen but functioning LCD try this trick to add a mouse to it. There must be another life for this in a future hack!

We have a love-hate relationship with this particular crowd-funding campaign. First this hate: It’s basically a 100% clip-art video presentation with an $800,000 ask. Yeah… good luck buddy. On the other hand, this is the type of stuff we actually want to see as crowd funding. The idea is to use modern materials and techniques to build [Nikola Tesla’s] Wardenclyffe Tower, which was designed and built to research wireless energy (both as a means of communication and actual energy transfer). It was never fully functional and ended up being demolished. Wouldn’t it be great if teams of highly skilled and motivated people took grand ideas like this, crossing every theoretical “t” and dotting every theoretical “i”, and then proposed a crowd funding campaign to build a test platform? Oh wait, that sounds very much like a government research grant. Anywhoo… check out the Global Energy Transmission’s campaign.

LED-Guided Piano Instruction


[Kay Choe] can’t play the piano. Rather, he couldn’t, until he converted his keyboard to include LED-guided instruction. [Kay] is a microbial engineering graduate student, and the last thing a grad student can afford is private music lessons. With $70 in components and a cell phone, however, he may have found a temporary alternative.

The build works like a slimmed-down, real-world Guitar Hero, lighting up each note in turn. We’ve seen a project like this before, with the LEDs mounted above the keys. [Kay]’s design, however, is much easier to interpret. He embedded the LEDs directly into the keys, including ones above each black key to indicate the sharps/flats. An Android app takes a MIDI file of your choice and parses the data, sending the resulting bits into an IOIO board via USB OTG. A collection of shift registers then drives the LEDs.

For a complete novice, [Kay] seems to benefit from these lights. We are unsure whether the LEDs give any indication of which note to anticipate, however, as it seems he is pressing the keys after each one lights up. Take a look at his video demonstration below and help us speculate as to what the red lights signify. If you’re an electronics savant who wants to make music without practicing a day in your life, we recommend that you check out [Vladimir’s] Robot Guitar.

Continue reading “LED-Guided Piano Instruction”

New IOIO is faster, cheaper


For the last few years, [Ytai] has been working on the IOIO, a device that connects your Android devices to the other homebrew peripherals. There’s a new version of this really cool board out now that includes a few much-needed features like USB-OTG and a lower component cost that is passed on in savings to you.

A few months ago, our own [Mike Szczys] caught a glimpse of this new IOIO board. It’s the same size as the previous revision, but with USB-OTG, the new IOIO can be a master when connected to a phone, or a slave when connected to a PC.

In addition to USB-OTG, [Ytai] improved the power regulation circuit, and even went so far as to refuse royalties to the board to get the costs down. It’s currently available at Sparkfun for $40.

[Ytai] says he’s working on a few software upgrades to the IOIO, including making capacitive sensing a possibility and including support for stepper motors and controllers. There’s also support for the Raspberry Pi coming up, but we’re just glad [Ytai] managed to put a yo-yo graphic on the bottom silkscreen. Finally, and hopefully, everyone will know how to pronounce IOIO.

Custom flat cables to suit your needs

[Cosimo Orlando] has a Motorola Xoom tablet. It’s an Android device that works great as a tablet, but can double as a Laptop when you need it to by adding a keyboard. The problem he was having is that the USB On-The-Go cables that he tried were never the right size or orientation. So he scavenged them for parts and built his own flat cable for a custom fit.

The final product pictured here actually uses protoboard to give the body some strength. [Cosimo] first laid out the dimensions on the substrate using a felt-tipped pen. He then took connectors from his mis-sized commercial cables and affixed them to the board with a combination of hot glue and solder. From there, just connect the five data lines and ground with some jumper wire and test for continuity. He finished this off with what he calls ‘adhesive plastic glossy black’ shaped to make a decent looking case. If you have any idea what product was used here, let us know by leaving a comment.

Forknife, Android G1 controlled robot


When we first saw [Jeffrey Nelson]’s G1 based robot we immediately wondered what the transport for the controls was. The G1‘s hardware supports USB On-The-Go, but it’s not implemented in Android yet. It turns out he’s actually sending commands by using DTMF tones through the headphone adapter. The audio jack is connected to a DTMF decoder that sends signals to the bot’s Arduino. He wrote client/server code in Java to issue commands to the robot. You can find that code plus a simple schematic on his site. A video of the bot is embedded below.

Continue reading “Forknife, Android G1 controlled robot”