Mechanical Keyboard Goes BLE

Like many programmers, [Daniel Nugent] loves his old mechanical keyboard (a WASD Code Keyboard). What he didn’t love was the cord. Sure, you can get a modern wireless keyboard, but it won’t be the same as the keyboard you’ve spent so much time with. Armed with a Bluetooth Low Energy (BLE) module, a rechargeable battery and some coding, he kept his keyboard but got rid of the wires.

Although he has some specific handling for the WASD, the code would very likely handle any PS/2 keyboard. The PS/2 interface is a simple synchronous serial port with a single clock and single data line. Handling it with a microcontroller isn’t very difficult.

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Hackaday Prize Semifinalist: Bendy Solar Bluetooth Tags

Last January, [DrYerzina]’s sister couldn’t find her cat. The family searched the neighborhood for two hours until the cat came out from underneath a bed, proving once again cats own humans, not the other way around. A solution to this problem would come in the form of technology, specifically as [DrYerzinia]’s entry for the Hackaday Prize, a solar-powered Bluetooth tracking device. Yes, you can go on Amazon or eBay and buy a BLE tracker, but this version comes in a handy package: it’s built of a flexible circuit board to fit just about everywhere, including on the collar of a cat.

[DrYerzina]’s Bluetooth tracker is built around an Bluetooth LE module, with a few added passives, LEDs, and other parts glued and soldered onto a double sided, flexible PCB. To this, he’s added a flexible solar cell and a flexible LiPo battery. All of this is stuffed inside an enclosure 3D printed in flexible filament.

While the Hackaday Prize is filled with wearables, [DrYerzina]’s project is at the forefront of hombrew wearable technology. Nowhere else in the prize have we seen a dedication to making a device that bends. The best part is, he’s actually building a useful device; with just 15 minutes of sunlight a day (a condition very likely for a sleeping cat), this Bluetooth tag can work for weeks.

The 2015 Hackaday Prize is sponsored by:

Hipster Rotary Dial Adds Bluetooth 4.0

We have seen a few projects that convert a rotary dial for use with modern technology, but this one adds a new twist to the mix: it uses Bluetooth 4.0. [Silent] used a Nordic Semiconductor NRF51 DK development board for the project, which was built from the Nordic SDK source code for creating an HID (Human Interface Device). After what he claims was an hour or so of hacking, he was able to get this Arduino-compatible SoC dev board to detect the pulses from the rotary dial, then pass the appropriate number to a connected device as a key press. This means that his design should work with any device that has Bluetooth 4.0 support. It is powered from a big dry cell because, to quote [Silent], “small coin batteries are not hipster enough”.

It’s a simple project, and we have seen rotary cell phones before, but this still is ripe for expansion. You could either use a smaller, cheaper version of the Nordic chip at the center of this hack, as most of the dev board features aren’t used. Or you could do some more hacking, add support for the Bluetooth HSP headset profile, then wire it up to a vintage phone for the most hipster Bluetooth headset ever. We can’t wait until we see a hipster sitting in a coffee shop banging away on a typewriter and answering this. Get to it, people!

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Create a Buzz with the Mini Electric Ukulele

Everyone’s heard of the “World’s Smallest Violin,” but we think it’s time for something more upbeat. [Simone Giertz] of Punch Through Design has created a mini electric ukulele using a LightBlue Bean. The Bean is an Arduino-compatible microcontroller that you can wirelessly program using Bluetooth low energy (BLE).

The ukulele’s frame is made of laser-cut plywood.  Four 1M ohm resistors are soldered to individual wire strings. A different set of wire strings in the ukulele’s neck are connected to the same ground as the Bean. In order to play this tiny instrument, a finger must be kept on the “ground” strings while the other “tone” strings are touched by a different finger. [Simone] uses Arduino’s Capacitive Sensing Library to determine which string is being touched and what the tone will be (indicated in Hz). A piezo buzzer provides the sound. There is no need to fret when the battery is depleted from using this at an all-night luau: the frame can be unscrewed with easy access to the battery. [Simone] has uploaded the Bean’s code to GitHub.

There’s no shame going solo, but we’d enjoy a show of dueling mini-ukuleles. A duet with the 3D-printed ukulele is always a possibility. Or, play this little guy while running up and down some piano stairs while the kettle fife blows off some steam.  It’ll be a musical way to brighten anyone’s day. Check out the video of the mini ukelele after the break. You can also see more of [Simone’s] work at her website.

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Video Links: Hunting for Hacks at Maker Faire


Why not round out our two-week Bay Area Maker Faire coverage with a Links post? This time around it’s video links. We mixed together a bunch of interesting clips that didn’t get their own video, as well as a dose of what it feels like to walk around the Faire all weekend. Join us after the break for the links.

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Hackaday Links: October 20, 2013


Winter is coming. We’ve see those gloves in stores made specifically to work with your smartphone. [hardsoftlucid] isn’t buying it. He made his own version using… well, you just have to see it.

Here’s an eBookmark for a real book. What? Well, you know how an eReader does a great job of keeping your place between reading sessions? This is an electronic bookmark for paper books which uses LEDs to show you where you last left off reading. [via Adafruit]

[Thomas Brittain] wrote in to share his BLE Module and Pulse sensor updates. Both were featured in a recent Fail of the Week column and the latest iteration takes them from fail to functioning!

You may be able to get a free XMOS xCORE starter kit. The company is giving away 2500 of them. [Thanks Tony]

After learning about custom labels for microcontroller pinouts from [John Meachum] we’re happy to get one more helpful tip: a breadboard trench is a great place to hide axial decoupling capacitors.

A bit of cutting, solder, and configuring lets you turn a simple gamepad into a 4-controller interface for MAME.

Many of the Hackaday Staff are into Minecraft (between Let’s Play videos, running servers, and building computers in-game it’s a wonder we get anything done around here). We restrained ourselves by not making this video of a Restone circuit Blender animation on your desktop into a full front page feature. [via Reddit]


Sending data over Bluetooth Low Energy with a cheap nRF24L01+ module

nRF24L01+ modules like the one shown above are a great way to send data wirelessly between your projects. They can be found on many websites for less than $1.50

a piece and many libraries exist for them. After having thoroughly looked at the Bluetooth Low Energy (BLE) specifications, [Dimitry] managed to find a way to broadcast BLE data with an nRF24L01+.

Luckily enough, BLE and nRF24L01+ data packets have the same preambles. However, the latter can’t send more than 32bytes in a packet and can’t hop between frequencies as fast as the BLE specification wants. [Dimitry] found the solution when he discovered that he could send unsolicited advertisements on three specific channels. In the end, considering the 32 bytes the nRF24L01+ can send, you’ll need to use 3 bytes for the CRC, 2 for the packet header, 6 for the MAC address and 5 for devices attributes. This leaves us with 16 bytes of pure data or 14 bytes to split between data and name if you want your project to have one.