3D Printed RGB LED Bracelet


[Marcus's] 3D-printed LED bracelet has moved through a number of revisions recently, but each iteration is impressive in both simplicity and functionality. Inspired to experiment with his print of [nervoussystem's] Diagrid Bracelet, [Marcus] took the opportunity to add some LEDs with his first build, which combined a strip of RGB LEDs, a small battery, and an Adafruit Trinket microcontroller.

A second build soon followed, which overhauled the bracelet’s design into a more solid form and managed to double the amount of LEDs by upgrading to a different strip. The bracelet is currently in its third revision, cycling through the spectrum for around 3.5 hours on a single charge. This build also sports a 3-axis accelerometer: when the wearer shakes the bracelet, the colors skip around. If shaken long enough, the bracelet will enter a dazzling flurry of color flickering. Stick around after the break for a few demonstration videos. If you want to print your own, head over to [Marcus's] Thingiverse file.

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Wristband RFID unlocks car door and starts engine

[João Ribeiro] is an electronics engineer by day, but in his free time he likes to ply his trade on everyday items. Recently he’s been integrating his own microcontroller network to unlock and start his car via RFID. In addition to the joy of pulling apart the car’s interior, he spent time designing his own uC breakout board and developing an RFID reader from a single chip.

He’s working with a 1988 Mercedes that has very little in the way of electronics. It sounds like the stock vehicle didn’t even include a CAN bus so the prelude to the RFID hack had him installing a CAN bus network made up of two microcontrollers. One reads the velocity and RPM while the other displays it on the tachometer. When he began the tag-based entry system he used an RFID reader module for prototyping, but eventually built his own reader around the TRF7960 chip. This included etching his own receiver coil which was mounted in the side-view mirror bracket. To unlock the doors he holds the bracelet up to the mirror and the vehicle lets him in. The video after the break starts with a demonstration of the completed project and moves on to some build videos.

We certainly like the idea of using a bracelet rather than implanting the tag in the meaty part of your hand.

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See in the dark with this bracelet build

Even though she’s only in 8th grade, [Hannah Prutchi] is turning into a very respectable builder. She designed SharkVision, a wearable distance sensor that is meant to help the blind find objects they might bump into.

The SharkVision gets its name from shark’s ability to ‘see’ prey in their surroundings by sensing the local magnetic field. Instead of building her own Ampullae of Lorenzini, [Hannah] decided to take the easy route and use a few infrared sensors mounted to a bracelet. Whenever something is picked up by the proximity sensor, a voltage is applied to a pager motor telling the wearer they’re about to run into something.

[Hannah] and her classmates have successfully tested the SharkVision bracelet by walking around their classroom with eyes closed. They didn’t bump into anything, a fact [Hannah] attributes to neuroplasticity. We think it’s a neat build, but we’re wondering if this could be given to a population of blind people.

Bluetooth bracelet hacked

[Jeffery] hacked the Bluetooth standard in order to use this bracelet as a custom display. He took up our challenge to hack the device when we first saw it back in February.

In order to display his own messaged he looked into how the HFP is implemented in the Bluetooth stack. The details are shared in his readme file but it goes something like this: The Bluez package needs to be compiled with a dummy backend that is not phone-specific and that will then allow external manipulation of the data being sent. This provides something of an API that a Python script can manipulate. His proof-of-concept allows for the script to be called with the message you want displayed as the command line argument. This should be simple enough to incorporate for just about any purpose that suits your fancy. Unfortunately, messing with the Bluetooth package in this way makes it impossible to use other devices with your phone, but that’s a hack for another day.

Hackit: Hackable Bluetooth bracelet?


We spotted this odd piece of geek couture on DVICE today. It’s a bracelet that displays incoming calls via Bluetooth and also vibrates. The intended use is kinda interesting, but we wonder what else could be done with it. Could you update it with any text you want by creating fake caller ID messages? You could have your laptop in your backpack and have the bracelet update when it finds an open access point or any other sort of notification. The display shows the word “Connecting” in pictures, but apparently only displays numbers for incoming calls. It also includes a button to reject calls.

Do you have a project that needs a wireless display? Are there other options like this? At $25, this might be worth a try.