Which Wireless Tech is Right For You?

It seems these days all the electronics projects are wireless in some form. Whether you choose WiFi, Bluetooth Classic, Bluetooth Low Energy, ZigBee, Z-Wave, Thread, NFC, RFID, Cell, IR, or even semaphore or carrier pigeon depends a lot on the constraints of your project. There are a lot of variables to consider, so here is a guide to help you navigate the choices and come to a conclusion about which to use in your project.

We can really quickly reduce options down to the appropriate tech with just a few questions.

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Add Bluetooth to a Cheap Electronic Lock

[James] works from home. His office is filled with objects that can be described with adjectives such as, “expensive,” and, “breakable.” His home, however, is filled with professional object-breakers known as children. To keep these two worlds from colliding, he installed a keypad lock on his office door. The potential side-effect of accidentally training his children to be master safe-crackers aside, the system seems to work so far.

However, being a hacker, the tedium of entering a passcode soon grew too heavy for him. Refusing to be a techno-peasant, he set out to improve his lock. The first step was to reverse engineer the device. The lock is divided into two halves, one has a keypad and handle, the other actually operates the lock mechanism. They are connected with a few wires. He hooked an oscilloscope to the most likely looking candidates, and looked at the data. It was puzzling at first, until he realized one was a wake-up signal, and the other was the data. He then hooked the wires up to a Bluetooth-enabled Arduino, and pressed buttons until he had all the serial commands the door lock used.

After that it was a software game. He wrote code for his phone and the Arduino to try out different techniques and work out bugs. Once he had that sorted, he polished the app and code until he reached his goal. All of the code is available on his GitHub.

Finally, through his own hands, he elevated himself from techno-peasant to wizard. He need but wave his pocket oracle over the magic box in front of his wizard’s lair, and he will be permitted entry. His wizardly trinkets secure from the resident orcs, until they too begin their study of magic.

Bluetooth Water Cannon Junk Build Shoots Into Our Hearts

We’ve seen a few remote controlled turret builds in the past, but this one from [Noel Geren] is pretty neat: it shoots water and uses Bluetooth Low Energy (BLE) for control. Check it out in action in the video below.

[Noel] used the guts of a Nerf Thunderstrike water gun for the firing mechanism, combined with a 3D-printed enclosure and a servo that rotates the turret top. The pump from the gun is connected to a simple relay that replaces the trigger. Both the relay and the servo are connected to an RFDuino with a servo shield, which is programmed to respond to simple commands to rotate and fire.

It’s a nice junk build, and [Noel] has released all of the files for download if you want to build your own. It would make a nice weekend build or a project to do with the kids.

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Minions Turn Your Keyboard into a Bluetooth Keyboard

Evil geniuses usually have the help of some anonymous henchmen or other accomplices, but for the rest of us these resources are usually out of reach. [Evan], on the other hand, is on his way to a helpful army of minions that will do his bidding: he recently built a USB-powered minion that turns a regular PS/2 mouse and keyboard into a Bluetooth mouse and keyboard.

[Evan] found his minion at a McDonald’s and took out essentially everything inside of it, using the minion as a case for all of the interesting bits. First he scavenged a PS/2 port from an old motherboard. An Arduino Nano is wired to an HC-05 Bluetooth chip to translate the signals from the PS/2 peripherals into Bluetooth. The HC-05 chip is a cheaper alternative to most other Bluetooth chips at around $3 vs. $40 for more traditional ones. The programming here is worth mentioning: [Evan] wrote a non-interrupt based and non-blocking PS/2 library for the Arduino that he open sourced which is the real jewel of this project.

Once all the wiring and programming is done [Evan] can turn essentially any old keyboard and mouse into something that’ll work on any modern device. He also put an NFC tag into the minion’s head so that all he has to do to connect the keyboard and mouse is to swipe his tablet or phone past the minion.

If you’re looking for an interesting case for your next project, this McDonald’s Minion toy seems to be pretty popular. PS/2 keyboards are apparently still everywhere, too, despite their obsolescence due to USB. But there are lots of other ways to get more use out of those, too.

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Put Words in Your Dog’s Mouth With A Talking Dog Collar

It’s just a little past Halloween, but Adafruit’s talking dog collar, modeled after the movie Up, is still a nice fusion between crafting and hacking.

One reason that Adafruit is so popular is that every time they sell us something, they give us some of the worlds best tutorials and libraries for free. For this project they’re using their Bluetooth LE board and their Audio FX board with a few more mundane vitamins to construct the collar. We’re sure the enterprising hacker could find alternatives if they so choose.

The collar is made of leather and 3D printed props. They went with alkaline batteries rather than lithium, to keep their doggy companion a little safer. All the electronics are hidden under the various props and the wiring is routed behind the belt. To control the app, the different sound bytes are mapped to buttons on their Bluetooth-to-serial phone app.

It’s a good starter tutorial, and the concept applied differently would definitely be good for at least one good prank on a coworker or friend.

 

Tiny BLE UART Makes Bluetooth Low Energy Simple

Last time I talked about the internals of how Bluetooth Low Energy (BLE) handles data. I mentioned that the way it is set up is meant to conserve power and also to support common BLE devices like heart rate monitors. On the other hand, I also mentioned that you often didn’t need to deal with that because you’d use an abstraction layer.

This time, I want to show you how I used the Hackaday special edition Tiny BLE (from Seeed Studios) and its mbed library to do a quick simple BLE project. If you didn’t read the first part, don’t worry. The abstraction is so good, you probably won’t have to unless you want to circle back around later and get a more detailed understanding of what’s happening under the covers.

I wanted something simple for an example so you could build on it without having to remove much code. For that reason, I decided to allow my phone to control the state of a three-color LED via BLE. To do that, I’m going to use a virtual UART and some off-the-shelf phone software. The whole thing won’t take much code, but that’s the point: the abstraction makes BLE relatively simple.

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Lazy Bluetooth: Build with BLE, Don’t Reinvent It

It is a good bet that you have at least one Bluetooth device hanging around. Headsets, mice, keyboards, and speakers have become increasingly common. Bluetooth forms a short range wireless network and can also perform file transfers and create virtual serial ports.

If you have ever had to stop listening to music to recharge a Bluetooth headphone, you know Bluetooth won’t run long on batteries. In 2006, Nokia introduced Wibree, which would later become Bluetooth Low Energy (or BLE). These days it’s used in everything and it’s well worth your time to gather a basic understanding of this technology.

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