[Harris Shallcross] decided to build a pair of smart glasses and recently completed a first prototype of his project ‘Ochi’ – an STM32 based, BLE-connected, OLED eyeglass display. There are of course several homebrew smart glasses projects out there; many are more polished-looking and nearly all of them also display information from a smartphone over Bluetooth. This one is interesting partly because it highlights many of the design challenges that smart glasses and other near-eye displays face. It also demonstrates the iterative development process: begin by getting something working to learn what does and doesn’t cut it at a basic level, and don’t optimize prematurely; let the process bring problems to the surface.
For his project, [Harris Shallcross] used a small 0.95″ diagonal 96×64 color OLED as the display. The lens is from a knockoff Google Cardboard headset, and is held in a 3D printed piece that slides along a wire rail to adjust focus. The display uses a custom font and is driven by an STM32 microcontroller on a small custom PCB, with an HM11 BLE module to receive data wirelessly. Power is provided by a rechargeable lithium-ion battery with a boost converter. An Android app handles sending small packets of data over Bluetooth for display. The prototype software handles display of time and date, calendar, BBC news feed, or weather information.
Devices like these have a lot to deal with. Weight and distribution of that weight is a concern, the size and comfort of the optics is important, and displaying data on a small OLED is only part of the battle – choosing what information to display and when are vital to the device being actually useful in any way, otherwise it’s just a tech demo.
This project set out to show whether it was possible to use the parts listed to make a glasses mounted smart display that was at least somewhat functional, and the software to support it. Clearly, [Harris Shallcross] succeeded at that, but what really showcases the development process is his list of improvements – what he decided needs to go into a second version, and why. One of those goals is to improve the optics; perhaps there’s something to learn from The $60 Bluetooth Head Mounted Display project, which used a similar OLED and a prism to locate the display off to the side instead of in front.
While faking BLE advertising beacons using an nRF24L01+ module is nothing new, it’s become a heck of a lot easier now that [Pranav Gulati] has written some library code and a few examples for it.
[Pranav]’s work is based on [Dmitry Grinberg]’s epic bit-banging BLE research that we featured way back in 2013. And while the advertisement channel in BLE is limited in the amount of data it can send, a $1 nRF24 module and a power-thrifty microcontroller would be great for a battery-powered device that needs to send small amount of data infrequently for a really long time.
We’re not 100% sure where [Pranav] is going to take this project. Honestly, the library looks like it’s ready to use right now. If you’ve been holding off on making your own BLE-enabled flock of birds, or even if you just want to mess around with the protocol, your life has gotten a lot easier.
There is a lot of spectacle on display at Maker Faire. But to be honest, what I love seeing the most are well-executed builds pulled off by passionate hackers. Such is the case with [Debra Ansell]. She wasn’t exhibiting, just taking in all the sights like I was. But her bag was much better than my drab grey camera-equipment filled backpack; she build a handbag with an LED matrix and did it so well you will scratch your head trying to figure out if she bought it that way or not.
Gerrit and I walked right up and asked if she’d show it to us. We weren’t the only ones either. [Debra’s] bag started drawing a crowd as she pulled out her cellphone and sent “Hackaday” to the 10×15 matrix over Bluetooth. Check out our video interview below.
Continue reading “Exquisite LED Handbag in the Wild”
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.
Continue reading “Bluetooth Water Cannon Junk Build Shoots Into Our Hearts”
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.
Continue reading “Tiny BLE UART Makes Bluetooth Low Energy Simple”
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.
Continue reading “Lazy Bluetooth: Build with BLE, Don’t Reinvent It”
With the launch of the Raspberry Pi 3, Bluetooth Low Energy (BLE) is now at our disposal. With BLE, there are a few technologies for implementing one-way beacons that broadcast data. Apple has been pushing iBeacon since 2013, and Google just launched their Eddystone solution last year.
If you’re looking to target Google’s Eddystone on your RPi 3, [Yamir] has you covered. He’s put together a guide on setting up an Eddystone-URL beacon within Raspbian. This type of beacon just broadcasts a URL. Users within range will get a notification that the URL is available, and can navigate through to it. Eddystone-URL works on both iOS and Android.
The process for setting this up is pretty simple. The
hcitool commands do all the work. [Yamir] was even nice enough to make a calculator tool that generates the
hcitool command for your own URL. While is hack is a simple one, it’s a nice five-minute project. It’s also handy for broadcasting the URL of your Raspberry Pi if it’s running a web server as part of a more intricate hack.