Hacking a Fitness Tracker

When [rbaron] started a new job, he got a goodie bag. The contents included a cheap fitness tracker bracelet that used Bluetooth LE. Since this is Hackaday, you can probably guess what happened next: hacking ensued.

For something cheap enough to give away, [rbaron] claims it cost $10, the device has quite a bit in it. In the very tiny package, there is an OLED display, a battery, a vibration motor, and a Nordic 32-bit ARM with BLE. The FCC ID was key to identifying the device. Opening the case, which was glued down, was pretty difficult, but doable with a hair dryer and a knife.

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Custom Firmware Unlocks Fitness Tracker

[Mikhail] sent us a teaser video for a hack he’d done (embedded below). He takes a Bluetooth LE fitness tracker dongle and reflashes it spit out the raw accelerometer data and trigger events. He then wrote a phone app that receives the data and uses the device as an alarm, an on/off switch, a data-logging device, and more.


We thought it was cool enough that we asked [Mikhail] for more detail, and he delivered in spades! Inside the device is a Nordic NRF51822, their ARM Cortex + Bluetooth chip, an accelerometer, and a bunch of LEDs. [Mikhail] mapped out the programming headers, erased the old flash, and re-filled it with his own code. He even added over-the-air DFU re-flashing capability so that he wouldn’t have to open up the case again.

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Federico Musto of Arduino SRL Shows Off New ARM-based Arduino Boards

I caught up with Federico Musto, President and CEO of Arduino SRL, at the 2016 Bay Area Maker Faire. Their company is showing off several new boards being prepared for release as early as next month. In partnership with Nordic Semi and ST Microelectronics they have put together some very powerful offerings which we discuss in the video below.

arduino-primo-core-alicepad-star-otto-lcdThe new boards are called Arduino Primo, Arduino Core, Arduino Alicepad, and Arduino Otto.

The first up is the Primo, a board built to adhere to the UNO form factor. This one is packing an interesting punch. The main micro is not an Atmel chip, but a Nordic nRF52832 ARM Cortex-M4F chip. Besides being a significantly fast CPU with floating-point support, the Nordic IC also has built-in Bluetooth LE and NFC capabilities, and the board has a PCB antenna built in.

On an UNO this is where the silicon would end. But on the Primo you get two more controllers: an ESP8266 and an STM32F103. The former is obvious, it brings WiFi to the party (including over-the-air programming). The STM32 chip is there to provide peripheral control and debugging. Debugging is an interesting development and is hard to come by in the Arduino-sphere. This will use the OpenOCD standard, with platformio.org as the recommended GUI.

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Micro:bit — BBC Gets A Million Kids Into Embedded Dev

In the Early 1980s, the BBC launched a project to teach computer literacy to a generation of British schoolchildren. This project resulted in the BBC Micro, a very capable home computer that showed a generation exactly what a computer could do. These children then went home, turned on their ZX Spectrums, and became a generation of software engineers. Still, the BBC Micro is remembered fondly.

The computer revolution is long over, but today we suffer a sea change of embedded processors and microcontrollers. With Arduinos and Raspberry Pis, the BBC has decided it’s time to put the power of an ARM microcontroller into the hands of a million 11- and 12-year olds. The result is the Micro:bit. It’s a small microcontroller board with an ARM processor, an IMU, buttons, Bluetooth and a 5×5 LED array – exactly what you need if you’re teaching a million kids how to blink an LED.

Although the BBC has finalized the design for the Micro:bit, there are no specs at all. However, a few educated guesses can be made. The USB controller is provided by Freescale, who also provide the digital compass and magnetometer. Programming is done through a web-based, Arduino-like IDE with what appears to be a decent Micro:bit specific library. The board is also mbed compatible. Bluetooth, and apparently the ARM Cortex M0 core, is provided by a Nordic nRF51822. There are only three alligator clip-compatible I/Os, and its doubtful any student will be building anything that would be too complex for an entry level ARM. It’s also 3V logic; finally, the tyranny of 5V has fallen.

The Micro:bit is best seen as a tool that enables the relatively recent addition of a computer science curriculum in UK schools. There is now a requirement for seven-year-olds to understand algorithms and create simple programs. Previously computer education in the UK has consisted of PowerPoint. Now, secondary school students will be learning Boolean logic.

While the Micro:bit is utterly useless as a tool for doing real work, education is not real work. For blinking a few LEDs, having a device react to movement, playing with Bluetooth, and other lesser evils of electronics, the Micro:bit is great. Not everyone will become the digital technologists this initiative is trying to create, but for those who have an inclination towards semicolons and electrons, this is a great introduction to technology.

New Part Day: Nordic’s New Bluetooth SoC

You don’t need to look very hard to find Nordic’s nRF51 wireless module; it’s found in hundreds of products and dozens of projects over on hackaday.io. The nRF51 is a SoC that includes an ARM Cortex M0 processor and a variety of radios for Bluetooth and other protocols. Useful, if a bit limited in processing power.

Now, Nordic has a new SoC. It’s the nRF52, a Cortex M4F processor, a Bluetooth radio, NFC, and a bunch of Flash and RAM to make just about anything you can think of possible. Yes, it’s an upgrade to the nRF51 – a better processor and NFC, and all the possibilities that come with that. Currently there’s only one part and two package options: a 6x6mm QFN48, or a wafer chip that will be covered with impregnable goo.

Already there are SDKs for IAR Workbench, Keil4 and 5, and gcc. The SDKs won’t help you quite yet; it’s not available through the usual distributors yet, but the nRF52 Preview develoment kit is. That’s a single board development kit for the nRF52, with Arduino pinouts and Mbed support.

Thanks [Alvin] for sending this in from Trondheim.

THP Semifinalist: NoteOn Smartpen

There are a ton of apps out there for taking notes and recording ideas, but sometimes the humble pen is best. However, if you have the tendency to lose, crumple, or spill caffeinated beverages on your pen and paper notes, having a digital copy is quite nice.

The NoteOn Smartpen by [Nick] aims to digitize your writing on the fly while behaving like a normal pen. It does this by using the ST LSM9DS0TR: a 9-axis inertial measurement unit (IMU). These inertial measurements are processed by a STM32 Cortex M4F processor and stored on the internal flash memory.

To retrieve your notes, the Nordic nRF8001 Bluetooth Low Energy radio pairs the MCU with a phone or computer. The USB port is only used to charge the device, and the user interface is a single button and LED.

The major hardware challenge of this device is packaging it in something as small as a pen. Impressively, the board is a cheap 2 layer PCB from OSHPark. The assembled device has a 10 mm diameter, which is similar to that of ‘dumb’ pens.

The NoteOn doesn’t require special paper, and relies only on inertial measurements to reconstruct writing. With the hardware working, [Nick] is now tackling the firmware that will make the device usable.

SpaceWrencherThe project featured in this post is a quarterfinalist in The Hackaday Prize.

THP Quarterfinalist: WALLTECH Smartwatch

While there is lots of hype about a big company launching a new wearable product, we’re more interested in [Walltech]’s open source OLED Smartwatch. This entry into The Hackaday Prize merges a collection of sensors and an OLED screen into a wearable device that talks to your smartphone over Bluetooth Low Energy.

The device is based on the IMUduino BTLE development board. This tiny Arduino clone packs an inertial measurement unit (IMU), a Nordic nRF8001 Bluetooth radio, and an ATMEGA32u4 microcontroller.

The 1.5″ OLED display comes from [miker] who makes an OLED module based on the SSD1351. A STP200M 3D pedometer provides activity monitoring in a tiny package.

On the hardware side, packaging all these components into something that will fit on your wrist is quite difficult. The prototype hardware is built from mostly off the shelf components, but still manages to be watch sized.

At this point, it looks like the code is the main challenge remaining. There’s a lot of functionality that could be implemented, and [Walltech] even mentions that it’s designed to be very customizable. It even supports Android; the Apple Watch can’t do that.

SpaceWrencherThe project featured in this post is a quarterfinalist in The Hackaday Prize.