Available to order as a PCB from OSH Park or a completed unit from Tindie, this compact Arduino-compatible aims to make BLE a cinch.
PeskyProducts and Tlera Corp have designed an open-hardware development board for Bluetooth Low Energy (BLE) projects, built around STMicro’s STM32 microcontroller and boasting full Arduino IDE support: the Firefly BLE.
“This is a small, open source hardware implementation designed to make using and customizing the STM32WB55 easy for everyone,” Tlera Corp explains of the Firefly BLE’s design. “It supports iBeacon, NUS, BlueST protocols as well as standard and custom BLE services and characteristics.
“For several years we have been making use of ST’s STM32L4 family of ultra-low-power MCUs in a variety of applications including development boards, asset trackers, and environmental monitors. Often we include a BMD-350 (nRF52) module for BLE connectivity with smart devices like Android and IOS phones, etc. With the new dual core STM32WB55 MCU, we can now make devices similar in cost, size, and functionality to those we have been but also have the added benefit of embedded BLE connectivity.”
Hi! My name is Nisha, and I made a party bangle for my friend, Miki, to take with her to DefCon25. It was my first fully-formed electronics project and it posed some interesting challenges due to its unusual form factor. You can read about my experiences with that project here.
Soon after DefCon25, I was approached by r00tkillah to make over a 100 of something similar for the DC503 party at DefCon26. The plan was to combine the power of the BMD-300 SoC by Rigado used in the Wagon Badge from the previous year with my Neopixel bangle form factor. We would call it “The Banglet” and it was going to be awesome.
In passive mode, the banglet’s LEDs light up when detecting nearby Bluetooth devices. The number of LEDs that are lit correspond to the number of BT devices detected and their colors are based on each device’s mac address.
This is a 20 mm x 20 mm four-layer pcb tile full of interesting sensors (ICS43434 I2S Digital Microphone, MPU6500 acclerometer/gyro, BME280 pressure/temperature/humidity, and CCS811 air quality) with a Rigado BMD-350 UART BLE bridge for sending data to a smart phone all managed by a STM32L432 host MCU.
The STM32L432 is programmed using the Arduino IDE via the USB connector and serial data can be displayed on the serial monitor to verify performance and proper function, etc. But it is intended to be powered by a small 150 mAH LiPo battery for wireless sensing applications. The STM32L4 is a very low power MCU and with proper sensor and radio management it is possible to get the average power usage down to the ~100uA level, meaning a 150 mAH LiPo battery can run the device for two months on a charge.
A collection of sketches to run the STM32L432-based (20 mm x 20 mm) sensor tile with an MPU6500 accel/gyro, ICS43434 I2S digital microphone, BME280 temperature/pressure/humidity sensor, and CCS811 air quality sensor. The sensor tile has an on-board MAX1555 LiPo battery charger, an on/off switch, and a Rigado BMD-350 nRF52 BLE module.
The idea is that a blind person uses a navigation app, and can query to see “what is around”. In the list of beacons that are around, they can tap the one they want to know the location of and it will start to produce an audible signal for a short time.