Blidgets is a platform I created to prototype wearables, smart objects and other wireless devices. It consists of small core modules that provides wireless connectivity via Bluetooth LE and pluggable extensions that allow to add functions easily. Breadboard compatible connectors also enable the fast creation of custom extensions.

I got the idea for this platform when I started to build a BLE version of the belt worn badge in 2013. Back then, there was no platform with BLE support available and tiny prototyping boards (suitable to build small wearables) were also rare. So I started to build my own PCBs for the nRF51822 chipset by nordic semiconductor. I got some help from Christian Weichel for the first revision and feedback from Thomas Kubitza. It took 3 PCB revisions to reach the final form factor.

To make prototyping with the Blidgets faster, I also created a number of stackable extensions with commonly used sensors and actuators, like a buttons, LEDs, motion sensors, etc. (a full list of extension modules can be found below). To support sensors and actuators requiring more current than a coin cell can deliver, I designed several power supply extensions. Later I added modules with gadgeteer and xadow compatible connectors to leverage from the growing variety of extensions available for these platforms.

Blidget with extension modules
Blidget with extension modules

To allow users to get started quickly I wrote a generic firmware for the core module. This enables to connect and control a Blidget and its attached modules without the need to program and flash a firmware first. To cope with the vast variety of extension modules and custom setups the platform was designed to be used with, the generic firmware supports all GPIO pin modes and bus protocols the microcontroller offers. Any possible combination of pin usages can be configured over the air on runtime, for example by using the meSchup server. Additionally (for the advanced user), there is the possibility to program and flash a custom firmware via Bluetooth LE.

To give Bligdets a nice look and feel, I designed and 3d printed several enclosures for different configurations and presentations of the Blidget platform.

Blidget with keyfob enclosure
Keyfob enclosure

Technical facts

  • Based on the nRF51822
    • 16MHz, 16kb RAM, 256kb Flash
    • Bluetooth LE connectivity
  • Very small form factor (25mm x 25mm)
  • Low energy consumption (~ 0.03mA)
    (allows a prototype to run up to a year from a coin cell)
  • Handy extension for commonly used sensors and actuators
  • 18 GPIO ports for custom extensions, supporting:
    • digital in and out
    • analog in
    • PWM, SPI, TWI and UART
Extension modules
  • sensors: button, potentiometer, joystick, light, infrared, motion (accelerometer and gyroscope)
  • actuators: infrared, notification (RGB LED, buzzer and vibration motor)
  • adapters: gadgeteer, xadow
  • power: LiPo, USB, smart (toggles power on motion)

Blidgets – A Bluetooth Low Energy prototyping platform
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