Node and receiver node are the same hardware - so just one board design.

Core functionality

  • small
  • low cost
  • reliable bidirectional wireless communication
  • multiple nodes
  • standardized headers

Usable for:

  • sensing
  • actuation
  • transceiving (data I/O to other boards, e.g. another embedded computer, or a more powerful microcontroller)

The main features are an onboard 9 degrees of freedom sensor and a high resolution (16bit) 4 channel ADC. The power input options will be improved, there will be an onboard charger, and it is possible to use the board also wired via usb. The board will have an open source RF-capable microcontroller - so no need for an XBee anymore. This will bring the cost price down by half.

Hardware in detail


  • onboard 9 d.o.f. (accelerometer, gyroscope, magnetometer)
  • 16 bit 4-channel ADC

power input

  • battery JST (market standard)
  • USB (e.g. usb power bank)
  • 2 pins - that can be wired up (Vraw)
  • li-ion battery does not need to be there
  • reverse polarity protection
  • resetting fuse

battery management

  • Built-in charger
  • battery level indicator (i2c)
  • exchangeable battery

power regulation

  • enough mA on regulator to also power sensors
  • steady regulator - linear; doesn’t have dips
  • 3.3 V - 500 mA
  • lipopi - inspiration: - though this may be an overkill

power switch

  • soft / pushbutton approach
  • pins exposed to user - so that it can be a different button, embedded in the object
  • edge button : squeeze

on board leds

  • power - physical (is the regulator on)
  • charging
  • status (rgb)
  • rf transceiver status (pin PF3)
  • rx/tx to usb - flashing lights when communication happens


  • two mounting holes, or
  • fancy sturdy velcro like pinoccio, or
  • dents to click it into something

plug in usb

  • reprogram
  • data communication-standalone use
  • power and/or recharge


  • external antenna possible: uFL connector
  • pcb antenna
  • little solder jumper to switch between the two


  • standard MHz on clock (firmware compatibility) = 16 MHz for our chip
  • sense USB connection

extension board

  • prototyping board and have an edge connector
  • breadboard extension

pin configuration for header

pin configuration (18 pins)

*bottom*               *top*
Vraw (Vin)         --- PWR GND
power/3v3/Vreg     --- PWR button
D0                 --- sig gnd
D1                 --- analog 0
D2                 --- analog 1
D3                 --- analog 2
D4                 --- analog 3
RX                 --- SDA
TX                 --- SCL
  • 5 digital : possibly a neopixel RGB : at least three that do PWM
  • 4 analog - through ADC - ADS1115 : maybe multiplex with digital ports