Accessing Hardware Features

This is an Open Source Hardware project. Schematics and board design files are available in the /hardware directory of the repo.

The badge uses the same core module as the Puck.js and can run most of the same software.

Hardware Features include:

  • nRF52832 SoC - 64MHz ARM Cortex M4, 64kB RAM, 512kB Flash, running the Espruino stack
  • Bluetooth Low Energy
  • Powered by a CR2032 battery which can last up to a week depending on what code you are running
  • Daylight-readable LCD screen
  • 6 input buttons
  • Capacitive touch sensors on all 6 corners
  • Digital I/O on all 6 corners
  • Analogue-in on 3 corners
  • Prototyping area with 8 CPU pins accessible
  • Digital I/O on all 8 pins
  • Analogue-in on 4 pins
  • Holes for LEDs on all 6 corners
  • NFC antenna
  • SWD programming pins

Proto holes and corner holes

You write or read a digital high/low to/from a hole with:

digitalWrite(hole, value);

where hole is one of D0, D1, D2, D3, D4, D5, D6, D7, D8 (D0 at top), CORNER1, CORNER2, CORNER3, CORNER4, CORNER5, CORNER6 and value is 0 or 1.

You read an analogue value from a hole with:


where hole is one of D2, D3, D4, D5, CORNER4, CORNER5, CORNER6.


You can use a generic call like


where button is one of BTNA, BTNB, BTNU, BTND, BTNL, BTNR

or with a Button-specific call;

where BTNx is one of BTNA, BTNB, BTNU, BTND, BTNL, BTNR


If you add LEDs to the corner holes, you can turn them on/off with a generic call

digitalWrite(led, value);

where led is one of LED1, LED2, LED3, LED4, LED5, LED6.

or with an LED-specific call


where LEDx is one of LED1, LED2, LED3, LED4, LED5, LED6 and value is 0 or 1.


In many Espruino examples on the main site, you’ll find setup code for different types of screens. That has already been taken care of for you on the badge and you can just access the graphics functions directly. e.g.

g.drawString("Hello World",0,0);

Capacitive Sense

You can read the capacitance (and hence touch) from the 6 corners using


where corner is one of CORNER1, CORNER2, CORNER3, CORNER4, CORNER5, CORNER6. See note here about issue of using sense and LEDs together.

Battery Percentage

You can get an estimate of the battery level by calling


It returns an approximate battery percentage remaining based on a normal CR2032 battery (2.8 - 2.2v).

Set Screen Contrast

You can set the screen contrast with


where c is a float from 0 to 1


You can set the URL that the NFC antenna broadcasts to NFC-capable phones by calling


where URL is something like

Advanced Only: Flashing updated firmware

If you need to flash new firmware to the badge, you must first put it in DFU mode by holding BTNA as you insert the battery and quickly letting go of BTNA. Download the Distribution Packet Zip file containing the new firmware to your phone and use nRF Toolbox on either Android or iOS to send it to the badge.

Please only do this if you are sure you need it. By using a stock badge build from the Espruino site, you’ll lose the built-in NodeConf EU main.js code and will just have a REPL over Bluetooth on your badge.