This board has the same basic Bluetooth LE module that we use on Puck.js and Pixl.js, pre-programmed with Espruino, however instead of an onboard ceramic antenna, it has a connector for an External u.FL 2.4GHz antenna. (Click here for the ceramic antenna version)

With and external antenna we've seen increases in dBm readings within Espruino of between 5 to 20 dBm, and significantly more devices found when scanning.

This board does not come with an antenna. While it is can be used/connected to without one, it is not recommended! You'll need a 2.4GHz u.FL antenna. The ones recommended by Raytac are:

• Yageo ANTX100  ETHAB24553 (External)
• Yageo ANTX200 P001B24003 (PCB)
• Yageo ANTX100 P111B24003 (PCB)

We sell pre-programmed bare modules, but this is a board with 0.1" pins, a voltage regulator, 2 LEDs and a button. It's thin, small, and very power efficient.

Features

• Bluetooth Low Energy
• Espruino JavaScript interpreter pre-installed
• nRF52832 SoC - 64MHz ARM Cortex M4, 64kB RAM, 512kB Flash
• 22 GPIO (capable of PWM, SPI, I2C, UART) on 0.1" pitch, including 7 analog inputs
• Built in thermometer
  
• NFC tag programmable from JavaScript (when antenna added)
• 2.5v  - 16v input voltage range, drawing ~20uA while advertising.
• Powerful (250mA, 500mA peak) MCP1703T 3.3v voltage regulator, capable of powering an ESP8266
• Dimensions: 18mm x 28mm x 4mm thick
• Click here for full technical information
• MDBT42's Certifications are listed on espruino.com