Lemon Wireless Microcontroller

Read more on the Lemon Microcontrollers homepage.

I took everything you could possibly want in your wireless microcontroller and stuck it on a PCB:

• An nRF52840 microcontroller (Bluetooth and BLE, UF2 bootloader)
• FPC Connectors to connect Pumpkin Flex PCBs or TheBigSkree's fully flexible PCBs 
• A VIK connector for connecting VIK-compatible trackballs and displays (or to use with my VIK breakout)
• Through hole pads for alternatively soldering connections to your keys or accessories
• Power on/off switch
• JST connector for batteries
• Battery charging circuitry with 500mA fast charge mode
• Onboard RGB LED to show bootloader status
• Level shifting to drive LEDs at 5V when plugged in or battery power
  
• Supports firmware autogen in Cosmos

If you're using the Lemon with a trackball or display that doesn't have a VIK connector, you can use the VIK breakout board I sell to add one right next to the peripheral and a 12p 0.5mm FPC cable to neatly connect to the microcontroller.