RP2040 microcontroller with 2MB of flash memory
On-board single-band 2.4GHz wireless interfaces (802.11n)
Micro USB B port for power and data (and for reprogramming the flash)
40 pin 21mmx51mm ‘DIP’ style 1mm thick PCB
Exposes 26 multi-function 3.3V general purpose I/O (GPIO)
23 GPIO are digital-only, with three also being ADC capable