microcontroller, 256 KB flash memory, 16 KB static ram, 2.4 GHz Bluetooth low energy wireless networking. 4 NXP/Freescale KL26Z – 48 MHz ARM Cortex-M0+ core microcontroller, that includes a full- speed USB 2.0 On-The-Go (OTG) controller, used as a communication interface between USB and main Nordic microcontroller. 4 NXP/Freescale MMA8652 – 3-axis accelerometer sensor via I²C-bus. 4 NXP/Freescale MAG3110 – 3-axis magnetometer sensor via I²C-bus (to act as a compass and metal detector). 4 MicroUSB connector, battery connector, 25-pin edge connector. 4 Display consisting of 25 LEDs in a 5×5 array.[13] 4 Three tactile pushbuttons (two for applications, one for reset). Ladislav Prskavec - Golang Prague #4, 4th Sep 2019 6