I used nRF51822 processor based on ARM -M0, integrated Bluetooth function, onboard 5x5 LED dot matrix, two programmable buttons, accelerometer, three-axis geomagnetic and thermometer and other resources. I also introduced a 20+5pin extension interface, which can easily be used for programming-related teaching and development scenarios, including programming , robot control, scientific experiments, and wearable device development; I'm only half the size of a credit card (4cm x 5cm), and you can integrate me into many portable projects. In terms of software, I support the PXT graphical programming interface developed by : Support , macOS, iOS, Android and other operating systems; The programming environment is based on web , no additional compiler downloads are required; Computer programming and emulation program via USB; The mobile terminal wirelessly writes and emulates the program through Bluetooth; I also support Javasript, Phython, Mbed C A of mainstream programming languages: TouchDevelop IDE Blocks CodeKingdoms Javascript MicroPython mbed enabled In terms of hardware, my parameters are as follows: Nordic nRF51822Freescale KL26Z - 48 MHz ARM -M0+ core microcontroller 16 MHz 32-bit ARM -M0 microcontroller Bluetooth 4.0 low energy/2.4GHz RF SoC 16kB RAM 256kB Flash Compass - Freescale MAG3110 3-axis Geomagnetic Sensor, I2C Interface Accelerometer - Freescale MMA8652 3-axis accelerometer, I2C interface Power connector - 3V power supply interface Reset button - reset button Micro-USB connector - Micro-USB interface, used to access computer programming, emulation programs, serial communication, etc. 5x5 LED display - 5x5 LED dot matrix, can display text, graphics, etc.Button A/B - Programmable buttons I/O connection pins - I/O expansion interface, 20+5 expansion pins (including SPI, UART, I2C, Analog, PWM and other functions Colour: black blue Material: PCB Package Contents: 1 x development board Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.