I used nRF51822 processor based on ARM -M0, integrated Bluetooth function, onboard 5x5 LED dot , 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 various 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 Windows, macOS, iOS, Android and other operating ; The programming environment is based on web services, 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 CA variety of mainstream programming languages: TouchDevelop IDE BlocksCodeKingdoms JavascriptMicroPythonmbed enabledIn terms of hardware, my parameters are as follows:Nordic nRF51822Freescale KL26Z - 48 MHz ARM -M0+ core microcontroller16 MHz 32-bit ARM -M0 microcontrollerBluetooth 4.0 low energy/2.4GHz RF SoC16kB RAM256kB FlashCompass - Freescale MAG3110 3-axis Geomagnetic Sensor, I2C InterfaceAccelerometer - Freescale MMA8652 3-axis accelerometer, I2C interface connector - 3V supply interfaceReset button - reset button-USB connector - -USB interface, used to access computer programming, emulation programs, serial communication, etc.5x5 LED display - 5x5 LED dot , can display , graphics, etc. Button - Programmable buttonsI/O connection pins - I/O expansion interface, 20+5 expansion pins (including SPI, UART, I2C, Analog, PWM and other functionsColour: black blueMaterial: PCBPackage Contents:1 x development boardOnly the above package content, other products are not included.Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.