This expansion board is compatible with and control boards and two kinds of motherboards.Insert the control on the front and the on the back. It leads out 10 digital/analog 3Pin ports, two IIC ports UART port; on-board two motor drivers, and does not occupy extra pins;On-board PH2.0 and -USB two supply ports, which can be powered by usb cable or It can be powered by the battery box or lithium battery, the supply voltage is 3.5-5V, the on-board switch can switch the external supply;There is a high-quality buzzer on the board, and with switch control, the buzzer can be turned off at any time; led out 9 1 clip interface; compatible with control finger and finger. The expansion board is compatible size holes and can be combined.Technical Specifications1. External 3 AA dry batteries (3.5V~5V) or 3.7V lithium battery, PH2.0 interface2, USB interface external supply (3.5V~5V), -USB interface3. supply of the control board (Note: Due to the limited driving capability of the IO port of the control board, the control board is used for supply and cannot drive high- peripherals. If you need to use motors and other equipment, please use an external battery or an external USB port for supply)4. IO port: P0 P1 P2 P8 P9 P12 P13 P14 P15 P165. I2C interface x26. Serial port x1 (P13 P14)7. Pin gold finger: 0 1 2 3V GND8. Touch gold finger x 6: P Y T H O N (exclusive to control)9. Microbit buzzer x 1 P0 port (for microbit)10. Buzzer switch x 111. Motor drive x 212. Gold finger aperture: 4.8mm compatible with 13. Gold finger hole distance: 8mm compatible with 14. Bottom black acrylic protectionColour:blackMaterial:plasticSize:8 x 5cmPackage Contents:1 * master I/O expansion 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.