Usage: TelecommunicationVoltage: 5VPower Source: DCTheory: bluetooth relayLC 12V Bluetooth 4-channel relay module equip with SPP-C Bluetooth 2.1 slave module and 8 bit high percompatible withmance MCU, you can control the relay with cellphone APP directly.Protect Feature: EpoxyContact Load: Low PowerModel Number: bluetooth relay moduleThe function and characteristics:1, On-board N76E003/STM8S003 and SPP-C Bluetooth 2.1 module2, The relay can be controlled with APP3, Effective control distance(on open area): 10m4, Power supply: 12V5, On-board 12V, 10 A / 250 v AC 10 A / 30 v DC relay, absorb 100000 timescontinuously, Module with diode effusion protection, short response time6, On-board optocoupler isolation components, anti-interference ability is strongly7, On-board Bluetooth indicator and relay indicator LED8, On-board preserved UART debug interface(Baud rate is 9600) and MCU program interfaceInterface:IN+, IN-: 12V power inputTX, RX: UART communicationSWIM, NRST: MCU program interfaceLED D2/D3/D4/D5(red): Relay indicatorLED D1(blue): Bluetooth state indicator, the of D1 as below:(1)Its means wait compatible with establishing connection with the APP when D1 blink slowly(2)Its means the Bluetooth connect with the APP successfully when D1 on all the timecolour:blueMaterial:PCBsize:62.7*63.2mmPackage Contents:1 * 12V 4CH Remote Control Switch ModuleOnly the above package content, other products are not included.Note: Light shooting 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.