STM32F401 ARM Arduino Mini System Development Board (Adruino Bootloader) tachometer it just uses the LED

it just uses the LED light of the Optocoupler IC to activate the relay

It also uses SnO2 material

making it easy for you to connect to various sensors

12V Relay board

Supporting multiple radio protocols

STM32F401 ARM Arduino Mini System Development Board (Adruino Bootloader) tachometer it just uses the LEDThe highly affordable STM32 Black Pill Development boards allow anyone to try out new ideas and to quickly create prototypes with STM32F103 core ARM Cortex M3. The function of STM32 Black Pill boards can easily be extended with a large number of modules and sensors. Software STM A comprehensive STM32 software HAL library together with various software examples are can use with the STM32 Black Pill Development boards, and seamlessly work with a wide