Due to the many types of electronic products and difference of the voltage of the power supply, therefore, a suitable voltage detection module and controller is in need. In general, the controller's analog interface to detect the input voltage is the largest 5V, which means that more than 5V of the voltage will not be detected. The voltage detection module can solve this problem. It can realize the detection of voltage higher than 5V. This module is based on the principle of resistance voltage divider, which can reduce the voltage of the red terminal interface to 5 times. Analog input voltage maximum value is 5V, then the voltage detection module input voltage is not higher than 5V * 5=25V (if you use the 3.3V system, the input voltage is not higher than 3.3V * 5=16.5V). Because the AVR chip is 10 bit AD, so the analog resolution of this module is 0.00489V (5V/1023), so the electric detection module detects the minimum input voltage is 0.00489V * 5=0.02445V. It plugs in sensor expansion board by 3P sensor connection line, not only can easily detect the current of the voltage power, monitoring the interactive media works or robot battery power supply, It can also be a voltage monitor as the voltage monitor IICLCD1602 LCD module displays the voltage degree.