Notice: The new tracking number for China Post Ordinary Small Packet Plus only can track it have been ship out of China, not more Tracking information ,even it arrived or not . Please do not freeloaders,if you can not accept without more tracking information . Please choose China Post Air Mail if you want a full tracking info. Tracking info of China Post Ordinary Small Packet Plus can be check here : www.17track.net/en Module Description: This module is based on a resistive divider design principles, can reduce the voltage of the input terminal connection five times, analog input voltage up to 5V, then the input voltage of the voltage detection module can not be greater than 5V × 5 = 25V (3.3V if used system, the input voltage does not exceed 3.3Vx5 = 16.5V). Because AVR chips used in 10 AD, so the simulation resolution of this module is 0.00489V (5V / 1023), so the voltage detection module detects minimum input voltage is 0.00489V × 5 = 0.02445V. Parameters: Input voltage range: DC0-25V Voltage detection range: DC0.02445V-25V Voltage analog resolutions: 0.00489V DC Input: positive terminal connected to VCC, GND negative pole Output interface: “+” then 5 / 3.3V, “-” then GND, “s” then the AD pin Reference Code: #include <Wire.h> int val11; int val2; void setup () { pinMode (LED1, OUTPUT); Serial.begin (9600); Serial.println (“Emartee.Com”); Serial.println (“Voltage:”); Serial.print (“V”); } void loop () { float temp; val11 = analogRead (1); temp = val11 / 4.092; val11 = (int) temp; // val2 = ((val11% 100) / 10); Serial.println (val2); delay (1000); } Free shipping is ship by China Post .15-40days to arrived.Pls wait in patient. In urgent pls choose DHL ,Fedex and so on. Pls don’t leave your Negative feedback before contact us . i believe we can solve the problem together! Your Positive feedback is our business life. It is our blood!!!