Voltage Tester Sensor Measurement Detection Module DC 0-25V Terminal Sensor Module for Arduino UNO Mega Robot Smart Car Geekstory (Pack of 10)

These are actually Divide By 5 Voltage Dividers consisting of 30K and 7.5K resistors. Accuracy is fair, about 1% and good enough for most applications. I am using them to scale down 50 watt solar panel voltages to within the 0-5 volt range of the Arduino Pro Mini's A/D inputs and they work good. Connections to the modules are a little strange but not a problem. For future projects though I will use individual 0.1% 30k and 7.5k resistors which I found recently at very good prices.

Works good. Slight varience in readings. Using with mcp3008 for reading voltage on raspberry pi. If you use this with raspberry pi make sure to use 3.3v to not burn out your gpio. And to stabalize readings pull multiple times and average reading. Adafruit mcp3008 tutorial works perfect.

works well

How do we power an esp8266 microprocessor with the battery while also checking the voltage with the voltage sensor? As soon as I unplug the USB cable, there is no power to the esp8266 anymore. I tried plugging a jumper wire onto the sensor's + pin and the other end to the 3V3 pin on the 8266, but that doesn't give it power. I also tried connecting the jumper wire to the 5V pin on the 8266, but still no power. If I connect the battery's wires directly to the 3V3 pin via a breadboard, my 8266 works fine. Anybody have any ideas? Is there any documentation for this Voltage Sensor board?

These little modules work just fine for measuring voltage. Although anyone could easily make their own, these are so cheap, why bother making your own

Each and every one of the lot works perfectly.

Works good once you measure the actual resistance and incorporate those numbers in the program.

These boards work very well. I am able to send the voltage from a 12V battery to the A0 pin. No problems.With the correct code on the ESP8266 I can get and display the voltage from my 12V battery.