VOLTAGE DIVIDER | Radical Tech Tutorials

#59 EXAMPLES OF SOME ANALOG SENSORS

Recently I have been working on a remote battery monitoring system. Hardware + the software side of things. During my research I played around with a few store bought sensors and some small homemade sensors. Surprisingly it’s quite easy building simple analog sensors with minimal waste and a reliable working order.

The biggest challenge has been fitting all the sensors on a small PCB and picking a MCU development board with minimal trade offs.

After some time I decided to go for the Wemos D1 Mini and an analog multiplexer to handle all the analog signals.

The three sensors I chose are Voltage divider ( homemade ), Current sensor ( store bought ) and a LDR ( homemade ).

In a future post I will show a relatively compact PCB with an MCU, wireless connection and voltage, current, watts, temp, light, onTime, WiFi signal plus send/receive data collection points.

Link to the ACS712 Current Sensor here.

ACS712 DATASHEET

GL5549 DATASHEET

#56 DIY VOLTAGE DIVIDER

In order to measure the voltage of a DC battery we will need a voltage divider sensor. I built an easy DIY voltage divider which works quite well. All we need are two resistors to measure the voltage in a certain way so our Arduino doesn’t fry.

After working out my requirements for a 12v 7Ah battery I came to the conclusion that I needed a 30k and a 7.5k resistor. This will allow me to measure DC voltage from 0.025v to 25v.

I only had to break the connection on the trace where the screw terminal was soldered to.

After creating a simple Arduino sketch I was able to output the data to the serial monitor. I had to add the correction factor of -0.150 to get an accurate reading after checking with two multimeters.