4-20mA Current Loop to Bluetooth Project.

Submitted by Brian on Wed, 10/23/2019 - 23:27


I'm new to this and not quite sure how to proceed so apologizes if I sound clunky.

I'm looking to connect an analogue moisture sensor running off a 4-20mA current loop to my android tablet via some sort of Bluetooth setup for monitoring.

I'd like to keep this project as simples possible as I don't know much about Bluetooth or app building.

I've looked around the internet at different circuit boards with Bluetooth from Arduino and a few others but they seem pretty advanced for my needs.

Does anyone have a simple, cheap, low power solution?

Also, once connected via blue tooth how do I display the meter readings on my tablet, do I have to get into coding or is there an app that can do this for me?






Hi Brain,

Since your sensors is current loop sensor you have to use a 4-20mA to 0-5V converter module. Because your sensors outputs 4-20mA while your controller like Arduino can only read voltage values from 0-5V. So first step buy an Arduino board like Arduino UNO and a converter module and interface your sensor with Arduino board. You can display the sensor values on Arduino serial monitor and check if the sensor values are read as expected.

After that you can buy a bluetooth module like HC-05 to send this sensor values to your mobile phone. There are many mobile applications available both for Android and Iphone to get values from Arduino via bluetooth. If you are looking for something with good UI you can check Blynk application. Hope this helps 

  Joined August 16, 2018      42
Thursday at 11:31 AM