ESP32 Based On/Off Boiler Controller

Sankar Cheppali | February 13, 2019 | ESP32, IoT, Javascript, nodejs | No Comments

How long it gonna take to build a simple end-to-end IoT application ? , lets find out. In next couple of blogs I will try to build a end to end IoT application. For demonstration purpose we will take a boiler automation use case. We will iterate our solutions to reach our final destination of fully automating the boiler setup

Environment requirements:

ESP32
Install latest version of arduino IDE and add ESP32 board using boards manger
Arduino libraries : PubSubClient,ArduinoJson (if you haven’t already installed it , you can install it from Sketch->Include library->Manage Libraries)
Install nodejs
Install mongodb
mqtt broker , if you don’t have one you can use eclipse Paho broker for experimentation (host: iot.eclipse.org , port : 1883, it is a free and open broker)
couple of LEDs,LM32 and breadboard to see the output

Current setup

Lets assume that there is a boiler in a industrial plant, something looks above. It uses electrical heaters, there is temperature meter and inlet/outlet. In the current scenario operator will take readings of the temperature periodically and switch on/off the heater based on the temperature

Now we would like to automate this system

ESP32 Circuit Setup

Hardware setup will be same for all the three iterations, Only the software will change. We need one LED (to indicate the heater status) and one LM35 to read the temperature. Connect LED to GPIO4 through a resistor and connect signal pin of LM35 to GPIO32 (Minimum voltage required by LM35 is about 4.4V, if you access to 5v supply provide 5v to LM35 vs pin)