Sugar Shack Monitor

Motivations

This goal of this project is to provide a simple service to allow the monitoring of the liquid levels of a container. Originally, this project was meant to be used in a sugar shack, a building where maple syrup is made. In this sugar shack, tree sap was pumped into a barrel, but there was no system in place to monitor the level of sap in the barrel to ensure it was not overflowing. This project was created to solve this problem.

Description

This repository contains two parts: Code for the ESP32 microcontroller, meant to be mounted near or on the barrel with a moisture sensor to detect the level of liquid in the barrel, and a web server to make interaction with the microcontroller easier, and handle sending alerts over SMS with a GSM module when the liquid level is too high. More detailed descriptions of what each part does can be found in the READMEs of the respective directories.

Usage

Required Parts

• ESP32 microcontroller
• Capacitive Soil Moisture Sensor
• Secondary computer on the same network as the ESP32 to run the web server
• (optional) GSM module with enabled SIM card to send SMS alerts

Required Software

• Flashing tool for ESP32. I used the ESP-IDF toolchain.
• Node.js for running the web server

Setup

1. Obtain the IP address of the web server computer
2. In the esp32/main/main.c file, change the DEFAULT_SSID, DEFAULT_PWD, and WS_ADDRESS to the desired values.
   • DEFAULT_SSID: The SSID (name) of the network the ESP32 will connect to
   • DEFAULT_PWD: The password of the network the ESP32 will connect to
   • WS_ADDRESS: The address of the websocket running on the web server computer. It should follow the format: ws://<IP_ADDRESS>:<PORT>. The default port is 8080, and should be used unless manually configured otherwise in the web server code. The IP_ADDRESS should be the IP address of the web server computer obtained in step 1.
3. in the web-server directory, run npm install to install the required packages
4. Run the web server code in the web-server directory using node app.js when inside the directory
5. Build the C source code and flash the ESP32 with the code in the esp32 directory.

The ESP32 should now connect to the network and begin running.

Adjusting the Sensitivity

The default sensitivity of the moisture sensor can be adjusted by changing the sensor_threshold value in the esp32/main/main.c file. This value is the threshold at which the ESP32 will send a message to the web server indicating that the liquid level is too high. The value should be between 0 and 4095, with 0 being the most sensitive and 4095 being the least sensitive. The value can also be changed while the program is running, by sending an HTTP POST request to the /set-threshold endpoint of the web server with the new value as a query parameter. The target URL should look like http://<IP_ADDRESS>:<PORT>/set-threshold?value=<NEW_VALUE>, where <IP_ADDRESS> is the IP address of the web server computer, <PORT> is the port the web server is running on (by default it is 8000, unless changed in /express-server/app.js), and <NEW_VALUE> is the new threshold value.