Water Level Measurement with Raspberry Pi

This project is meant to use a Raspberry Pi (model Zero W+ up to 4B) to help measure water level in a water tank placed on the roof of a house.

1. Set up the Raspberry Pi

1.1 Install Raspberry Pi OS and configure user, network and ssh access

• Flash Raspberry Pi OS Lite/Full (32-bit) in a microSD card.
• You can follow a headless configuration or use the advanced menu in the Raspberry Pi Imager tool to setup the user, network, and ssh.

1.2 Enable I2C communication in your Pi (serial sensors only)

If you are planning to use a serial sensor to read the level of your water tank, enable I2C on your Pi with the following command:

sudo raspi-config # then, enable I2C using the UI menu

1.3 Set up a static IP addres to your Pi

Edit the /etc/dhcpcd.conf file as shown in the official docs to have a static IP address.

1.4 Wire your sensor (discrete sensors only)

The developer's preferred wiring for a 14-bit resolution discrete sensor is detailed in the following picture:

Note: the wiring can be overriden by the user to fit their needs.

2. Integration with Alexa (optional)

3. Deployment

3.1 Prepare level_sensor.env file

Create a file under the name level_sensor.env and place the proper env vars as described below

# For discrete sensors (recommended)
WATER_SENSOR="discrete"
WATER_PINS="[14,15,18,23,24,25,8,7,12,16,20,21,26,19]" # override with your list (longer, shorter or with different GPIO pins)

# For serial sensors (to be deprecated)
WATER_SENSOR="serial"
WATER_MIN_VOLTAGE="2.0" # calibrate with your values
WATER_MAX_VOLTAGE="3.14" # calibrate with your values

# For gravity sensors (to be deprecated)
WATER_SENSOR="gravity"
WATER_MIN_REF="[-0.66, 13]" # calibrate with your values
WATER_MAX_REF="[5.6, 65]" # calibrate with your values

3.2 Prepare level_publisher.env file (optional, to work with Alexa)

Create a file under the name level_publisher.env and place the proper env vars as described below

LOCAL_SENSOR_ENDPOINT=http://localhost:8000

# All files below must be placed in a directory named "iot"
AWS_IOT_HOST="Your AWS IoT endpoint" 
AWS_IOT_TOPIC="Your AWS IoT topic"
AWS_IOT_CERT=your-certificate.pem.crt
AWS_IOT_KEY=your-private.pem.key
AWS_IOT_ROOT=YourAmazonRootCA1.pem

3.3 Install Python 3.9

From apt:

sudo apt update
sudo apt upgrade
sudo apt install software-properties-common
sudo apt update
sudo apt install python3.11-full python3-pip

3.4 Deploy into your Pi

sudo bash deploy.sh [reqs] # optional flag to install/upgrade Python dependencies

4. Check the water level of your water tank

With the IP address of your Pi, enter the following URL in your browser:

http://{IP_ADDRESS_OF_YOUR_PI}:8080

or, curl the following URL via CLI

curl http://{IP_ADDRESS_OF_YOUR_PI}:8080/cli