Wasserstand

Setup

1. Start the RPi and connect it to a network
2. Connect to the RPi over SSH and login
3. Install and configure Apache
4. Save index.html and check-water.py to the file locations
5. Make the Build
6. Execute nohup python check-water.py
7. Now you can open http://raspberrypi:8080/check-water to see the json output or http://raspberrypi/ to see the data visualised. If you want to see the data in your cli, you can execute curl raspberrypi:8080/check-water.

Build

What you need

• Raspberry Pi (I took a Raspberry Pi 4 Model B with 8Gb RAM)
• Resistor (Adapted to the required strength)
• Cable

How it's built

• Position of the sensors at the water tank:
  • The 5 cables which serve as sensors are attached to the water tank at regular intervals. The bottom cable (sensor1) is about 5 cm above the bottom of the water tank and the top cable (sensor5) is about 5 cm below the top edge of the water tank.
  • GND is at the same height as sensor1. If this isn't enough at your water tank, you can also add more GND cables to the water tank.
• Sensor connections to the Raspberry Pi:
  • The GND cable is connected to the GND port of the Raspberry Pi. In between is a Resistor whose strength is adapted to the required strength.
  • The 5 cables which serve as sensors are attached to GPIO ports of the Raspberry Pi. In my case, they are:
    • sensor1: GPIO 26
    • sensor2: GPIO 19
    • sensor3: GPIO 13
    • sensor4: GPIO 6
    • sensor5: GPIO 5
  • If you want to use different GPIO ports, you have to change them in check-water.py.

Important file locations

• index.html: /var/www/html
• check-water.py: /home/[user]