Measure fill-level of oil tank / water-cistern with Raspberry Pi and Ultrasonic Sensor HC-SR04

Measure fill-level with Raspberry Pi and Ultrasonic Sensor HC-SR04, log data into InfluxDB. Fill-level and historic trend data are displayed via a Grafana Dashboard, Grafana pulling the information from InfluxDB.

Hardware required

• Raspberry Pi (Pi Zero works as well)
• HC-SR-04 Ultrasonic Module
• Waterproof case for HC-SR-04
• Cable to connect HC-SR04 and RPi (4-wire)

Wiring

Following picture shows the circuit how to connect Pi with HC-SR04 ultrasonic sensor. In my environment the distance between Pi and HC-SR-04 is 6m, works without any problem.

You need the resistors (voltage divider) in order to drop the voltage going to the GPIO pins down to 3.3v from 5v.

Software components needed

• Python
• InfluxDB
• Grafana

Configuration

(1) Create Influx DB

• influx -precision rfc3339
• CREATE DATABASE Zisterne

(2) Adjust Parameters in the phyton code to your local config (InfluxDB) and tank (volume, height)

(3) Do a test-run the Phyton script

• run in a terminal to test, check the output.
• You should see log output of the distance measured

(4) Setup Grafana - InfluxDB Connection

(5) Setup Grafana Dashboard

• Use as example, you can modify based on your own needs

(6) Autostart of the program

• Add to /etc/rc.local following line to autostart the python program (run as pi, change path according to local environment)
• (sleep 60; sudo -H -u pi /usr/bin/python3 /home/pi/<path>/volume.py >> /home/pi/<path>/output.log) &