Liquid Level Sensing

There have been a number of posts on Twitter where people have used BBC micro:bits to measure water levels or soil moisture.

Normally these are done with resistive sensing which has a number of disadvantages such as corrosion of the sensor.

It seemed like this was a good opportunity to apply my capacitive sensing learning to a different application area.

If you want some background on how liquid level sensing works with capacitance then this video is very good:

To create the sensor, two strips of copper tape were stuck onto cardboard and placed in a freezer bag. It is important to get the two strips parallel and close as possible without touching. The cardboard is placed in a freezer bag to stop it getting wet. One of the copper strips is connected to ping GND and the other goes to pin 0

Here is a video of the initial experiment I did with this:

Using the following code:

This can also be used to measure the change in moisture in a plant pot. Although maybe the sensor needs to be redesigned a bit to fit into the ground better.

.. image:: plant_moisture.jpeg