Difference between revisions of "QTouch for Water Level Sensing"

Revision as of 12:07, 1 April 2015

1 Sensor: Continous Setup

Below you see some measurements using the QTouchADC capacitive sensing to monitor water level in a tube. During the measurement, I raise the level of the water in discret steps and then let it empty again. In the last part I physically touch my laptop or/and the wires between the arduino and the electrodes. The capacitive sensing seems to be ok to measure the water level from the outside, but of course there is major errors when you touch anything near the cables aswell. hmmmm... maybe shielded wires?

Having the electrode inside the tube gives me a much larger reading and less noise, but is not always wanted or possible in a real world setup.

Max measurement 120, steel electrode inside the tube

Non-contact electrodes are mounted on the outside of the tube on both side, one connected to the QTouch.sense channel the other to GND.

Max measurement 40, steel electrode taped outside the tube

Much more noise is present the laptop is plugged in and connected to the main power.

2 Sensor: Ring Setup at 2 different Levels

In this second setup, i tried to use 2 channels of the QTouch capactive sensing to measure the passing of the water level at specific positions on the tube. A steel wire was wrapped around the tupe as a ring, one on the very bottom is connected to GND, 3-4 cm above is a first ring and on the top part a second one.

Testing the passing of the water level to a ring electrode, non-plugged and plugged to main power

Code Examples on Github

https://github.com/dusjagr/QTouchADC/tree/master/examples