Hi everyone! I’d like to share the project I have been working on here. I got inspired to experiment with capacitive touch sensing through a project in my university. I found out about this technology through instructables and used the things I learned here and from other places on the internet to build my own touch-less controller, which I use to blend different RGB values to create interesting light colors.
For starters, when I started this project I knew next to nothing about either electronics nor capacitive touch sensing.
Some problems I ran in to early on were caused by misunderstanding what actually happens. So a short introduction from how I understand it:
A capacitive sensor uses multiple components, mainly:
A capacitor (in this project we use aluminium foil, but its also possible to use conductive fluids etc),
wires (ofcourse, its electronics)
and a resistor, anything under 10 MOhm is too small a resistance for more than direct touch.
the way it works is by measuring a difference in time between point A and point B. From the start pin it sends a signal to an endpin, the time it takes is measured with a timer. By decreasing the resistance value (by moving a capacitor (in this case your hand) closer to the capacitor of the sensor(the aluminium foil) this time shortens, the difference in time is what the sensor gives back as a value.
Due to the sensor being affected by capacitive surfaces the data can be wildly erratic due to interference. This can be solved for a large part by correctly insulating the capacitor and also by using a ground (I will show how later on) .”


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