Pi Cap troubleshooting
Find out how to fix your Pi Cap with the Pi Cap Troubleshooting Guide
Step 1 Unable to install
All the instructions on how to set up the Pi Cap are covered in our set-up tutorial. But sometimes something can go wrong. The Pi Cap is a Raspberry Pi add-on and the Raspberry Pi community is large! So if you get stuck somewhere, there should be an error message. Copy-paste the error message into Google and see if someone had a similar problem and found a solution.
Step 2 Unable to trigger the sensors
The sensors might not respond or trigger an output erroneously for a couple of reasons. First, make sure that you are not touching the sensors when you run the code for the Pi Cap and that the Pi Cap isn’t placed on a conductive surface.
If your sensors aren’t responding, then we always recommend using the Grapher first, it helps you visualise the sensors. Work yourself up from testing the electrodes directly on the Pi Cap to one large sensor after another.
If you are attaching anything to the capacitive sensors of the Pi Cap, make sure to cancel the code you are running first. When the code first runs, it spends a few seconds finding a background capacitance level against which to detect touches, any time you connect something new to the Pi C you need to let it readjust so that each electrode can do the necessary calibration.
Make sure that any connections to the sensors is stable and constant, so for example with alligator clips, make sure that they are secured to the surface and are not overlapping each other. In your design, there shouldn’t be any displacement of the sensors. Overlapping clips can cause interference and noise, so stabilising them helps.
If you are painting long lines with Electric Paint as an interface, you need to be careful. Electric Paint can have a high resistance over a long distance, which means that the signal might get lost at such a long range. You can then either paint shorter lines with Electric Paint or change the threshold values. You can change the threshold values with the code in order to detect your target, you can even have a variation in the thresholds for each electrode. Also, make sure the Electric Paint hasn’t cracked anywhere, if it has, just apply another layer of Electric Paint.
Also, like with wires, make sure that the Electric Paint connected one electrode isn’t touching the paint of another.
If you are using long cables to create sensors, make sure to use shielded cable, otherwise, the non-shielded cable will pick up noise.
Sometimes, there can be interference with the sensors due to background noise or because a ground reference is missing. This is especially true for when using the Raspberry Pi with a battery or a power bank. One quick way to eliminate this noise is by grounding the Pi Cap and connecting the GND connection of the Pi Cap to ground.
If you get stuck and can’t figure your problem out, let us know at firstname.lastname@example.org.