Wanderful !

Hi !

Since few days, I’ve worked on the capacitive sensor controller but I still get a problem : when I read the capacitance of the sensor I use, I always read the same value, even if I put my hand on the pin sensor.

This CapSense controller converts the sensor capacitance into a count value, coded on 2 bytes. There are some debug registers and with them, I can read the count value. This one changes when I touch the pin with something but it changes a lot even if I just plug a simple wire on it, without touching it. Alexis has decided to take the board and try and understand this problem.

Thus, today, I didn’t work on the electrode part, but I have coded the sensor detection thread. Basically, when a player puts his thumb on the sensor, if he lets it enough time on the sensor, it means that a gesture spell will be done. During all the spell, the player has to let his thumb on the capacitive sensor. Once the spell finished, he just has to release his thumb of the sensor.

Moreover, I have corrected small bugs on the 3D model of the wand and we have printed it. For your enjoyment, here are some pictures of our wand (it’s the debug version, we’ll improve the design later 🙂 ).

See you !

Capacitive electrode and the wand


I’m currently dealing with the creation of a capacitive button. Since yesterday, I can talk with the capacitive sensor controller and thus, I can read the state of a specific sensor that I’ve configured as a button.

The problem is that as soon as I plug something on the sensor pin, I got the maximum value when I read the sensor output, in counts unit. I have tryed and tunned different configuration registers but I still got the same issue.

I was using a simple iron wire with a circular copper welded on one side, and the controller sensor pin on the other side. In general, the electrodes are directly over the PCB but in our case, we want the electrode to be remote from it. So, I think that the design of the electrode wasn’t good there is no ground close to it. I am presently reading the doc more carefully and I will try an other electrode design tomorrow, based of the information that I found on one of the datasheet.

Lastly, two wands have been printed but they have been a little deform, because of they’re position during the printing, implying difficulties to fit together the different parts. Mickael has adjusted some parts of the wand this evening to avoid this problem during the next printing of tomorrow.

You can see below 3 members of the Expelliarose team and the actual printed wand.


Good night !