Improved Legs

Published on 2018-08-03 in Kubik M0.

One of the advantages of having the legs made out of PCB is that you can easily put things on them. Like, for example, switches that detect when the leg is touching the ground. I didn’t include that in the original design, because I was a bit in a hurry, but that’s not a problem, since I can make a separate set of legs easily.

It’s a bit problematic to find the right kind of switch for this. For one, it has to be edge-mounted, but more importantly, it has to require very little strength. Regular “tactswitch” buttons are useless for that, but if you look around carefully, you will find something that is labeled “card detection switch” — those switches are supposed to detect when something, such as an SD card, is inserted into a slot. As such, they are rather sensitive, requiring very little force to be pressed. And they are usually in the correct orientation.

One such switch is the Panasonic ESE22MH27 that I happen to have in my drawer. A quick search for images reveals this footprint image:

So I quickly made a PCB with the footprint, and added some prototyping area to the leg, for good measure:

One annoyance is that I need 4 of those, but OSHPark makes them in batches of 3, so I need to order 6. At least I will have some extras to break.