Button caps for Display-o-Tron 3000?

I’m thoroughly enjoying the Display-o-Tron 3000, which is a product I’ve been after ever since the RPi came out.

The DoT3K comes with a 5-way button; 4 directions plus press.

Could some kind folk suggest suitable button caps, please? It’s all very well without a cap on my Coupé case, but I intend to mount it under a regular Pibow Rainbow. Drilling a suitable hole in the top layer should be simple, but more challenging is accessing the button through the hole.

At the moment I’m considering taking a cross-section from the tube at the end of a biro, and then filling the tube with glue. Problem is, that sounds a bit hit-and-miss, with the miss probably permanently gluing a non-working cap to the button.

Two key areas I reckon we have to watch out for:

  1. The button downpress. The shaft of the button seems to be free-moving compared to the up/down/left/right directions which are on separate axes. The button cap must not stop any of these five movements.

  2. The button cap must not “fall out” of the hole drilled in the Pibow Rainbow top layer. So it needs some kind of flange so that the base of the cap is larger than the size of the hole we need to drill. Alternatively there is gluing, but I’d prefer not to glue my DoT3K.

Have you considered something like sugru to create your own rubbbery cap?

The sugru idea is interesting, although I’m not sure how you’d get it to the right shape? I had a laser-cut button cap on mine for a while, but removed it because it made it really hard to press “select” without accidentally pressing one of the directions instead. ( principle of leverage in action, I guess! ) So you’ll have to watch out for that, too!

Sugru is a nice idea! It should definitely be possible to mold a custom form that works…

Hi folks. I now have my preferred solution to this problem, and like all good solutions to problems, it involves Lego. Basically you can modify a 1x1x0.33 round Lego stud to act as a button cap, and then mount other Lego bits from that. There is a recess inside the 1x1x.033 round brick that fits the DoT3K’s joystick nub perfectly, but you have to cut away part of the brick to make it fit snugly.


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