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#3 - Dpad and buttons

A project log for Game-o-Tron Mini

A roughly credit card sized gaming handheld

david-boucherDavid Boucher 07/31/2017 at 20:090 Comments

I've been working on the dpad (direction pad) and buttons, but mainly the dpad.

There are a number of different ways to do this, the simplest being to have four separate buttons for up, down, left and right that are directly exposed to the front panel. This would be very easy to build but has a couple of disadvantages in that you need to take your thumb off one button and to press another and also pressing diagonals is awkward.

I've decided to go for a traditional dpad which allows the player to change direction without lifting their thumb. The configuration is four switches with rubber tops (these: https://thepihut.com/products/adafruit-soft-tactile-button-8mm-x-10) arranged for up, down, left and right and mounted on perfboard. Wedged in the space between the switches is a small 3D printed pyramid which is a pivot which stops left and right or up and down being pressed at the same time.

The dpad itself sits on top of this and is a plus shaped part. This had a rim at the base which traps it between the case and the buttons. The whole thing is screwed to the case front with cut down M2 screws. The two action buttons are a simplified version of this with one switch and a 3D printed cap. In the final version these will be colour coded.

Here are the parts:

And the assembled article:

This took a few tried to get everything the right size to work well. The dpad has to have enough movement so that each direction can be pressed down and close the switch but not so much that it rattles. Also the pyramid pivot has to be high enough to stop opposite directions being pressed together but if it's too tall the dpad can't move properly. The rubber topped switches work well here as they hold the dpad in place when not being pressed but allow it to tilt without closing the switch. These switches have to be pressed all the way down before they close.

The end result, whilst not as good as a professionally made dpad, works well and there is still scope for some fine tuning.

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