I'm trying to measure the actuation force of buttons on the Playstation Vita, in preparation of building an external device that presses these buttons automatically. Specifically, I'm trying to measure the force required to push the buttons on the D-Pad on the left, and the action buttons on the right.
Googling "how to measure actuation force" will give you pages of results of mechanical keyboard enthusiast forums, and they often mention measuring the actuation force by stacking pennies / whatever coins you have until the key is depressed and the computer recognises the keypress. I can't do that normally here, since the buttons are really small (<1cm for the action buttons) and even the smallest coin my currency has cannot be stacked onto it without toppling over.
In an attempt to mitigate the problem, I made the following setup. It still uses coins as weights to push down the button, but I rested the coins on the ruler that in turn rests on another object of somewhat equal height/thickness to the game console, in this photo, the remote control seen in the background. I conducted the experiment by continuously adding coins with a game running on the console until it registers a keypress, and then summing up the weights of the coins.
However, the results are rather inconsistent and questionable. I repeated my experiments several times (by knocking down the coin tower and stacking it up again) as standard practice, and I got values ranging from 100g to 180g, which feels extremely high for buttons on a handheld game console, and that large spread seems to be telling me that my experimental technique is just plain wrong.
Some possible causes of inconsistencies from the setup:
- The coins are not the same - I'm stacking 5 different coins at once
- The coins are not stacked in the same order each time I redo the experiment
- The center of the coin tower is not aligned with the center of the button on the game console - I don't know how to do this without the coin tower making contact with the neighboring buttons or it toppling over
Some steps I have taken to possibly improve accuracy:
- The ruler used is a stiff metal ruler and does not bend significantly
- The ruler is kept horizontal
- The only points of contact of the ruler are the remote control seen in the background and a single button on the D-Pad.
TL;DR: How can I improve the accuracy of my setup, or other better ways to measure actuation force of such small buttons?
Update & Final Results I used the weighing scale method, and the results are 80g for the D-Pad and about 120g for the action buttons on the right. Thanks everyone!