KQ Button Tester; nee Turbo Button
2017-11-16 22:19 - Making
I've never posted here about this device I made. I made it earlier this year, mostly as a joke. On the right, now mostly hidden by the fan, is a solenoid. It sits poised above a yellow arcade button, also mostly hidden by the fan. On the front of this view is the electronics and the controls are on the top, all glued to a huge 12 volt lead acid battery.
The original point was to be able to press that button with inhuman speed and accuracy. I managed to leverage that to contribute to some of my videos about Killer Queen. More recently I've been interested in figuring out how to pick good arcade hardware. The moving parts wear out and need replacing. Which ones to buy as replacements?
So I updated the device, not only can it push the button — normally the one in the real arcade, now (in the extra little bit of wood it's sitting on) a dedicated one — it can read its value. So it can be used to derive fine details about the performance of the button, when pressed. I want to do quite a bit with this. Here's one example:
ED 0 D 12272 U 12280 D 12284 U 12540 D 12832 U 12836 D 12844 EU 0 U 8364
That starts ED 0 for "event down zero". Then a bunch of lines D and U indicate the timing of "down" and "up" events observed, in microseconds since we started the "down" event. All real mechanical switches "bounce" a bit when activated (and deactivated, usually). In this case, the button first went down about 12 milliseconds after we started (it takes some time for the solenoid coil to charge up, then to physically move) and the switch contacts bounced apart and back together three times after that, taking just over half a millisecond to settle down into its final resting state. And in this case when it came back up, there were no bounces. In my limited experience so far, this looks like good performance for such switches.
This is just one bit of data but we can compare quality in the "bounciness" category pretty easily: how many bounces, and how long before the last one is done? I intend to follow this with a post containing a detailed summary of this, for several switches. I need to make a final call on exactly what I want to measure, and make sure my tool will do that if at all possible, so it will take a little time.
