Our original thought was to have a pair of active servo-operated button pushers. Once we realized the maneuverability available to us with the Mecanum drive, it was clear that a single passive button pusher would work just fine.
Our first try was a flat piece of wood mounted to a Tetrix beam on the front of the robot. It proved to be very difficult to position the robot well enough to actuate the button with this flat plate. Next, we tried a round pusher made by sawing in half one of the white balls from last year’s Res-Q game. This worked better, because the angle didn’t have to be perfect. But we were still frustrated because the button has a hard plastic rim and if the position was a bit off, the pusher would hit the rim and not operate the switch.
Wandering through our friendly neighborhood hardware store, we came across a soft (but not too soft) foam rubber toy football. We cut this ball in half and glued it to a plywood base that could be screwed to the Tetrix beam. Here is the half we didn’t use:
And here is our finished button pusher:
You can see slight signs of damage from practice sessions, but it still works very well. the horizontal position can be off by a couple of inches and still give us a successful push. Plus the soft foam minimizes the chance of damage to the beacon if we hit it a bit too hard.