I've had this idea for a while, and believe it would be very useful.
The idea is a machine that holds a tambourine, and shakes it at an interval.
There could be a dial or buttons to increase or decrease the interval (speed).
This is sort of like a glorified metronome (thing that ticks to help keep the beat), but much more useful, because shaking a tambourine is a more useful musical sound.
The idea can be as simple as a little stand with a pole and a clamp that holds onto the tambourine,
and then a mechanism that maybe moves/slides the pole quickly up and down causing the tambourine to rattle.
Then this mechanism would repeat at intervals to keep the tambourine shaking to a beat.
I know Ben is not a musical guy, but this idea is rather simple but I believe fun and useful!
I'm a musician and this would be helpful and fun in many types of performances.
I've looked around a lot and not found anything similar to this on the market, or even someone that has built one.