How about a wheel with with a quarter or more cut out, on the 50th coin the wheel rotates the cutout allow the bottom of the box to drop emptying the box, as the wheel continues to rotate the solid part closes the box, wheel stops.
Lee
I like the idea of this... It sounds simple turning a wheel but I can't figure out how it would actually open and then latch the bottom. I get your idea of using a rotating cutout disk, but don't get how it will actually release and gather.EDIT - I understand now! However, the spinning mechanism would need to be mounted to the bottom of the box which wouldn't be ideal as mentioned in the last paragraph of this post. Guess you could use spur gears but that seems an added problem.
How about pivoting the base along its centre and driving it round slowly 180 deg.
Micro-switch situated to cut the motor once level, activating pulse just needs to be long enough to move the door/some sort of cam, off the switch. A bit like car wipers parking setup. 
I see another wiper motor finding a new home. 
I could actually use a stepper motor and simply spin the motor slowly 360!! I do very much like this..it is simple. I'm just wondering how much torque I'd need. I said 50 coins but actually I probably only do 35 or even 25 - not sure how much torque I'd need! Also I haven't got much room behind the whole thing for the motor but then you can get quite "short" stepper motors.
How about just a wheel, no box. The wheel is like a water wheel but only two "buckets". In other words it has just a single divider. It rotates 180 degrees to simultaneously empty the contents of one side and bring the other side up for filling with coins. When that side fills, it rotates another 180 degrees -- etc.
Actually it can be any shape, not just a wheel, as long as there are two of them, they face opposite directions, and the whole rotates 180 degrees to empty and bring the other side up for filling. Could even be a pair of boxes.
And actually, actually, (double actually) it doesn't even have to be two boxes. Could be only one box with an open top that rotates 360 degrees slowly and then stops upright again after having dumped the coins -- ready to receive more.
Problem with this method is the space needed on the front surface... Also, would it be working by balance? I think if I was going with a rotating container, I'd simply turn a box pivoted from the centre as suggested above.
Hi, Chris,
I'm not sure how much space you have, but I was thinking a horizontal "floor" to your box that is pivoted at one corner. Upon receipt of the 50th coin, you activate a motor to rotate your floor around this pivot point. (The "floor" will always remain... what's the term when something is parallel in two dimensions? Anyway, the floor does not tilt; the coins on it are pushed off by the lack of clearance between the floor and the side wall.)
The length of the activation pulse is relatively short, because you latch the motor using a cam and a microswitch. When the "floor" has turned through approx. 360°, the cam deactivates the microswitch and the motor stops, with your floor closed again. The advantage of this technique is that you don't have two separate "empty" and "reset" functions; there is only one "rotate floor" function.
BTW, we do something very similar with some of our paper cutter devices (used as components in other equipment). This ensures that the cutter blade rotates 360° and provides closed-loop feedback so that it stops in the same place every time.
Very very clever and simple idea and would be really effective...however, am I right in thinking that your moving mechanism would be either above or below the box?? Only I'd have to have the mechanism hidden at the side of the box...
Perhaps I need to make that clear... The box will be stuck to a surface on one of its sides. The coins fall in from the top. Whatever opens the box needs to be hidden behind the fixed side. I'm very sorry to have wasted time, that should have been clear in my original message. The idea of rotating the full box 360 is a good one since I can pivot the box from the fixed side. The only issue will be that the boxes full weight will be hanging from the mount of the box to the motor. Then again, 25-50 coins isn't such a great weight - 50 coins would be 325g
Really interesting ideas and has got me thinking! Any more feedback welcome.
