edit:

I've now cut, tested and fixed the design so it now works. The one in the pictures is made of 2mm perspex (from the scrap material pile). The door at the bottom is made from 5mm perspex to add strength, 2mm worked, but just seems to flimsy to have a 3 year old grabbing.

The crazing was due to the material being too cold when cutting and so overstressing with the laser heat. If you have the same problem, just put the pieces in the oven at 100-110C for 50 minutes, then leave to cool slowly, this removes the stress and stops it cracking when using solvent cement to glue it.

I should be uploading a better looking one, once I've tested it under use by an over excitable 3 year old.

https://youtu.be/g9Ga7IZQuYw

apologies for the poor camera skills. :~)

main:

This is a project I am currently building for a friend with a young child. They are trying to improve their behaviour, but wanted something a bit more fun than a sticker chart.

It has an A4 footprint, so should be cuttable in most laser cutters.

The coin slot first gets mounted on the wall. Every time the child is deserving of a reward they get a coin. They then get to watch it tumble down through the ramps when they put it in. At the end of the day (or even better the next morning) they get count up there score, before opening the door at the bottom and letting the coins back out, preferably into a bag!

This should be more effective than a sticker chart. The coin can be given immediately, even when they cant put it in the slot till later (eg good behaviour in the car). The visual effect of the coin bouncing down also acts as a reward in itself to many youngsters. Finally, they can save up points to 'buy' a reward. This helps reinforce the positive nature of the game, as well as building a sense of how money and saving works (do they want a trip to go to the park today, or save some more and get a toy they really want).

The design in semi parametric. It should scale reasonably well around it's current size, but might create some weird problems with extremes (particularly smaller sizes). So double check it is sane if you change much.

It is currently sized for 2mm thick perspex and takes 25 2 pence (UK) coins, but is easy to change both of these to whatever you have to hand (coins or tokens). The slope can also be changed to improve reliability at the cost of greater height.

I hopefully should have some pictures soon, once I've cut and tested it.