No Touch Change Dispenser

This gadget was designed in response to the 2020 COVID-19 epidemic in the hope it might help reduce infection.

For small businesses that must use cash the cash itself is a potential fomite. This unit allows the cashier to give clean change, without touching it, to a customer who may accept it without touching anything else.

Suggested procedure for no touch cash handling:

Ask the customer to drop cash into a pot or tray kept for the purpose.
Count the money without touching it and calculate change.
Tell the customer to hold their hands beneath the outlet chute and dispense the change.
Remove any paper notes from the pot with tongs and put aside for cleaning later.
Tip the coins and any plastic notes into a bucket of soapy water which destroys COVID19. Within a few minutes you may remove and dry the coins to restock the dispenser.

Status

Fully functioning beta.

This has been tested with several hundred UK coins. I have very few Euro coins available so the Euro versions need more testing; I would very much appreciate a report from someone in the Eurozone. I have just a single US cent coin so the US version is untested, again a report would be valuable.

I apologise for supplying the project at such an early stage but, in the current circumstances, I believe that it is now ready for use and I am expecting to refine it in the light of reports from those who adopt it.

Printing

All prints so far have been made with PLA using a 0.4mm nozzle at 0.2mm layer height on a Prusa Mk3.

Files

Open the OpenSCAD source file.

The source is a somewhat inelegant OpenSCAD file which offers a selection of change sets, more can be added if needed.

Change Sets:

Sterling: All current UK coins. This set is too wide for many printers.
Short Sterling: All current UK coins except the £2. This fits on a 250mm print bed.
Euro: All current Euro coins - reduce the value of 'sideallowance' to 1.5 to fit a 250mm printbed.
Short Euro: All current Euro coins wthout the 1c & 2c - not used in some countries
Short USA: The most used US coins.

If you need a different currency you may edit the OpenSCAD file and insert the coin dimensions.

The OpenSCAD file offers other configurable parameters, the most useful is 'towerht' which sets the size of the coin stores. The current default is 100mm, it is not worth going much higher as stacks of more than 50 or so coins are too heavy and interfere with the mechanism.

Assembly

First check the prints for blobs and strings, remove them. Take care to check inside the coin tubes and use a long handled file to remove any rough patches.

Pre-assemble and check all is ok before gluing.

Use cheap contact adhesive - cyanoacrilate superglue has too short a handling time for this assembly.

Run a line of glue along the top of the base block between the mounting holes. Place the slider baseplate on top of the glue and gently wiggle it to spread the glue a little. Try to line up the holes ready for the tower mounting pins. DO NOT let the glue dry at this point, continue with...

Drop the sliders into place between the guides; each is fitted to just one slot.

Put a spot of glue onto each of the mounting pins on the coin tower, be sparing, excess glue will gum the workings.

Carefully align the tower pins with the holes in the slider baseplate and through them into the holes on the base block.

Gently push into place ensuring that all sliders are free to move then place a weight on top and leave to set.

When all is dry, loop a thin rubber band around the posts on either side and in front of the pushplate on each slider — use the thinnest bands you can find, these merely retract the slider after use.

Fix the dispenser in place with 4mm/#8 pan head or dome head screws. Site it with the chute over the edge of the counter so the customer can catch the coins in open hands without touching anything else. — If you don't want to spoil the surface of your counter attach it to a heavy board big enough to hinder an opportunist thief.

Now load in your coins and start giving change.