I have an idea to modify a fridge to accept payment for a drink (something like this).
I imagine it working like this: Each shelf has a fairly accurate weight sensor that can detect when a 12oz can has been removed. When a payment is received, the door unlocks and the purchaser will be able to grab a drink. Each shelf will have a different drink (i.e. Coors on Shelf 1, White Claws on Shelf 2, etc.) and each with their own cost. There also be some error detection and security to prevent people from trying to fool the machine.
Any ideas on what sensors I could use to detect the weight of a shelf?
It will work partially on the honor system but if you take more than one drink the machine will know. Say the drinks are priced as follows: Shelf1 ~$1, Shelf2 ~$1.50, Shelf3 ~$2. So when I pay the machine $1 it will expect 12oz to be removed from Shelf 1. If more weight (more drinks) are removed than an alarm will sound and you will be banned from future use of the machine.
The only way I see people stealing is if they buy 1 drink fairly but take a couple of others and swap out a dummy weight in their place. However, I'm not super concerned about this since I'm planning to use this at my house for parties/events and will probably notice when a drink goes missing.
You could make a dispensing system inside the fridge.
They sell racks and you could put a knob. Put in one dollar and the dollar knobs engage.
Once it delivers one beverage it disengages
one of these :
you could put a cage over the top
and an arm to stop the cans from rolling.
person opens the door
presses whatever selection they want, and one can is released.
it would need to have one motor per rack and some work on your part to make it work.
