Mistablik is an American high-school student who put his mind to finding alternate uses for the lockers that lined his school's hallways -- lockers that sit empty as students switch over to electronic textbooks -- and decided to build a tiny, secure, Arduino-based vending machine that would sell soda to his fellow students.
The build-log, on Instructables, is nicely detailed, though it skates over the issue of what he'll do when the inevitable ban on selling sugary drinks to students comes into effect in his school. As a bonus, he used the locker and a gimmicked tin to ask his girlfriend to the prom (dawwwww).
One of the key features the control panel had to have was theft protection. I didn't want others removing the control panel from the locker. The front of the locker has a lip where the door rests into. I cut two boards with the same thickness as this lip and cut slots in each board which would allow for a key driven arm to be pushed into when in use. Once locked, the control panel is "too big" to be pulled out. Then all I have to do to get the control panel out is turn the key and pull forward.
Once the control panel itself was finished, I encased everything into an acrylic box. The box would fit into the lunch box shelf inside the locker. I built supports to hold the battery in place, away from anything else. The back panel is held on by cabinet magnets so I can access the inside anytime. It includes a few holes for a power switch, which can be turned to "charge mode" connects two screw terminals directly to the battery. This makes charging much easier, as I don't have to open the machine up to charge it. Underneath the coin acceptor, I included a hole for a drawer which catches any coins put in. On the top of the box, I used the micro-switch from another arcade button as a cutoff switch for the battery. I didn't want the vending machine to be on while the locker door was closed, so as the locker door shuts, it hits the switch, turning the vending machine off.
The Soda Locker - Vending Machine [Mistablik/Instructables]
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