High-Tech Alms Collection With The ESP32

In an ideal world, shop space, tools, and components would be free. But until we get to that Star Trek utopia, hackerspaces will have to rely on donations from the community to help stay afloat. While asking for money, at least you can have some fun with it if you design and build an Internet-connected donation box.

Or at least that’s how [Goran Mahovlic] handled it for the Radiona hackerspace in Zagreb, Croatia. Not content with just cutting a slit in the top of a shoe box, he came up with a physical donation system that’s not only more informative for those donating, but more organized for those collecting the funds.

The key is a arcade-style programmable coin acceptor from SparkFun. When connected to a microcontroller, this allows the box to keep a running tally on how much money has been inserted. With the use of a RFM96 LoRa module, it can even report on the current haul while remaining mobile; perfect for when the hackerspace has events outside of their home base.

But counting quarters is hardly a task befitting a powerful microcontroller like the ESP32. So [Goran] gave the chip something to do in its spare time by adding a couple of buttons and an LCD. This allows the user to scroll through a list of various projects that are looking for donations, and decide which one they want to financially support. When the donation box counts how much money has been inserted, it records which project its been earmarked for.

Of course, if you’d rather the free market do its thing, we’ve seen this same coin acceptor used to build a locker-sized vending machine. Or if you’re feeling crafty, you could always try your hand at building one with cardboard.

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Hacking Coin Collection

Coin Acceptor

Devices that collect coins for payment typically use standardized coin acceptors like the one shown here. These devices use a protocol called ccTalk to let the system know what coins were inserted. [Balda] has built tools for implementing the ccTalk protocol to let you play around with the devices. He also gave a talk at DEF CON (PDF) about the protocol.

[Balda] got started with ccTalk because he wanted to add a coin acceptor to a MAME cabinet, and had a coin acceptor. His latest project converts ccTalk to standard keyboard keystrokes using a Teensy. The MAME cabinet can then interpret these and add to the player’s credits.

There’s two interesting sides to this project. By providing tools to work with ccTalk, it’s much easier to take a used coin acceptor off eBay and integrate it into your own projects. On the other hand, these acceptors are used everywhere, and the tools could allow you to spoof coins, or even change settings on the acceptor.