No Microcontroller In This Vending Machine, D’oh!

You might think that a microcontroller would be needed to handle a vending machine’s logic. For one thing, only the correct change should activate them and the wrong change should be returned.  If the correct change was detected then a button press should deliver the right food to the dispenser. But if you like puzzles then you might try to think of a way to do with without a microcontroller. After all, the whole circuit can be thought of as a few motors, a power source, and a collection of switches, including the right sized coin.

That’s the way [Little Puffin] approached this donut dispensing vending machine. What’s really fun is to watch the video below and wonder how the logic will all come together as you see each part being put in place. For example, it’s not until near the end that you see how the coin which is a part of the circuit is removed from the circuit for the next purchase (we won’t spoil it for you). Coins which are too small are promptly returned to the customer. To handle coins which are the right size but are too heavy, one enhancement could be to make them fall through a spring-moderated trap door and be returned as well. We’re not sure how to handle coins which are the right size but too light though.

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Donuts of ShmooCon

This weekend is ShmooCon, a hacker convention held in Washington DC. Brian Benchoff and I will be there, both of us for the first time. We’d love your input on what talks look the most interesting. Check out the schedule of speakers, then leave a comment below to let us know which talks you think we should cover.

It’s great hearing the big presentations, but I find a lot of times great hacks can be found in smaller venues, or just by walking around. Two examples from 2015 DEF CON: the best talk I sat in on had about 10 people spectating in the IoT village, and I had a great time trying to track down everyone who had an unofficial hardware badge. If you’re at ShmooCon and have something to show off, please find us (@szczys, @bbenchoff)!

On Saturday join us for a Hackaday meetup in the lobby of the Washington Hilton. ShmooCon is well-regarded for the quality of its “lobby-con”, what better place to gather? Look for the Hackaday crowd starting Saturday 1/16 at 8:45am. We’ll bring the donuts, and some swag like Hackaday Omnibus Vol. 02 and of course, some Jolly Wrencher stickers.

Solar cells from donuts and tea

It sounds unbelievable, but it is true. You can harvest most of what you need for a simple solar cell from powdered donuts and tea. Powdered donuts have nanoparticles of titanium dioxide which is a “high band gap semi conductor”.  This means that it can be used to make solar cells. The tea is simply used to dye the material so it can pick up the visible spectrum. The process is a bit too involved to be something you would just toss together in the field, but it’s cute nonetheless.