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jokerwanted 04-23-2013 03:36 AM

old Pepsi machine
My friend bought an old Pepsi machine for his new house. Right now it requires at least a nickel to vend, it uses an old dip switch coin mechanism, half of the "out of stock" lights don't work, the big Pepsi logo doesn't light up, the screen that displays the amount does not work, and the compressor makes a winning noise, but works fine otherwise.

We are going to school for computer and electronics engineering, so we are turning it into our final project. We plan to replace the current screen that doesn't work with a more modern screen, and we are going to remove the coin mechanism and wire it to vend free, and display the choice an the screen for this quarter. Next quarter we plan to to remove all the old buttons and mane then digital screens that we can program different pictures of drinks onto for vending.

So we have decent knowledge of electronics and I'm pretty good at C programming, there is a wiring diagram on the inside, and he thinks he knows how to fix the compressor whining. My question is this, do you have any recommendations for the circuit board we should use to wire it up to show what the selection is, and eventually be used to run the digital buttons. Maybe some suggestions on the screen to use and for the buttons later?

Thank you for your help, and I will post pics soon.

jokerwanted 04-23-2013 03:37 AM

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gottodo1 04-29-2013 07:43 AM

Don't you need to design the circuit board yourself? If not, a nice little atmel atmega 32 dev board is a good choice, simple easy nice EDK blah blah blah. I think you'll end up wanting a custom PCB though at the end of the day for what sounds like the 2nd half of your project so you can mux inputs and manage it all fairly simply, don't forget the temperature sensor and RTC. Molex makes a nice little LCD with everything integrated on it so you just need voltage and a few signal lines, pretty darn simple that mounts very simply and is quite good. Come up with a schematic and I'd be happy to review it for you.

Also do a system interconnect in Visio or A-cadd if you have it, system interconnects are the most important planning tool for any project. They identify the I/O, wire types, colors, basically what you see on that coke machine but detail it for your project. A cheap power source for all this is a small power supply from an old computer, you can usually get one almost free from the local IT group from an old scrap computer or a few $ from a thrift store. It even has a good connector for this type of project.

Should be a fun project. My Sr. Design was a remote controlled cooler that would dispense spirits, Profs & Frat Bros loved it. Unfortunately it died in a glorious accident, but it was great fun.

jokerwanted 04-29-2013 10:27 AM

Do you have any experience with the Arduino boards? We do not need to make the board ourselves, one person is taking a premise robot and modifying it. We heard several people suggest Arduino, do we got the uno with the tinker kit lcd. We are planning to have the wires that ran from the buttons to the coin machine go directly to the vending motors relay. And just split it off to the Arduino board as inputs, and then code it to display something like "please make a selection" when nothing is going on, then say "vending Pepsi" when a button is pushed.

gottodo1 04-30-2013 12:13 PM

The Arduino boards use the atmega 32 so that's exactly the type of thing I was suggesting, though I have no experience with the Arduino themselves the atmega 32 won't steer you wrong.

Just out of curiosity. Is this for your sophomore design project? If not I think it's too simple, but I suppose some schools let you get away with anything so they can get your money.

jokerwanted 05-01-2013 10:58 AM

This is for my micro controller class. Thank you for your help. I am going to ITT btw.

gottodo1 05-02-2013 10:13 AM

I knew a guy at Lockheed that went to ITT, pretty smart guy. So is this a sophomore class project?

jokerwanted 05-03-2013 11:33 AM

I guess sophomore, since this is my second year, I'm one quarter away from getting my associates.

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