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Remodel 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.


That sounds like a cool project. Unfortunately, I really cannot make any specific recommendations without specific questions about what you want to do.

  • Grant

We just want something that can take 6 inputs (the buttons for vending) and then outputs to a an LCD screen depending on which input was pressed. We will just bypass the coin machine and make it free to vend

You might try using an Arduino.

  • Grant

We actually did get one, we got an Arduino UNO and a TinkerKit LCD Module. My question now is this: I am going to wire the vending machine to bypass the coin machine and take that out. I am going to split off the wires coming from the buttons so that it will send to the Arduino as well, which input pins should I use, and how do i call those inputs, so that i can send it to the LCD. I want to to show “Please make a selection” all the time, then when a button is pressed, it will say something like “Vending Pepsi” or “Vending Mountain Dew” depending on which button is selected.

Here are the pictures as well.

It seems like most of your questions are about using the Arduino. You might try asking them on the Arduino forums. Additionally, you might try looking on the Arduino website for LCD screen libraries.

  • Grant

Please please please email me I am trying to remodel some vending machines and this is the first time I found somebody that may be able to help me. Msmirzaking. @ gmail.com