World’s Largest Vending Machine

As the Lead at North Street Labs, I was faced with the daunting task of creating the largest vending machine in the world for Doritos at South by Southwest. We had a total build time of 3 weeks, including sourcing of parts. We had to make a gigantic 800 full size chip bag vending machine controlled by both Twitter and Ipad. The completed machine would tower a monstrous 6 stories tall, and the “chip panel” was a considerable portion of it.

Our first obstacle was getting a reliable release mechanism for the chips. We had to keep costs down and the mechanics simple for fast reproduction. We purchased bulk metal strips from the local hardware with pre-stamped holes, and we bent them so they lined up.
We planned to use a pin through the metal holes to retain the chips in place.We discovered that the bags’ standard mounting tabs were not robust enough to hold up in the wind without tearing, so we applied the “O” shaped paper protectors everyone used to use in grade-school binders. Some people call them “paper A-holes” for short. The mechanical drop mechanism used solenoids that retracted when energized, pulling the pin to release the bag. We needed so many solenoids that we completely cleared out Sparkfun electronics, and the few remaining missing ones came from Adafruit.

   

We formed a matrix of solenoid release pegs, designating rows and columns like a game of battleship. All of the bags came back to a central “brain” hub that controlled the releasing. Our electronic controller had to do a number of things. First, it had to connect to the internet and use Twitter API. Second, it had to accept IPAD commands through local wifi. We used a Raspberry Pi for both of these
tasks. From there, the Pi communicated with an array of Arduino Megas with enough digital I/Os to account for the whole machine. The Arduinos then branched off to the array of relay boards that energized the solenoids to pull the pins on all of the individual bags.

  

We had to work in collaboration with a large scale production company that built stages for major entertainment venues. We mounted our panels via U-bolts to their aluminum truss, and they lifted it into place. From there, it was our job to roll our power plugs and break them out to the solenoids on our control brain.

 

We knew the build would be difficult. Count to 800 in your head. Not only is that annoying, it’s tremendously time consuming. We had to do every single minor task this many times, and when we forgot something like missing a zip-tie, it was 800 mistakes. The scale of this project was massive, but we had a blast. It was incredibly rewarding to see it come to life.

 

Project Details

6 Arduino Megas
1 Raspberry Pi
200 Lines of code
2 Miles of Wire
800 Solenoids
126 Relays
18 Sheets of Plywood
4800 Bags of Doritos
2 Deep Cycle Lead Acid batteries
2 Buckets of Tears and Sweat
3000 Miles of Driving
0 Sleep