Logo design by Aaron Liceaga


RePET is a functioning reverse vending machine prototype that recycles plastic bottles and dispenses a financial refund.



Alongside Sofía Sáenz I mainly worked in the mechanical area of the prototype, designing and building the structure and the mechanism to compact the PET bottles. We built a linear guide rail with a rack and pinion system powered by a 1/18 hp electrical motor and mounted it on a 60cm x 60cm 160cm structure made out of steel. I also helped with the machine’s interface – a 64×128 LCD and an arcade push button.


RePET is a mix of technologies and systems:

  • RFID tags or cards to identify the user and dispense money in the form of credit.
  • Ethernet shield to connect to compare the barcode input against a previously generated database.
  • Arduino to control the electronics.
  • A rack-pinion mechanical system to crush the bottles
  • A simple opening system to open/close the gate for recycling bin where the crushed bottles are stored.



A little about the process

As we have been abroad we could see a lack of an ‘environmental culture’ in Mexico. We all also had some interest in using technology for sustainability and making the mundane less of a pain. Furthermore, we came across The Fun Theory, a Volkswagen initiative with the thought that “something as simple as fun is the easiest way to change people’s behaviour for the better”. We then decided to build a machine that incentivizes people to recycle.

Thinking as entrepreneurs, we planned to get grocery stores involved with recycling. The idea behind the RFID cards is to sell the machine to stores and use their points card system. The financial refund would be tied to the store that has the recycling service. As a matter of fact, reverse vending machines have just arrived to Mexico City.



CourseBS Mechatronics Engineering curriculum

DatesJanuary - December 2011

Project TechnologiesArduino, Ethernet, RFID tags and reader, PS/2 barcode scanner, rack-pinion system, custom power supply