CandyBot

A no-touch, candy dispensing kiosk built for Trick-or-Treating during the COVID-19 pandemic.

Status: Functional

Video of Kiosk from front: https://youtu.be/tlIEr8h296Y

Video of Control Station usage: https://youtu.be/kWjWRuVtB2I

Kiosk consists of

• Raspberry Pi Zero W
  • Webserver for Kiosk and Control Station (NodeJS)
  • Signalling Server for WebRTC (NodeJS)
  • Stepper Controller (Pulsing GPIO pins)
  • RGB Lighting Controller (rpi-ws281x-nodejs)
  • Kiosk Signalling and Control (Socket.IO)
• Intel NUC
  • Runs display/graphics/webpage on Kiosk Screen
  • Encodes Audio/Video from Webcams/Microphone
    • 1 Webcam for seeing users
    • 1 Webcam looking into dispenser to monitor level and jamming
    • 1 Microphone (Webcam mics were low-quality)
• Custom Built Candy Dispenser using two NEMA 17 Steppers and a conveyor belt
  • My wife sewed a conveyor belt and then added hot-glue strips for better candy grippage
• 2x TB6600 Stepper Drivers on a 24V PSU
• RGB Lighting (2 x 43 LED Strips running in parallel)
  • Custom lighting modes
    • 'Flame' for normal operation, randomly fades each LED between red, orange, yellow
    • Selectable colors for interactivity with kids
    • 'Party', randomly changes the color of each LED to any color
• Logic Level Shifter
  • Changes 3.3V to 5V for RGB Lighting Strip

Control station

• A laptop/desktop which can receive audio/video streams from kiosk

Notes

• This system could be run over WiFi, but works best on ethernet.
• Firefox browser was used on the Kiosk and Control Station.
• I used candy which was consistent in size as differing sizes caused unreliable feeding and jamming.
• Due to limitations with WebRTC, in order to stream the desktop of the Kiosk display you must enable it by clicking a button on the display page. I accomplished this by using VNC to remote into the kiosk and starting the stream. Once enabled everything can be controlled from the control station.
• Kiosk/Control Station must use HTTPS due to WebRTC, certificates are included.

The code is a little rough around the edges, but the functionality is 100%. Some of the code is unused and some is not complete as I ran out of time at the end of the project. Getting WebRTC to stream audio/video was difficult for me to implement and is likely messier than it needs to be.