For Halloween this year I thought it would be an interesting challenge to break out my LEGO Mindstorms EV3 set and build a robot for dispensing candy. These mini chocolate bars are pretty common where I live, so building a machine that would toss them at the kids seemed like a great idea!
It uses the EV3 Infrared sensor to detect when something is in front of the machine to trigger the delivery mechanism. The chocolates are stored in a gravity feed stack and are pushed out from the bottom using a simple piston arm. Once they are pushed out, they land on a platform that is rotated up to throw them.
I designed the feed system to be adjustable, so it can accommodate a range of these mini chocolate bars. Or pretty much anything that will fit and stack reasonably well.
The building instructions and program file for running it are here, and there are some construction notes below, along with the wiring info.
Instructions for wiring the motors and sensor are as follows.
Infrared Sensor: Port 1
Motor under the throwing platform: Port A
Motor under the feeding tower: Port B
This robot performs best with items that are rectangular and stack well. Some mini chocolates which are rounded on the top might not stack so well, so you might get mixed results with them. All the chocolates I showed in the video work quite well.
I had an absolute blast building and playing with this model, and eating all the chocolate that’s been lying around! I hope you have fun with it too.