This is, by far, the most popular prop with the TOT'ers that I have. I'm sure it has nothing to do with the fact that it dispenses candy all night long! I actually have to tell the kids to move along and let other people have a turn. They move along and then right away rush back when I'm not looking. It's frustrating, but rewarding all at the same time.

THE STORY BEHIND THE PROP

I don't remember why, but I was searching the internet one day for a new halloween prop idea, and I stumbled across this video. It was all downhill from there. I had to have my own candy machine.

So, I studied the video for quite some time, and came to the conclusion that the candy machine didn't really "do" anything special. It simulated pulling candy from a bin, taking a paper ticket, and somehow magically the bags were filled. I also really liked the way the smoke stack went up and down. From the video, I couldn't really tell if the machine dispensed the candy bags or not.

Taking this as my roll model, I set out to try and reproduce it. This turned out to be a much bigger project than I originally intended. I didn't want it to be just a static prop that people looked at. I wanted it to actually dispense candy. Why? Well, so I could take my kid out trick or treating without someone needing to stay home to hand out our candy. Unfortunately, and fortunately, it didn't work out the way I originally intended.

When I starting thinking about what I wanted the prop to do, I quickly came to the conclusion that I wasn't going to be able to get it to function the way that I wanted it to on my very limited budget. Many drawings and ideas later, I came to the final design which is pictured and detailed below.

HOW IT WORKS

The operation of the candy machine is pretty straight forward. I have a hopper that stores all the candy. When the machine is activated, a small amount of candy is deposited onto the top conveyor belt. The top belt drives from right to left. Right before the candy reaches the end of the belt, the candy machine pauses for a couple seconds. It then starts up again and drops the candy onto the bottom belt, which carries the candy back to the right side of the machine, where it drops into a collectation tray which is covered with a piece of plexiglass.

Now that you have an overview, let me go into a little more detail. As you are looking at the front of the machine, the top right section is where the candy is stored. The hopper is basically in the shape of an upside down pyramid. The hopper is big enough to hold about 6 of the big mixed bags of candy available during the Halloween season. I don't put this many in because it tends to jam. I find that round candy, like gumballs, work best. Lollipops on the other hand, are a big mistake. That dang stick just glues up the works!

The candy is dispensed out the bottom of the hopper by way of a door connected to a pneumatic piston. When the machine is activated, the piston retracts which opens the door for about 1 second. This is just enough time for about 5 pieces of candy to drop out onto the belt. The belt and the drive mechanism is nothing more than I piece of canvas sewn into a long belt. I used spare plotter motors and line feed printer platens for the belt drive asseblies. From there the candy makes an out and back trip on the conveyor belts. When the candy is on the top belt, a set of lights illuminate the top belt. After a short pause, the candy drops to the lower belt for it's return trip, and a set of lights illuminate the bottom belt section.

The machine also blows 2 puffs of smoke. The first blast happens right after the machine is initiated and before the candy falls out of the hopper. The second blast happens after the candy drops into the collection tray. The machine is started by an illuminated push button which blinks randomly. After it is triggered, the light goes out to signify that it can't be pressed again untill the dispensing process is complete.

MAKING THE MACHINE COME TO LIFE

The whole thing is controlled using an EFX-TEK Prop-1 microcontroller. It is powered using an ATX computer power supply for the Prop-1 & belt motors, a 24VDC wall wart for the pneumatic solenoid valve and push button light, and straigt up 120 VAC for the lights. Since I didn't seem to have a common voltage with the parts I needed to use, I decided it was best to just "dead bug" connect everthing to relays of the appropriate voltage, and control the relays with the Prop-1

In the first couple pics, I had the candy machine on it's side. Turns out that last year I destroyed one of the wheels, which you can see in one of the pictures. Now, the candy machine has wheels capable of holding 330 pounds. Here is a rough schematic showing the general hookup of all the electronics.


The Candy Machine

New Photos to Clarify Some Key Parts

Halloween day, '07, turned out to be a bad year for the candy machine. For some reason, when I went to test it out, the pneumatics wouldn't fire properly. After a lot of troubleshooting, we ended up putting a sign on it saying "Out of Order". Needless to say, it had to be fixed for '08. After tinkering around with it for about an hour, I decided to just bite the bullet and rewire it from scratch. While I was at it, I was going to take a few extra pics to show the progress. Here are the pics that came from the rewire session.