Beverage Slot Machine

I built this BASIC Stamp driven slot machine as a way to hand out cold beverages during the annual Burning Man festival in the Nevada desert. Burning Man is a great place to find inspiration for projects because so many creative and resourceful people create interactive artwork specifically for the weeklong event. Since Nevada is widely known for its gambling, I figured I would add a bit of fun to the Burning Man philosophy of “gifting” by creating a slot machine that paid out in cold beers. It was a nice treat in the hot and dry desert.

Just like a regular slot machine, you pull the handle, the wheel spins, and if you are lucky enough to land on the right combination, your prize comes out at the bottom. Unlike traditional slot machines, this one only has one wheel divided up into 8 different combinations—four “losers,” three “winners,’ and one double winner. A counter continuously goes from 1 to 8 until the handle is pulled, which trips a switch that starts the wheel spinning. The wheel is a coffee can spun by a continuous servo controlled by the BASIC Stamp. I was planning on expanding the slot machine so it would have 3 servos controlling different wheels, but for the purposes of fun, 8 combinations seemed sufficient. Maybe in version 2.

I originally used another small continuous servo to turn the gate that dispenses the cans at the bottom of the machine. Unfortunately, the servo wasn’t stronger enough to hold back more than one can when in the rest position or to stop itself turning once it finished dispensing a can. I ended up using the highest torque servo I could find at my nearest RC hobby shop—a Hitec 805 with 224 ounce inch torque. I’m no mathematician, so I just used trial and error to figure out that I could stack up to 10 cans before the force pushed the servo passed its limits.

Since it wouldn’t be a true slot machine without an intoxicating and distracting assault on the senses, I add a QV306M4P Sound Playback Module to simulate the sounds of the wheel spinning and the big payout. It even taunts you with clips from movies if you lose. I unfortunately never got around to adding a dazzling display of lights to hypnotize you into playing; I left that to version 2. What I did add was a kind of failsafe device that I always believed “real” slot machines have. By adding a 418 MHz RF receiver to the BASIC Stamp, I was able to use a keychain transmitter to alter the outcome of the pull. Now, I really didn’t see this as cheating since I only programmed the remote to win. I really hate to see anybody lose, so if someone had a really bad streak, I was able to improve the 50-50 odds by 100%.

At Burning Man, it’s tradition to burn your art on the final Saturday of the event. I couldn’t bring myself to burn the slot machine, plus it didn’t seem very safe to burn these components. I have since used it for a charity carnival by adding a coin slot. When some drops in a coin, it activates a switch on the BASIC Stamp that than enables the person to pull the handle for a try at luck. Otherwise, if you pull the handle without paying, it yells at you for not paying.

Here is the source code: Download