Jackpot! How Hackers Made a Slot Machine That Mixes Drinks

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Brooklyn-based hackerspace NYC Resistor has built a drink-mixing slot machine inspired by Fear and Loathing in Las Vegas, and we’re itching to spin. Created as an entry into VIMBY and Scion’s Take on the Machine Challenge, a hardware hacking competition to give existing devices a totally new function, this winning mod beat out the entries of four other hackerspaces. With a $3000 supply budget and the rule that the hack must include a movie reference, NYC Resistor members set about shaping their solution to this open-ended challenge.

The members of NYC Resistor have made three previous generations of BarBots, so the decision to revisit the concept of a cocktail-making device was a quick one. Previous iterations, however, were built from scratch and not nearly as sophisticated; the designs were functional rather than handsome, and metered out random pours of liquor and mixers that were sometimes pretty nasty.

The idea to hack a slot machine for the next iteration of BarBot came to the team quickly, and a volley of movie tie-in ideas rejected Leaving Las Vegas ("voted down as being entirely too grim"), while Fear and Loathing in Las Vegas, the Hunter S. Thompson-based tripfest, was a natural choice.

They found a decommissioned, like-new Japanese slot machine on Craigslist that had been modified to meet New York State regulations by only taking tokens. The hackers decided early on that they wanted to maintain as much of its original functionality as possible, which meant they had to take it apart and learn how it worked.

The question of reading where the wheels stop with each spin--how the machine knows if you’ve got three cherries--required learning how to read the “stepline” system. The wheels are turned by stepper motors, which have several internal coils that magnetically turn the rotor. Drivers energize these coils with every turn, which emulates continuous motion. By soldering a wire to each of these coils and monitoring the number of times each one is energized and when each hits the zero position, they realized that they could count the wheels’ rotations and at what point it stopped.

BarBot's internals

From poking around the machine’s guts to the actual build-out, though, the idea and approach changed a number of times. They initially planned to assign ingredients to positions on the wheel, but near-undrinkable combinations convinced them to switch to a randomized reward system based on 30 or so preprogrammed cocktails stored in an sqlite database. As Hunter S. Thompson’s favorite drink was Wild Turkey, however, they mapped it to the big win.

Ingredients like vermouth, bitters, sour mix, and garnishes were kept on the side, and Resistor Max Henstell developed an Arduino-based LED screen to instruct players what they needed to add to their payout. This same display also cycles through quotes from the story, like “We can't stop here! This is bat country!!” and “As your attorney I advise you to to spin.” The video screen behind the sunglasses on the bottom image was also programmed with video clips, but it blew out a day before the project was finished.

For the beverage reservoirs, the team first tried using breast pumps to dispense pours. However, they couldn’t keep liquids and air from flowing back into these containers. Instead, team member Nick Vermeer developed a pressure bed system using 12 solenoid valves and modified food-safe jars from The Container Store.

Controlled by an internal netbook running a python script, the Arduino-controlled solenoids open in a timed sequence and dispense through a shared nozzle designed by Adam Mayer. Though these pressurized containers could have been dangerous, they were able to avoid booze explosions; the containers are secure with up to 30 pounds of pressure.

In the final version, they also added in a “cheat” that lets users request a specific cocktail to come up as the next selection, and gave the machine the ability to tweet the drinks it mixes through @luckyloathing. It took eight hackers three weeks and between thirty and fifty hours each to build this cocktail-slinging device, and their victory party must have been awesome.

[Photos: Copyright (c) 2011 Herbert Hoover/NYC Resistor; used with permission]

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