The Bar Monkey

*Patent Applied For*
Designed and Implemented by Steven Avery, Dustin Cooper, and Brad Greer
of Harvey Mudd College

The Bar Monkey, simply put, is a vending machine that serves mixed drinks. It houses 16 reservoirs which currently contain the following ingredients:

*Ingredients currently under consideration for replacement

Using these 16 ingredients, a total of 188 different drinks can be made, with the included ability to add ounce increments of each ingredient to customize (or create) a drink. The drink database is easy to update and nearly infinitely expandable.

Customers of legal age sign up for a user account, for which they are assigned a unique, 5-digit, hexadecimal PIN. The account is debit-based, with each drink charging the customer at cost for the drink they are purchasing, automatically deducting from their account balance.

All told, the project took about 3 months and $235 to complete. It is worth mentioning, however, that the LCD (the most expensive single component) was donated (approx. value: $100+), and various other components were otherwise acquired for free. The Bar Monkey was graciously funded by West Dorm HMC, even though we were overbudget by $85. Continual maintenance and occasional improvements are still always a concern.

Some Pictures:

Beta Testing
Here's the cabinet when it was just a few shelves holding empty 2-liter bottles. One pump is hooked up to the computer for the purpose of taking time-constant data.

Soldering I
Having collected the time-constant data, Steve and Brad dutifully solder half-inch jumpers to each of the 4 leads on each of the 16 relays. Neither of us knows, to this day, why we did this outside.

Soldering II
Closeup of the meticulous but tedious jumper-soldering process.

Bartop Under Construction
The unfinished bartop, with various tools, containers, and other helpful things strewn across it in the midst of hard work.

The Monkey's Central Nervous System
The finished relay board, connected to the computer via parallel ports. The computer is running the Bar Monkey program, which displays the drink code prompt on the LCD.

LCD and Keypad Closeup
The above-mentioned drink prompt, but closer.

Behind the Scenes of the Relay Board
It looks really nice and neat on top, but the relay board was quite possibly the most difficult part of the entire project. What you see here are 16 relays, 16 diodes, 16 resistors, 16 transistors, and approximately 70 small segments of wire (not counting the 64 jumpers).

Inside the Finished Product I (shown above)
Pretty self-explanatory. The pumps and their respective reservoirs in place, the computer and relay board safely tucked on a shelf, the LCD behind a half-inch of acrylic, and all the tubes pulled through the PVC dispenser neck.

Inside the Finished Product II
Same as above, but from a different angle.

Electronics Closeup
The LCD, with extension cable to the keypad and serial cable to the computer, is at the top right. The bottom of the computer is unimpressive, though dominant in the frame, and the relay board is seen off to the side.

Outside the Finished Product
Here we see the Bar Monkey as customers see it, complete with Dustin's excellent stencil design and the nozzle, which is removable for cleaning.

The Finished Bartop
The top of the Bar Monkey, covered in rugged black plastic with a viewing window for the LCD.

Finished LCD and Keypad Closeup
It still looks pretty much the way it did when it was unfinished, only now it isn't just laying on the floor.

Drink Confirmation
The true beginning of the customer's experience with the Bar Monkey.

Technical Specs: