by emily_littlebits

Published on March 16, 2015

The drinkerBot is a robotic drink mixer that serves made-to-order drinks. 

It works with a web app that allows you to specify whether you want a specialty cocktail, a DIY concoction, or a surprise mixture. Once you’ve chosen your drink, the web app tells the cloudBit what drink to make. The cloudBit’s signal is then passed through a littleBits Arduino module and some logic modules to determine which liquid dispensing mechanisms to activate. The drinkerBot also has a conveyor belt for your cup to travel on during its journey from empty to delicious.

This project was created for the littleBits 2014 holiday party and designed by a cross-disciplinary team of engineers, product designers, graphic designers, ux ninjas, media masters, and cloud aficionados in the span of about a week. We wanted the drinkerBot to be fun, engaging, push the boundaries of the littleBits platform, and actually work! The first iteration, which you see in the video, is made up of parts and pieces from around the office and a few specialty purchases. This is an ongoing project that we plan to iterate on to make more robust and reliable for future drink mixing adventures, so stay tuned for updates! The instructions below are more general vs. step-by-step at this time. As we perfect the design, we will update these as well. We look forward to your comments and suggestions for improvement!

Credits: Alin Cosmanescu, Geof Lipman, Ed Bear, Stephen Conover, Colin Vernon, Shem Rajoon, Eva Neesemann, Rochelle (Rolo) Lo, MK Luff

How To Make It


The drinkerBot is made up of many moving parts!

1. Custom web app that talks to the cloudBit through the cloudBIt API

2. Arduino module that reads the signal from the cloudBit and distributes it through a series of logic modules to control 12 servos.

3. System for dispensing liquid that is activated by the servos.

4. Conveyor belt powered by 8 DC motors and controlled by a second Arduino that moves the cup along to the filling station.

5. Mobile kitchen cart so the drinkerBot can travel around the office easily.

6. A few choice specialty concoctions!

Keep reading to learn more.


The web app is designed to allow you to choose any of these 4 drinks:
Salty Dog - grapefruit juice, lime juice, gin
Moscow Mule - ginger beer, lime juice, vodka
Greyhound - grapefruit juice, vodka
Gin Ricky - Soda, lime juice, gin

The “surprise me” button doles out a random concoction, and the “mix your own” button allows you to choose what liquids to add and how much. Here you can make non-alcoholic beverages too! Also, within each of the premixed selections, you have the option to edit and customize the ingredients. [there was some serious thinking about which 6 liquids to include, and the combinations turned out quite nice. We did learn however [after the fact] that carbonated beverages do not work very well with our liquid dispenser. We will take that into account for next time!


When someone chooses a drink, the information from the web app is sent to the cloudBit as a series of voltages over time. The Arduino is programmed to read these voltage sequences and determine which servos to activate, and for how long. Check out the Arduino sketches we used in the “Additional Files” section of this page. We bought an off-the-shelf 6 bottle liquor dispenser from barsupplies.com. This liquor dispenser is spring loaded, and to get liquid to flow, you just place a cup underneath a spigot and press upwards. Because we wanted this mechanism to be automated, our challenge was to see if we could recreate the motion of pressing upwards with servo motors. We ended up using two servo motors per dispenser. When they receive a signal, the two servo motors turn in unison, pulling on a wire that is tied around the base of the dispenser, pulling it upward. We also ended up hacking some of the small parts inside the dispenser itself as it proved too much force for the servos to move at first. We removed a spring and a plastic ring, which made the dispenser much easier to pull up on. We also extra weights to the dispenser base [heavy nuts] so that gravity would pull it down and seal the liquid inside once the servos released.


The conveyor belt is made using 3 fence rollers and a sanding belt. Yes, we were crafty here :). The sanding belt is wrapped around two fence rollers that are bolted down an aluminum channel and tensioned. We placed a third roller underneath the center of the belt as well to help it move more smoothly. At the ends of each roller is a mounting board with 4 DC motors + Pololu wheels. The moutning boards are held in place by L-brackets at the ends of the aluminum channel. In order to make sure that the right amount of rolling force was applied to the outside of the sanding belt, we placed shims between the L-brackets and mounting boards for easy adjustability.

The interaction with the conveyor belt is as follows.
1. Press a littleBits button to start the conveyor belt
2. A cup traveling along the conveyor belt stops when it passes between an IR LED and a light sensor. This is where the drink gets poured. To retrieve your drink, simply press the button again and the conveyor belt runs for a programmed amount of time, stopping the cup before it falls off the edge.
3. Because the motors draw a lot of power, they needed their own power source, so here we did something tricky. Because we wanted all the circuitry to work together seamlessly, we used an IR transmitter and an AC Switch to power the conveyor belt on and off.


Once we had all the moving parts worked out, it was time to build the structure. First, we made it mobile by placing everything atop a kitchen cart. We bolted the conveyor belt down and build a structure out of wood panels and studs to hold the liquor dispenser and house the funnel system and light sensor circuit. There is a small funnel that sits under each liquid dispenser that pipes liquid through silicon tubing to a larger funnel that hovers over the cup. Because this project was making its debut at the holiday party, we wanted to dress it up a bit too. We added some laser cut acrylic to the top and to the side panels with custom cutouts.


Things we learned:

1. Carbonated beverages don’t work with this liquid dispensing method.
2. Wood in not the best material for a liquid based project :)
3. We loved working together to make something epic! Until next time...

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