[Josh] isn’t one to refuse a challenge, especially when robots are involved. The latest dare from friends and family? Build a beer robot that can bring beverages at everyone’s beck and call.
The build consists of two main parts: the refrigerated cooler and the butler part, which comes courtesy of a Roomba Discovery from a fellow roboticist. [Josh] is basing the design on double-walled and insulated restaurant coolers. He built the refrigerated beverage hold from two stainless steel trash cans, sized an inch or so apart in diameter, and filled the gap with expanding foam insulation. He then cut away several inches from the bottom of the liner can to make room for the cooling unit, reinstalled the drip tray, and made a [airflow-allowing platform] by drilling a bunch of holes in an antimicrobial plastic cutting board.
At first, he tried a Peltier unit from an electric Igloo cooler, but that doesn’t work as well as [Josh] hoped, so he’s redesigning the can to use a mini fridge compressor. This meant making custom evaporator and condenser coils from copper tubing to match the compressor’s load spec. Go through [Josh]’s build logs over on IO and you’ll get a free mini-course on expanding foam and refrigeration.
[Josh] is currently working on some different butler modes for this robot. These run the gamut from simply sitting nearby with cold beverages and opening with the wave of a hand to doing voice-triggered beverage butler-ing at everyone’s beck and call. We applaud his efforts thus far and will be following this one with great thirst interest to see how he handles navigation and voice control.
Most people would have been like ‘sh#t – peltier doesn’t really work’ – *bin* (I know I did). Building custom evaporators and condensers is next level. Super cool.
Now, this is a device that we all need to have and I hope he gets it working 100% very soon. Something like this is the key to mankind’s survival over the next 5,000 years. If this were coupled with a totally automated brewing and bottling device he would achieve the Holy Grail of mankind’s most important inventions.
Someone’s built AVGN’s Beer Droid
Peltier could work with double the insulation and putting it in the lid not the bottom, and pre-chilling the goods. Wires can flex reefer lines don’t. It would be quieter too.
Then there is that thing about not tipping a refrigeration unit on it’s side and not letting the oil drain to the bottom so as not to get sucked in to the piston before plugging it in. If it’s slow and gentle enough to not slosh a mixed drink it’d probably be safe. Still the motor unit inside is sprung and has the power wires to it. Both were not designed for a rough ride just quiet running whilst stationary. Good luck, good brew. It could look like R2D2, hah!
Disappointed he didn’t explain how to recover the refrigerant before pulling the compressor. In the US, it’s illegal to intentionally vent refrigerant in amounts greater than what is unavoidable while working on a refrigeration system. (At least it’s R134a so the bikini girls at the beach are still safe…)
Also, replace the filter any time the system is opened up for service. They’re very cheap and can prevent problems later on.
Most cheap 12VDC Peltier fridges/coolers will keep the cold but dont expect them to chill anything anytime soon. Typically underpowered two stage. There are better 12/24V DC units that arent really designed to run typical cigarette lighter 13.8VDC amps of 10-15A. More to the excess of 13.8VDC@ 40A for roughly same volume as cheap ones. More stages too. Then again I haven’t seen many with the heat side arranged below the cold side that werent intended as hot/cold reversible. Only one and it performed poorly for cooling. So what are the actual start amps of little compressor? Stall amps? I think a larger weight carrying capacity platform may be needed for compressor configuration. Not that it wouldnt be needed in peltier design. Trash can by itself probably exceeded roombas capacity. Big amp batteries plus inverter ,six pack of 12+oz drinks ,compressor and wonder if roomba can move at all. Docking to an AC source would be nice. Though troublesome probably best option IMO for this intent. Should mention that style compressor doesnt like to be tilted/jostled when in operation or so much as being moved while not running.
Roombas software is not likely to be helpful.
Interesting challenge. COOL to see what progresses. Thanks.
Finally, a robot I don’t have to fear during the soon-to-be-here rise of the machines.