Clean the bottom of your chilling vessel, and the top of the Peltier. Then, cut a section of thermal tape to size, peel off it's protective film from one side, and stick it to the Peltier. Then, peel the other side and press the chilling vessel down onto it firmly for about twenty seconds for good adhesion.
This will greatly improve the thermal conductivity of the vessel!
Here you can see the frost building up on the exposed Peltier cooler as the liquid inside the vessel has be chilled from 22° C / 71.6° F down to 3.7° C / 38.7° F !
You can see from the photo of my workbench, that I've got a temporary setup in place while testing, but now it's time to neaten things up! You can build your own case/stand to elevate and enclose the electronics and make the button, switch and meter more accessible.
I designed a simple stand for this, which can be cut from wood or plastic on a CNC mill or laser cutter, or 3D printed. Download the file attached below to make your own!
Here are the same curves extruded into 3mm thick models for 3D printing.
In case you'd like to edit the file, here's a zip archive containing a .step file.
After measuring and designing the stand, I made a quick prototype cut from cardboard on a laser cutter.
This is very helpful in figuring out if things work before doing so from more expensive materials, or making a slow 3D print.
You can see here that I had mis-measured the panel meter size, so I adjusted that before continuing.
Once you've made your parts, go ahead and press fit them together. It may take a bit of trimming from a hobby knife to get an exact fit for 3D printed parts, but laser cut parts should fit together right off the machine. If you've laser cut the parts from acrylic, you can use some acrylic cement to fix them together.
Next, assemble the components to the stand. Start by removing the screws from the underside of the chiller assembly, and then screw them back in through the bottom of the stand to affix it. You may choose to remove the grill or leave it in place.
Push the panel mount temperature meter through the square hole, and then re-connect its two wire connectors.
Mount the PCB using four screws and two standoffs. Place each standoff on the back of the panel, then screw short screws in from the front to hold them in place.
Set the PCB over the standoffs, and screw them down with two more short screws.
You can optionally add extra heat sinks to the MOSFETs, although the cool well without them.
This may be helpful if you have very high ambient temperature, however, or run the Chilled Drinkibot for extended periods of time!
Switch & Button
Feed the switch and button through the holes at the top of the stand. You can then solder the button wires to the board, or connect with cold splices or interconnects if you chose to do that.
Slide the pump into it's place from the front, and then screw in a set of 2.5mm screws and nuts (or standoffs for convenience) to hold it in place.
Then, solder or connect it's wires to the board.
Lastly, feed the Peltier cooler and fan wiring in and connect them to their wiring on the PCB. Here, I did so using splice taps, but you can use removable interconnects or simply solder them together (be sure to protect with heat shrink tubing in this case.
With everything in place and connected to the board, you're ready to chill a beverage! Place the temperature probe into the chilling vessel, as well as the input pump tube, which you can cut to size. In the orientation shown here, the bottom tube is the input.
Then, pour an ounce or two of drink into the chilling vessel, and place the output tube into a drinking glass.
Plug the Trinket M0 into USB power, and then flip the 12V switch.
When you're ready, press the button on the front of the drink chiller, and watch the magic! After a few minutes, the drink will be cold, and the pump will transport it into your waiting glass. Enjoy!