RF Transceiver / LED Clip-on Drink Coaster Design Documentation
Konel Tech Blog #001
To recap from where we left off, so far we’ve created and used tambourine controlled LED unicorn horns, (As seen here) and light up ping pong paddles (youtube link) that make the table color change based on force of the hit. In the objective of seeing what else we can light up during events, especially items that showgoers would have, we decided to light up their drinks! So we picked up some Zima and Smirnoff to see what we could do with it. (glass beer bottles were not available at the nearest convenience store)
First I wanted to see how the bottle looked when illuminated from the bottom with a single LED. Of course I tried the light on my phone first, but it’s not quite accurate. I opened up Fusion 360 and designed a slightly oversized coaster/pedestal for the smirnoff bottle with a hole in the middle for the LED and enough hollow space below it to loosely place a battery, radio transceiver, and an arduino. I found models of the radio transceiver and arduino on GrabCAD (link) so I could keep them in the model to make sure the parts would fit in the model. The light worked pretty well especially with the cloudiness of Smirnoff. (it’s probably undiluted sugar)
This brought up some issues though. Should it be a coaster that you put your drink on? But then people can’t use it while they stand. Perhaps we could make mugs, but many people are drinking from bottles. Trying to make special bottles and then adding lights inside them sounds like some sort of healthcode violation….. Our next idea was to design an small item that would attach to the bottle. One idea was a rubber/silicone sleeve, but that could be problematic as well. It might have a chinese finger trap effect and not let go when you try to pull the bottle out of the sleeve.
Then i wondered if i could make something that would actually clip to the bottom of the bottle. The main measurements i took were largest diameter i could find on the bottom of the bottle, the smallest diameter after that and then the height from the bottom of the bottle up to the waist, or where the bottle starts to get smaller in diameter.I then took these measurements and started sketching in Fusion 360. I made the base about as small as it could go with the parts I had.
Next was to design the clipping mechanism. I want this device to feel and look light if possible so i decided to give it a bunch of thin fingers as opposed to a few huge clips. At first i made a cup like design and used a slightly smaller than bottle waist measurement to make sure there was force for the fingers to grab the bottle. The waist measurement was 54mm and i downsized it to 52mm. Then i made a negative piece to use boolean in order to remove the parts of the model i didn’t want.
One last feature to create before printing this object is a way to open and close the model to easily gain access to the electronic components inside. One of the better methods i’ve found it to create threaded objects. This is very easy in Fusion 360. You select the area where you would like to have threads and make not of what you’ve selected so you can have matching threads for the matching part. Fusion 360 will usually choose something that works pretty well. Because the goal is to 3D print this, the tolerances are not as small as they would be on a machined block of aluminum, so to compensate we can select a few surfaces of the threads and push them out about 0.1–0.2mm just to give it a little space for imperfections.
Next we will printing using our Afinia H800+. I am using a clear ABS plastic I found which turned out to to be much better than expected. First I printed the coaster as if it was sitting on the ground, but the fingers were too weak and were breaking a few minutes into its existence. The orientation of the first print had the fingers created by stacked layers, similar to piling up coins hoping for them to hold together while you push them around…. It didn’t work.
I immediately wanted to make some revisions to the design, but I want to avoid changing too many variables at once so I could solve each problem that arose. At the moment I decided to just print it again with the orientation flipped onto its side. This is so the plastic strands go vertically and continuously through the fingers of the coaster. This make the fingers much stronger, none of them have broken this round and they provide a lot of pressure and flexibility.
It works! It clips on to different bottles, doesn’t break, doesn’t fall off and it illuminates the bottle very well! This is a good proof of concept for the time being, but ideally I want it to look lighter and be more aesthetically appealing. Next I would like to try making it with fewer fingers, perhaps with a double 3 or 4 spoke style vaguely influenced by wheel designs.
