Muad.Dweeb said:

[custom inductor skulls I have made. Do not message, I don't sell these.]

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When I accidentally knocked my (old, naked) sterilizer off the table to its death a few days ago, the time had come.












This is more grow log than tek, but here are the parts if you are so inclined.

* Induction sterilizer (treedix and devmo have been fine)
* 12V 10A PSU (I used this one since it's small, but still too big to fit in the skull, so I like the wider silver metal ones better.)
* 5V Microcontroller (I had an arduino pro micro on hand, anything 5v and small will do)
* 12v to 5v buck converter (to run microcontroller)
* 5v relay
* VCNL4010 proximity sensor
* I2C Mini OLED screen (this one is 32x128)
* Emours Aquarium Skull
* Barrel jack fittings if you don't want to hard wire everything
* Extra coil wire and romex couplers if you want the coil driver coming out the back
* Dupont wire, hot glue, file/dremel, patience.

Total cost about $60 in parts.


My first goal was to have a PSU that would fit in the skull. Failing that, I wanted to 3D print an old book that it could sit on to hide the PSU. It was still too big so I just wired it separately outside the flow hood. While I was testing, it felt way better to use angled up.


Gather all the shit (Ignore the black 8266 board, I ditched that)



Wiring harness. Part one is Wall to PSU to barrel plug. Part two is barrel jack split into the induction side (14ga for all that) and microcont side (18ga). Duponts on the buck converter to the board. I left the sterilizer disconnected until the end.


Dupont all the things to the board. Sensor and screen share I2C on pins 2/3. Relay on 4. Pin locations can vary per board. Claude wrote 100% of the code for this, he'll tell you.

The sensor was very fussy about I2C hygene. Send stops and release the bus after writes before starting next read. Give 5ms between polls and 100-150ms per read cycle.

I built in a warmup/cooldown period so that you have to linger in front of the sensor for a beat before it comes on, and it can lose connectivity for a cycle or two before killing the coil. Build a timeout/duty cycle enforcement to prevent locking in the on state if the sensor freezes but the board is alive. Wire the relay to fail open if the board dies. Consider an easily accessible reset button (I did not).


Test fitting. My original plan was to put the sensor in the right eye, and the screen was just for temporary debugging while I was building. But the screen looked so cool in the eye that I punched the nosehole out and put the sensor there. It ended up being a more natural spot for seeing hand placement, so happy accident. Some bits of the eye socket had to be filed out to let the screen sit flush and centered. Fiberglass was inhaled.


Since I wanted the coil in the eye, and the driver in the back, I bridged the gap with the copper from my dead coil. I used these romex (house wiring) couplers to join. Sand the enamel off any non-tinned coil wire so it conducts. This works, but they get pretty warm and the whole thing smells like burning fiberglass it's kinda sus. Don't burn your house down. I am completely serious, that is on the table here.

Muad.Dweeb's tek covered the actual assembly of the induction unit, but I will add two important things that I learned but didn't photograph because it was late and I am terrible:
1. Instead of using the onboard jacks (melty) or soldering to the plate (near-impossible), use pliers to bend a tight J into the end of the coil arms. This can wrap around the two posts at the back of the plate (don't solder yet).
2. Lay a fat bead of hot glue across the plate under where the arms will go (stopping short of the J hook you'll solder), plop the arms down, and just gob that shit on, getting all over top and then around and under the board. This sticks much better, and absorbs all the mechanical stress much better, than solder would. It is also easy. With this done, you can solder the actual coil arms for connectivity, rather than structure. This is ugly but worth it.



Use a mix of hot glue, exasperation, and resentment to secure... all of it.






Teardrop text is the sensor reading















This is an honest-to-god fire hazard and would be much more manageable if it weren't in a fuckin aquarium decoration, but dang, it sure does look neat.