Chronic Mechatronic Unveiling

Well, I've made a full fledged thermoelectric device that I plan on selling to advance the maker cause. This machine will be able to control the water content precisely while also hanging the buds from the stem so they don't deform. I'm using the weight lost from evaporation instead of humidity as an indicator of moisture content, which allows for any size harvest to be properly dried. (With humidity control the size of the machine has to match the harvest, or the humidity level will never reach saturation).

The chronic mechatronic is just part one of the process to get properly cured marijuana, I'm also about to put together another machine that takes bud from the CM, which is pretty much a ballpark moisture content, and puts it through a vacuum chamber to really dial in the moisture. Sadly, though, I won't be able to test it out till next spring.

I'll be putting together the CM this weekend and harvesting some tobacco (my weed seedlings got eaten by ants)

Putting it all together. There actually isn't very many parts for how much mileage I'm going to get out of this thing. But, as always I messed up a few things, not the least that something messed up with the two side panels so that they were dimensionally inaccurate, overshooting by atleast 5mm. But all the goals of the design are still getting met, i.e. no air gaps, and i don't have to recut anything.

A laser works great for cutting plywood like this.

burnpile said:

A laser works great for cutting plywood like this.

Click to expand...

I actually designed my own diode laser which i called the "PLAser" because its mostly 3d printed from PLA. You can't really find anyone selling a laser big enough to cut full sheets of 2x4 plywood, their either smaller or bigger (and cost allot).
I've been using 1/4 oak but this was my first time getting birch. Its about 2mm thinner but is perfect for something like this.

Everything is working now! I didn't think it would take so much effort and headbanging as it did. Basically you plug in a 12v source and it goes. I have it setup so that the TEC temperature can be set to the dew point and it only sips power (about 1.5amps). The plants are hanging from a load cell that tells me how much water has been driven off, and thus its moisture content. I think with tobacco I'm shooting for 12% of total weight, at 80 grams thats about 10 grams.
Chatgpt recommended the leaves be kept at 80% for about two weeks, then lowered gradually over a month. I'm just running a test batch right now, and i'm gonna just see how fast I can dry them.

The program code was a pain in the arse. I ran out of memory just when i finished the code and had to rewrite the display code using a simpler library. So its not as fancy as it could've been. The display basically has 3 screens, one screen shows the TEC status (on or off) and its temp, and then the humidity and temperature of the box, and also the weight is displayed. The next screen just toggles the relay for the TEC, and the last screen is to tare the load cell. Of course there are many more variables you could play with, like setting weight/humidity/dew point targets, but I'll be coming back to put in a touch screen at some point.

I'm pretty satisfied with my design for hanging the leaves. It uses the spring action to hold onto the stems as they dry. I used polypropylene filament to 3D print the spring part.

Finally finished with the drying box part of the Chronic Mechtronic. I put some finish on the wood, sealed up the door, and used some caulk to make sure no humidity is getting in. The scale is finally working reliably, loaded up with about 400 grams of tobacco leaves (max is about 1500). It works on 12v and pulls about 1.5 - 3 amps while cooling the TEC down to about 5 degrees below the dew point. I'm going to program it to turn off at about 80% humidity.
I've already got a handful of leaves that should be ready to shred up and go on to the next machine. This one is almost done with the design phase, I just have to make up the pcb. Its only function is to get the plant material down to the right moisture content using a humidity meter. The lid is motorized with small 28byj steppers and uses a small vacuum pump also. So the idea is that the lid closes, pulls a vacuum to get all the water from inside the buds to the outside, then because the seal isn't that good it will go back to ambient pressure. After some time you can read the humidity and that will inform you of the water content of the buds. If the buds are still really wet, then the lid opens to prevent any mold. I'm going to add a small fan to the lid too.

It has arrived! Finally!
This machine will take the buds that were dried to the ballpark range using the chronic mechtronic and get them to the perfect moisture level for canning. This is still pretty much a prototype, but its a working prototype. The only thing i was sweating about was getting the stepper motors to close the lid tight enough for a good seal. The torque probably isn't everything the motor can deliver, its drawing just .1 amps per stepper and i believe the max is .2amps. But the lid does open and close without binding. The seal from the lid to the baine marie is made from pourable silicon, and that little vacuum pump will get it down to about 4psi... but you only really need it to go to about 8 to bring out all the moisture from inside the buds.
The wiring inside is a mess because the stepper motor driver chip doesn't have an ideal pinout for a single sided pcb. Also, I wanted to try out using a mosfet to switch on the pump, but I got the wrong type. So I had to use a relay.

A little update on the other drying machine. The tobacco leaves started at 400 grams and are now at about 200. I'm just keeping the door open instead of using the TEC, because i'm offgrid and it draws about 2 amps. But once it gets closer to the final weight of 75 grams I will close the door (or when the humidity level starts going below 90%). I'm thinking i should integrate a exhaust fan into the design but I would have to use some kind of automatic vent. We shall see.

Now i just have to design some inserts for the baine marie and get a few tobacco leaves in there!

Squashed all the bugs out of these machines and now they are being useful bringing in my tobacco harvest before the artic blast later this weekend. The TEC can really suck the moisture out of these leaves!
I renamed them the BudCure Box and Cannaster. Right now the program is pretty simple, no fancy math just yet. The BudCure Box uses a fan to drive off most of the moisture, and the TEC to prolong the dry time. The TEC has its own temp sensor so I'm dialing in the condensation with a dewpoint calculation.
The cannaster is working pretty good too. I have a pretty simple program on it, you just hit start and it pulls a vacuum for about 5 minutes, and rests for about 30 minutes, and repeats. This is good for getting things to dry out. But I still have to write the program that will bring the buds to the perfect moisture content. And I already know how... just lift open the lid, read the humidity, close the lid and wait to see how much the RH increases. The whole purpose of this stage is to get the buds ready for canning/curing without having to burp them, so i think this will be sufficient.
I made a quick youtube video showcasing them.