Simple ceramic vape circuit.

A friend brought me a crippled vape, and I wasn't able to figure out what failed with a multimeter. The fuse and the ceramic heating element were still good, and the problem seemed to be somewhere in the super chippy logic side of the board.

Now I am starting a new circuit for it. If I can use the same heating element and housing, she can still use the same wicked whip that came with it. How do I determine the wattage of the heating element? What safety features should I add, and is what I am about to do going to work?

I have a super accurate infrared thermometer. I was planning on just picking up a dimmer switch, dialing it all the way down, and turning it up until I got the element to 190 C. Then I could just check the resistance of the dimmer, get a resistor rated for whatever the wattage is at that resistance and wire that in before a pot. Then do it inline with the wired in resistor checking for 160 C and wire in that pot with a resister equal to what the dimmer read that time.

Would that work to have a knob that only gave you temperatures you could possibly want your vaporizer to be at?

No, wait...

If I picked up a 120+ watt dimmer switch somewhere and wired the heating element from the vape in, I could use a infrared thermometer and adjust it to the minimum temperature. Then I could take it out, measure the resistance on it, and put resistor/resistors equal to that just after the on switch and fuse on the positive side. Then, I could wire the dimmer back in parallel and find max temp). Then a pot with that resistance at maximum would switch between that minimum and maximum temperature, right?

My other idea was crossfading between the maximum and minimum resistance (found by themselves, not using the parallel measurements from earlier).



From the design of the thing, it doesn't seem hard to make one radially actuated. I didn't find a radial cross fade switch. Probably calling it the wrong thing? And the wattage rating on that one is probably tiny.

You should contact @Hippie Dickie, IIRC he chose digital PWM versus analog for a good reason and recently mentionned something in another thread... maybe he will chime in?

sorry ... i don't have anything to add to the discussion ... don't know that vape or how it's rigged up ... i went a different way.

What was the reasoning of going digital, and what is the cost difference?

I will post pics for context soonish. It will be a little while before I am back where it is.

SaltwaterReefer said:

What was the reasoning of going digital ...

Click to expand...

i wanted computer temperature control - i.e. read the heater temperature with a thermocouple and adjust the current flow to the heater coil to maintain a preset temperature throughout a session. all my vape designs up to this point always dropped temp about 50F during a hit - the heater wasn't powerful enough to instantly compensate for the drop in temp from airflow - and this was the way to solve that problem, along with two A123Systems batteries that can deliver 70 amps of current.

digital let's me select any temperature up to 500F - the safety cutoff.

the buttons are rated for a million clicks, so no performance/reliability issues over the expected life of the vape.

SaltwaterReefer said:

and what is the cost difference?

Click to expand...

i can't compare cost to any other design, because in my mind there is no alternative. however, once i had the design nailed down the parts for one cube is about $25 ... now, it took several thousand dollars to get the design right.

Now that you mention that, I wonder what the difference in hit temperature drop between ceramic heating elements and metal coil is. Ceramic holds its temperature better than metal, and the heater is pretty intense. I have to dial it down quite a bit for it to not be insanely hot, but I hadn't thought of air flow and thermodynamics at all.

I hope to sell a few of whatever circuit I come up with built inside of hand blown glass. I am pretty sure I could do what you are getting at with a banana pi or something similar, but that is completely overkill (and expensive). Trying to make a digital circuit like the one you've got is far beyond my skill level and budget.

Do you sell your chips or is it a proprietary thing? And, you said batteries, right. Interesting. I am repairing a plug-in, table-top design this time.

i am doing this open source since it takes me forever to complete a project, and the design is solid and reliable. there is a link to my thread in my signature ... this pre-production version starts around post #940 ... came online in post #954 ... post #1170 has a link to a YouTube video.

How difficult would it be to make the up and down temperature buttons the same kind of radial button as they have in stereos that can be turned infinitely in either direction, like they put in stereos for volume and tuner nobs?

Do you sell the chips or do I need to procure and build it from the parts? I am not confident about reproducing your board printing method.

i think changing from buttons to knobs would not be possible with the simple PIC processor i am using --- not enough input/output pins - i'm using an 8pin chip and only one pin is available for user input. i have a resistor divider that feeds voltage to an A-to-D input to determine which button is pressed. i had 3 buttons for a while, but really had no need for the 3rd button and removed it from this version. this one input could handle 5 or 6 buttons with no problem - maybe even 10.

i don't provide parts, just information about a particular implementation (preferred embodiment, in patent speak).

once i had the circuit figured out, i stopped making my own pcb and outsourced to a pcb foundry --- download free pcb layout software (and learn how to use it), upload the design to their factory (one or two mouse clicks), get the boards a week later. i've gone through four iterations, and one of those had the wrong physical size (measure twice, cut once - but this was a design fuckup) and never got used or tested.

i'm a software weenie - this hardware stuff has been an interesting stretch.

it has been so long since i started down this road, some components are obsolete - for example, the MAX6675 that reads the thermocouple has been replaced. and someone posted a link (in my thread) to a much more compact MOSFET (used to control heater current).

What are the stipulations for using it?

i don't understand what you're asking ... and using which thing?

May I use your circuit design in hand made vaporizers (working toward a hand blown glass enclosure) that I would sell and profit from?

That is the goal when I happened upon you. I was going to figure out how to get one working with the one I am building now, and then start selling them at the drum circle I go to.

If yes, awesome. I am open source as well to the same extent. In software, this is easy. You just leave their licensing agreement in the code you use and give them credit for it. Does it work like that in hardware? If you let me do it, I will print your name and a link to your build thread on the inside somewhere.

If no, I am going to have to find some other way to prevent the temperature drop. I am committed and pretty excited about the plan.

open source hardware and software. if you find something that is useful, please feel free to use it.

i see the links in the first post don't work anymore ... i will post some updated links in this thread tonight or tomorrow. and then try to get access to update that first post in my thread.

a link back to the FC community would be nice.