BaKx (heating principle) inspired desktop vape

CaleidosCope

Well-Known Member
I tried another stem. 8.5mm OD. It takes way longer to produce vape in my 14mm chamber. Taste ist not comparable; of course with many draws at rising temps I get many terpene profiles. 10 draws +.
My 13mm stem gives 3 to 5 good tokes with less restriction.

With those high temps I use the vapor "feels" different in my lungs compared to any ball vapes I used. AND: I don't need to cough a lot. I reminds me to combusting. I left the 220°C-230°C range because of coughing. As I was combusting I didn't care about temps anyway. And coughing was no big deal - thanks tobacco.

EDIT: And because I just looked at it... It really reminds me a lot of smoking a joint because if I inhale very slowly or very quickly, the situation changes significantly. You can feel it and taste. Maybe someone with an unregulated vape (Nomad, Toad...) can tell us something about this topic.

The conclusion from the test is that there are many conditions involved here. First of all, it's not just about the heat in the oven - that's not enough. There are also many other important components. Among other things, how much distance do I have between the heating chamber and the mouthpiece? Also, how thick is the wall thickness of the glass. How fast do I draw. How big is my herb chamber. Then how deep do I put my mouthpiece into the heating chamber... The smaller the system, the greater the effect of the smallest change. It's really fun.

EDIT: Somehow it reminds me of that mini steam engine that CEOs must have on their desk and screw around with ;)

 
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highvaper

Well-Known Member
how much distance do I have between the heating chamber and the mouthpiece

I think this affects the taste so much - as it cools past a certain point the taste drops off maybe i need to trim the 10mm ID one down and test it more but not sure my jars can take it as when full is about 0.5g

I know what you mean about the different temp feel and the joint like experience - when i finally stopped combustion it was due to me moving to a dynavap (i did have a volcano for years) - just wish i had this to move to instead as its the closest thing so far to a joint for me.

I have been doing a bit of messing with the PID tuning and have come to the conclusion that the D part is probably not that helpful and seems to just fight with the P & I - from research D is more useful for slower processes where its more important not to overshoot the setpoint.

Also trying to tune it for normal heating up AND to a heavy inhale isnt really doable as they are two completely different situations like swimming in a still lake compared to a fast river. For the 6mm & 8mm ID stems it does a pretty good job but with the 10mm the temp drop in the tube can be over 20C and if you keep inhaling the PID will overshoot trying to compensate when you stop inhaling. Maybe for the 10mm stem i need more thermal mass like some glass beads around the stem but would need to move to the 24mm or 30mm tube to fit them in.

The setup is very tunable - but you can get very consistent vapes - but you do need keep to the grind constant and how hard you pack the stem is very important as these affect things a lot as well.

I have found using a stanley knife blade to finely chop bits from bud and then manually poking them into the stem produces a nice draw and vape with the 6mm stem - with the 8mm one being able taking a bit harder tamp before the draw is too tight.
 

CaleidosCope

Well-Known Member
from research D is more useful for slower processes
from my research the simpelst explanation is: D predicts the future in seconds. "What would that temp be from my information now in 3 seconds?"
I use it after I tuned the P and the I.

Meanwhile my wired 25mm long heater got a "don't burn your fingers"-housing and a wrap with a 0.3mm Titanium-foil for more stable temps (but it is still dancing in a 15°C range up and down). More tuning is required. Now it looks a little well-behaved. Before it was type of "dangerous - this guy knows what to do!" ... you can't have it all. ;) - housing improvement to come - the repairability right now is like with Apple products. Glue everywhere. :rockon:

Terpy dreams.

 

highvaper

Well-Known Member
from my research the simpelst explanation is: D predicts the future in seconds. "What would that temp be from my information now in 3 seconds?"
I use it after I tuned the P and the I.

Have a read of the below article as i found it explains D very well.


Out of interest what PID controller are you using?

Your build is looking great.
 

CaleidosCope

Well-Known Member
... Sinotimer MT-S ( I love the white and blue digits - and hate the grey housing ;) ) or this ...or else- exchanged the mechanical relay (the clicking sound is annoying - while "r" is 1 in my settings) and trigger a 8a-SSR with the SSR outputs.
My first build, with a Shelly1 inside... the daily driver is smaller - used a ShellyPlug as a timer/switch:
https://fuckcombustion.com/threads/ballvape-rack-iteration-evolution.53676/

To get cheapo I am thinking about avoiding plugs. Housing for the Sinotimer: 3D print. Screw all the wires to the PID. Restricted; but I don't often change the PID/Coil combination. Some controllers have a lot of free space in the housing... for the 8A-SSR and a fuse!!! ;)
 
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highvaper

Well-Known Member
Not really done much recently other than tuning the PID for the 3mm nichrome and 20mm tube and lots of testing :) - the git repo has been updated with the pin, tuning and heater settings to the top of main.py to make things simpler to setup and more in one place.

I did look at nozzle end for rockets - https://en.wikipedia.org/wiki/Rocket_engine_nozzle in relation to stems and how the air exits

Just wondering if anyone has put a nozzle at the mouth end of the stem so that the air spreads out in the mouth and cools there as it expands - or have a smaller diameter inner tube with the nozzle shape and a slightly wider one around it as the mouth piece so only a cm or two or so is wider and expands just before you breath it in

I have drilled a holes in a couple of the 18mm tubes and will see how that works out with the thermocouple inside as I have only done that with the 20mm tube and quite liked the 18mm tube feel.
 
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highvaper

Well-Known Member
Cool wood working skills - need to do some kind of wood cover for my tubes but dont have the tools or space.

I have been playing about with some 3mm glass beads and the 8mm ID stem. The weed chamber part is on the right.


Conclusion is that it cools the vapour quite well but also kills the flavour so a no no for me.

I may try the balls with the 10mm ID stem for their cooling as I tend to have a few of the 8mm & 6mm stems to about 210-220C and then revape at 220-240C with the 10mm one once the flavours have gone. I may try and make some kind of cage and use them outside the stem in the tube so it works like a ball vape and use the built up heat to breath through instead of the empty tube.

Also i may mess about with the 30mm & 18mm tubes with the balls between the two tubes and the element on the 18mm one so they act as a heat sink as well - this may be a good idea for battery powered so the heat isnt just lost and would reduce battery use once up to temp.
 

CaleidosCope

Well-Known Member
With pleasure. Tomorrow I'm flying to the island of Madeira, Portugal. I think I'll have enough time and material there to post a video. A little patience please. ;)
…uhhhmmm… Little More Patience please… Portugal delivers tons of weed to the rest of Europe, but if you ask polite, they look at you like an alien. Even with prescription. so if you ever try it like me stay 500 km south on the Canaries and you will be happy. But the island madeira is really beautiful. So give me five days to return. And I promise you get a video. (but they smoke cocaine of foil in the parks …that’s OK)
 

highvaper

Well-Known Member
Not posted about the pid/vape design in a while as all i have been doing is just vaping with the 20mm tube - its become my daily driver - i used the TM2 for a few stems the other day and it just doesnt cut the mustard in the same way for me anymore.

I drilled some holes in a couple of the 18mm tubes a while ago but just hadnt got around to nichoming one up and adding a thermocouple but had a bit of free time earlier today and made one with some 3mm nichrome.

Been testing it for the past few hours and so far i think may be the best one so far - the 20mm may be a bit too wide so there is too much of a gap between the straw and the walls so only the part of the straw touching the outer tube heats - in the smaller tube it seems to heat up the straw more evenly and faster. Also when inhaling the 18mm heats the air better so you get better vapour and you can pull harder too. Heats up in under 20 secs as there is over 100w over the smaller tubes surface area.

Need to try with the 16m tube again with the thermocouple inside - but maybe with the 4mm nichrome and only a few turns with the aim of using with batteries for portable quick use but need to keep resistance low or the batteries will just get zapped after just one session.
 
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highvaper

Well-Known Member
Oops was vaping a bit too much and with the 18mm tube and just under 1 ohm element set to 70% max duty cycle and was drawing too much through the LR7843 MOSFET for too long - saw a bit of smoke and then the mosfet detached itself from the pcb with a nice pop.

Have adjusted the the duty cycle to max of 60% as i think should be within its working limits.

If i kill another LR7843 i may then use it in conjunction with those 400w mostfet modules which arent optically isolated (so i think killed one of the picos) and just use the LR7843 to trigger one of those.
 

highvaper

Well-Known Member
Looks pretty rapid 270C! I can see why you need the water adaptor.

Have you managed to combust it yet?

FRiES as in fries the weed? I had an idea for a name for mine - Hot Hole - just dont put a finger in
 
highvaper,

CaleidosCope

Well-Known Member
Looks pretty rapid 270C! I can see why you need the water adaptor.

Have you managed to combust it yet?

FRiES as in fries the weed? I had an idea for a name for mine - Hot Hole - just dont put a finger in
I dont really use the waterpipe adaptor. It was just for showing in the video. I love my bent-glas-bead-tube-direct-hit.

Combustion... i was really close in the beginning :rockon: "draw harder". It must be a little more than 270°c, about the sluggishness of the temp-control.

Naming was a nobrainer... the weed is fried... get me FRIES... its on every fastfood menu card all over the world...even babys know FRiES, but that are not my target consumers... and at least i got a really deep conections to the name... it is my family name. ;) (... i assume you pronounce it wrong...:rofl:That´s OK)
 
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highvaper

Well-Known Member
After reading the unregulated thread i decided to give the setup a go with the pid set to 300 and just run it with the manual overide so is on demand rather than session.

Worked well up to when i didnt realise how hot it was getting as i was using a water adaptor and needed two hands to hold it and the stem and somehow press the button and couldnt see the screen properly and hit combustion point - had a coughing fit after my first lungful of something combusted in a ages.

So not sure i will be messing with it in manual mode or if i do set the pid to 260 or there abouts to limit the chance of combusting.

Otherwise not much code updates done as its all working pretty well - the only pain is the pid tuning when changing coil/tube setup but i seem to have it tuned pretty well at the moment and have a better feel for tuning them now - i still need to do some smaller tubes so i can look at a battery setup again but hoping to share something more exciting in the pipeline in the next week or so.
 
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highvaper

Well-Known Member
I have been using the box version of the setup a fair bit until for i cant remember how many times i had to re-solder on a wire after opening it up to plug in the usb cable - so moved back to the bread board version and again with the odd loose wire or knocking one out could occasionally need a bit of a debug as to why it stopped working or why the thermocouple module has issues as its very sensitive. A friend also saw the box version and asked if i could make him one - i dread to think of having to repair that as well - so as mentioned have been working on something more exciting:


Its a pi pico hat/shield with a max6675 included and headers for everything else it only needs connections for power, thermocouple and heater control. So can be used for any type of vape diy build without needing any soldering and should be pretty much plug and play. There's also a diode to hopefully save the pico from the power being wired incorrectly - a nod to all the TM2 owners who have made that error.

I did think of making a pcb with the screen, pico RP2040 chip etc all on it but the current design allows for it to be used for other non vape stuff and was a lot simpler to do, maybe a future version will be all in one board. All plugin components are cheap, easy get and plugin if any break rather than replacing the whole thing.




The unused pins are all avaliable so there are plenty of gpios still usable (including the adc pins so will be able to check on a battery voltage level for portables) - if the dial or screen isnt required its pins could be used for a second thermocouple/pressure/humidity sensor for example.

I have had a few manafactured and already messaged people who I know bought components for a bread board/soldered version as i feel guilty now they have got all the bits and will have the same pain as I have soldering it all together - also i could do with some more testers as I have had a few ideas for v2 already but could do with other peoples input as once the pcb has been made you cant change it!

It should be able to be used with pretty much any mosfet or solid state relay like in most PIDs eg:
https://www.amazon.com/SSR-40DA-Single-24-380V-Temperature-Controller/dp/B09NPPLDDT - so i think is able to control a standard 110/220v coil but not tried that out yet. Its possible to use a relay with it but the pwm frequency would need to be lowered to accomodate for the mechanical switching speed.

Gotta say when i plugged in the battery after loading up the code and it all worked was a pretty sweet moment.

 

highvaper

Well-Known Member
Well already got some ideas for V2 but am so happy with V1 and the lack of wires or fiddling.

Minor update to the code in case anyone is using it with main.py on the pico - when booting up if you hold down dial or if you have a separate switch it will disable the watchdog (you should hear multiple beeps when booting) this lets you then ctrl+c in thonny and it not rebooting and going in a loop and stopping you from uploading updated code.

I have sent a couple out now and not sure what to do with the rest - am thinking of sticking some on ebay as i think a little thermocouple pico hat/shield would be of use
 

highvaper

Well-Known Member
I needed to do an order for some bits and spotted this little neopixel ring which looked like was the perfect diameter to sit on top of the tube so just couldn't resist getting one as they are pretty cheap and have pimped the tube.


Glow effect:


A chase effect:


It starts at 150C at blue and moves through the spectrum towards red at 260C - i did start it at a more purple colour but blue looked colder.

Unfortunately its hard to film and the colour change isnt really clear on the video but is more vivid than it shows.

Not sure how long i will keep it in place as it does need 3 extra wires and it is only balanced at the top of the tube for the time being - pretty cool how you can control a load of leds with just 3 wires though. Maybe once i make better housing for it all i'll make it more permanent - perhaps a less binged up version.

Have blown another one of those tiny mosfet modules i think due to me messing with temps at 260C for a while so it was working hard when I was experimenting with the led ring - at under $2 a pop im not fussed is more the hassle of soldering it all together so am going to do two in parallel and hopefully that can handle it better.
 
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highvaper

Well-Known Member
Note to any one else who is pissing about with mosfets and killing them regularly - they dont like being shorted.

I made a nice little arrangement of two of them really nice soldering job - most happy with my efforts when i was done.

Wired it up and all looked ok - plugged into the heating element and bang top one smoked within a few secs and then the second as well.

So checked the coil with a multi meter to confirm all was ok and got a reading of about 1.3 ohms.

I was like wtf and decided to use one of the optical isolated ones to drive one of the 400w ones instead and assumed i had a bad couple of the optical ones or one bad one had affected the other. Quarter of an hour later and i had killed both of them as well.

Again another wtf moment and dropped the pwm down to max of 30%. Soldered up another optical isolated one and tried again - i had my finger on the mosfet and power so as soon as it got hot i switched off the power - only took a second - so realised there had to be a short somewhere and yes it turns out there was a tiny split in the insulation and it was somehow shorting but wasnt showing up with the multimeter.

Annoying as i had just placed an order for new bits and when doing so did a check to make sure i had some of them spare - i did about 5 of them and now just the one.

So be careful out there as they really die quickly if they are shorted.
 

highvaper

Well-Known Member
I finally put it all into Box V2


Currently powered by 12v mains power brick but will look at batteries again.

Whats in the box?


So much neater and no soldering other than the mosfet / power part but thats part of the vape side of things. I see the setup as 2(3) different parts.

1. The lower power 3.3v electronics - up to the pwm output - including software.

2. Vape + high power electronics - from where the pwm leaves off so the mosfet/relay + whatever you want to control with the pid - in my case the nichrome and tube but could be for a steel element vape like the TM2 or ceramic oven type one or even a coil.

3. Power - how the heater is powered - this would also cover supplying a safe voltage to the pico - I think the LM2596 dc to dc convertor seems to be doing a good job with different inputs and keeping a solid safe 4.5v output for the pico - im using 4.5 as i needed a bit more than 3.3v for the neopixels and the pico is safe up to 5v.

Im pretty sure with a fully customised pcb with a RP2040 chip, screen and thermocouple would be basically be just the size of the screen - would almost just be like a large switch on the cable. There are smaller hats/shields the size/shape of the pico - i think one of those would be possible so would be much smaller than the current pcb but less versatile.
 
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