Some thoughts on control

[kjj]

Broadly speaking, there are four generations of controlled power delivery.

First Generation: No control.
Second Generation: Voltage control.
Third Generation: Wattage control.
Fourth Generation: Temperature control.

Virtually all stock units, and most mods, are first generation. They are either a raw battery, or a battery with some sort of fixed voltage regulator. You have to match an atomizer's nominal resistance with your power supply.

A few are second generation, with user operated voltage control. The ProVari is an example of this. If you change atomizers, you can recalculate your required voltage and adjust it.

As far as I know, the Darwin is the only well known wattage controlled power mod, but I suspect there are a bunch of home brew units around that also do this, I know I'm working on one, or will be as soon as my PCBs get back from the fab. These should be able to adjust automatically to any atomizer resistance, and even compensate on the fly as your coil heats up or accumulates gunk.

There are no temperature controlled mods yet, as far as I know, but work is in progress.

The jump from first to second generation is fairly large, since you need some sort of user interface. The mechanics are pretty easy. Heating coils don't need clean waveforms, and a microcontroller from the 90s can do PWM in its sleep, so you can buck or boost all you want.

The next jump is pretty easy by comparison, you just need to sense the current, calculate the wattage during the ON part of the cycle, and adjust your timing on the next cycle. Some of the second generation units already have a means to sense current, so I see no reason why they couldn't be converted to wattage control with a software update.

The last jump looks like it is going to be painful by comparison. There are big problems with measuring temperature.

The most obvious method is to stick a thermistor inside the coil, or maybe on it. One complication is size, of course. DO-35 is damn small, but I think a 510 atomizer is smaller, or at least similar. Also, you now need a 3 or 4 pin connector. The threaded connectors we've all learned to love have great mechanical properties for devices that get dropped or shoved into pockets, but they can't really be adapted to add extra contacts.

Another possible method is to attempt resistance pyrometry. Of course, this will only work if we know what alloy our coil is made from, and if that alloy has been properly characterized. But woe to the poor guy that wraps a Kanthal D coil for a device that is expecting Nichrome 60.

Incandescence pyrometry is probably going to be pretty rough. An active (laser) device is going to be pretty big, too big even for the people going for 30ml tank mods. I've always sorta wanted to see if I could make a totally passive optical pyrometer using photosensors with different passbands and fitting the observations onto the blackbody curve, but I've never done it, partly because I don't think it'd work very well. Oh, and I don't know if the vapor we are trying to produce is transparent in infrared.

And to top it all off, it isn't known whether temperature control will provide any benefit beyond wattage control. After all, the huge bulk of the vaping public is more-or-less happy with first generation devices.

Any thoughts?

 

[kosliev]

Sounds like over-engineering.

2nd generation and 3rd generation are fairly enough, what needs "upgrades" are the atomizers, and the liquid storage system(s), another welcome thing would be the standardization of connections, along with smaller batteries; even normal, commercial ecigs are still a big hassle to put up with (dripping does cut everything in half though, but along with practicality).

I also have a question for you, you might be able to answer, suppose we have two devices, that output the same wattage, 16Watt, like so:

1Ω coil on a 4V battery -> 4A current
16Ω coil on a 16V battery -> 1A current

assuming everything is handmade and the same (coil material etc), will these two feel the same, vape wise?

 

[kjj]

Well, sorta.

I think they should be very similar to each other, assuming all the other conditions are the same. They will probably be indistinguishable to the user. If we limit the spread to the range of commercial atomizers, roughly 1.8 to 4 ohms, I think they will be identical, as far as the user is concerned. The only way to be sure, of course, is to build a third generation device and test it with some extreme atomizers.

The reason to consider the fourth generation is that the other conditions aren't the same. 16 watts while the wick is soaked is going to be a lot different from 16 watts with a dry wick. In the same way, the difference between a weak draw and a good suck is going to be huge.

 

[breaktru]

Love to see you project as it progresses.
Do you have any experience soldering uMax sized chips?

 

[wv2win]

....After all, the huge bulk of the vaping public is more-or-less happy with first generation devices.

Any thoughts?

I don't agree with this last statement. There is a large population (can't prove it, but I believe it) of those who tried vaping with the crappy small, expensive, auto battery devices that just threw them in a drawer and went back to smoking due the inferiority of the device. I personally know of 10 people you did this, each expressing to me that vaping is just another scam that doesn't work.

Then there are the ones who continue to vape and get just enough benefit to continue but have never really tried anything better and think that all PV's are basically the same other than cost.

I think the Darwin is a huge "leap" forward in vaping technology. One of the biggest issues with vaping is the inconsistency and "hassale" factor. The Darwin is the only device that I am aware of that "automatically" adjusts to the characteristics of the atomizer to provide the best consistency currently available.

 

[SurvivorMcGyver]

I think the Darwin is a huge "leap" forward in vaping technology. One of the biggest issues with vaping is the inconsistency and "hassale" factor. The Darwin is the only device that I am aware of that "automatically" adjusts to the characteristics of the atomizer to provide the best consistency currently available.

 

[SurvivorMcGyver]

Yes - "sensor" control is far far from happening. The cost of the atty alone would prohibit it. -- But then again ... to develop a rebuildable atty with an RF chip - MIGHT (yup) just MIGHT solve a lot of problems with this schema.

Thoughts?

Of course one would need a receiver on the other end

 

[kjj]

Crap. I really want to chortle dismissively about the idea of putting that much complex silicon inside the atomizer. But I can't.

It'd be too big. Unless you have a tank already.
It'd get too hot. Unless said tank is between the coil and the CPU.
There's no place for an antenna. Not that you'll need much when the receiver is an inch away.
And you can't power it without running the atty. But you don't need it when the atty is off, so you can use an ultracap to steal a little power for later.

Hmm. The 12F675 is available in 3mm x 3mm 8-DFN package...

Actually, how about we skip RF, and just pulse one or more IR LEDs around the bottom of the atomizer and pick them up with a phototransistor alongside the connector?

 

[CapeCAD]

The thought of putting RF in my mouth just doesn't sit right, it might just be me. I'm concerned enough with a switching converter sitting that close to my face without proper shielding.

 

[kosliev]

The reason to consider the fourth generation is that the other conditions aren't the same. 16 watts while the wick is soaked is going to be a lot different from 16 watts with a dry wick.

That still is based on the "primitive" concept of sucking on a heating coil with a wick, like I said earlier, before a 4th generation happens, there should be a 2nd generation of atties; thats just my idea though, I'd say the curve of satisfaction VS enginnering in vaping is similar to that of a diode, at one point you're just using so much current to make minuscule gains in voltage. Current is your engineering here and voltage is the satisfaction.

I'm concerned enough with a switching converter sitting that close to my face without proper shielding.

What are the risks? 8-o


-Just reread and the way i express myself sounds like a woman in menopause sorry

 

[rannox]

Well atties really are on a whole new generation at the moment, with the e2 carto mods (map tank etc), the genesis, and the bulli (think thats what its called). They just havent been widely produced yet, more of a mod community deal right now.

Actually for the temperature contol mod, I say the genesis woud be the best atomizer to implement this project in, especially if your planning on putting a sensor inside the atomizer.

 

[kjj]

I don't see it that way. No offense to the guys making their own atomizers, but they are working on the parts of the problem that have already been solved. Er, mostly solved.

Don't take that the wrong way. I love you guys working on better juice storage and better heating. ULRA, to pick one flashy example, is just damn cool. And juice storage is so incredibly bad in stock units that I'd be too ashamed to explain to a layman just how much of a hassle it is to really use these things.

Why do I think that adjustable wattage is insufficient, even though it is miles ahead of adjustable voltage, and in a whole different galaxy from fixed or raw voltage?

Because we don't know a damn thing about wicking.

Ponder on that.

The generations of power delivery, as I see them, are the generations of feedback loops that are progressively less bad than their predecessors. We care about the vaping experience, but we can't measure it. We can, however, measure voltage, or wattage, or temperature, even though we don't care about them beyond the hopes that controlling them will improve the one thing we do care about.

I see the day coming, I hope, when direct coil temperature measurements are used to either adjust the wattage delivered to the coil to compensate for changing conditions in the wick, or to drive a pump which steers the wick towards the proper wetness. Oh, and changes in airflow need compensation too.

Until I see an atomizer with a feedback loop that can be steered in an intelligent manner towards a better approximation of ideal conditions (meaning wetness), I don't see a generational change.

 

[SurvivorMcGyver]

The thought of putting RF in my mouth just doesn't sit right, it might just be me. I'm concerned enough with a switching converter sitting that close to my face without proper shielding.

good thoughts over all kjj

@CapeCAD never pondered the thought of the RF on the mind and body -- I was mostly thinking function (Couldn't be any worse than microwaving your chips -- LOL {inside joke folks}) anyway....

Ponder on Folks. I enjoy exploring new ideas. I more like the challenge of trying to implement them ...... Oh, the Mcgyver in me.... it never stops ....

 

[SurvivorMcGyver]

WillyB where ya at this is your nemesis - is it not?

 

[SurvivorMcGyver]

Ok so we don't want Chromosome (or whatever) damage from RF - so how about bringing in Mighty Mouse or one of its amphenol cousins (the circular connectors)

I’ve been sourcing these for quite some time for several clients of mine and it just dawned on me today – WTF – it’s right here.. If you study the offering thoroughly you’ll find PCB connectability, diode through pins, high frequency handling modules and a multitude of application specific variations – including hermetically sealed connectors, thermocouple accommodating units, etc.

Obviously you’d need a specialize atty and mating connector to accomplish this – but, personally, I see no other sound way of accomplishing temperature control of an atty other wise

Mod on folks

PS. There are several 100 differnt pin configurations available -- you might also find the commercial line available at Mouser and Digikey - to name a few -- (or you can always contact me )

 

[SteelJan]

I'm thrilled to have found this thread. RJJ, you and I are thinking exactly along the same lines. In my mind, we need to move beyond putting a liquid onto a raw coil, shoving a guesstimate of amperage into it from a dangerous lithium battery to heat it to who knows what, and sucking the vapor off of it. Some other way to generate the heat, some other platform to vaporize the juice.

After all, none of us would fry an egg by plopping it straight onto the burner of our stove and then scraping it off to eat.

The thing with the electronic cigarette is that it was originally designed the way it was because it was the easiest and cheapest to mass produce within an acceptable tolerance of safety and reliability. That does not mean it's the only way or the best way to make a consumer-friendly, cigarette-ending PV.

Could the juice be on a tiny stainless steel pan and heated that way? Could the heat be generated some other way than a big dangerous lithium battery and a nichrome coil?

Yes, devices like the Motorola/Freescale 68HC12 can do PWMs (I think, maybe I'm thinking the 500 family or later), but we're still talking about controlling a battery and nichrome wire. I like the laser proposition, but yeah, too big and expensive right now.

I made a temperature probe to see just how hot the coil is while I'm vaping. Looks like 185F is typical by my probe. And it might not be the true temp, but if I'm thinking about a feedback loop, all I need to know is whatever the probe I'm using should be, yes? Oh, I should tell you, I made the probe out of one of those big outdoor grill meat thermometers that looks like a giant fork. Disassembled it and pulled the thermistor out of the fork. I know it's probably going to pop the thermistor by my sticking it down onto my carto coil, but I realized I have to measure the temperature quickly on each vape, so I could not find any tiny aluminum piece or whatnot to stick the thermistor in and still let it register the temp quickly enough.

My next round of experiments, I want to see if I can mount the thermistor into a collar to place around the cartomizer at the coil location and see if I can find an external temperature there that would equate to my probe's internal coil temp of 185F. My thinking for now is that a removable collar could be placed onto any standard-size atomizer/cartomizer. Then the temp could be fed back into a microcontroller and use that to regulate the power.

Okay, I've typed enough and don't know if this makes enough sense, yeah?

 

[breaktru]

Hi Jan, I enjoyed some of your YouTube videos. Very instructional.

 

[WillyB]

WillyB where ya at this is your nemesis - is it not?

Not even worth the trouble of arguing, almost ever point kjj made I disagree with.

His first is the most bizarre.

the guys making their own atomizers, but they are working on the parts of the problem that have already been solved.

 

[AttyPops]

On not mounting sensors inside an atty...

http://www.e-cigarette-forum.com/fo...88-advanced-atomizer-designs.html#post2607252

The thought is that an atty coil (if you still end up using one) is a thermistor of sorts in it's own right, since the resistance varies with temp. Of course it would have to be calibrated. And the variation may be too faint...... But it's on topic and in another thread so I posted the link.

I had similar a thermistor thought before while wrapping a wire on the outside of a needle and running the juice inside the needle until it vaporized. Would have to have a proper insulator. But the thermistor would be on the needle at an appropriate distance to not fry it.

Then I kick myself and remember K.I.S.S. Still haven't even bothered to put an MCU in my mods either. No compelling reason yet......I was going to drive a vv-mcu mod with PWM, and a 3 color LED to indicate voltage by color. Then I realized that a multi-colored thumb wheel pot and an adjustable regulator would replace the whole thing. K.I.S.S. again. Remember that vaping is experiential. And therein is the issue. It's subjective. So you need a human to just "turn the dial". What control issues do you really have? dial-up, dial-down. What's the issue? Even a linear regulator keeps a fairly even voltage until just before cut-off. Meh.

 

[jonboyusmc]

I'm with Willy on this one. I don't agree with anything on here. You're still trying to power the same nichrome coil with different power sources, or with RF and lasers. Atty design need to take a huge step forward, before power sources in my opinion. You're also missing the big picture. MONEY!!! I for one am not going to shell out $500-$1000 dollars for a new power source, no matter how well it performs. Hell, I won't pay $229 for a Darwin, because it's still powering the same attys/cartos. I would happily give $30-$50 for a better atty any day of the week. Just my $.02