It is really trial and error. too soon the ink will stick the the transparencies But even worse too long and it will cure threw the blacked out parts of the transparencies. If that happens this stuff is very hard to get off. Even paint remover wont take off when completely cured. So it is a learning process the first few times. You just have to go at it and learn how your set up is going to work with the ink. My biggest problem now is i never quite get the transparencies lined up correctly. So i am going to start using my alignment holes i made for the double sided boards to align the transparencies.
My First Pulse Width Modulator Mod
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It is really trial and error. too soon the ink will stick the the transparencies But even worse too long and it will cure threw the blacked out parts of the transparencies. If that happens this stuff is very hard to get off. Even paint remover wont take off when completely cured. So it is a learning process the first few times. You just have to go at it and learn how your set up is going to work with the ink. My biggest problem now is i never quite get the transparencies lined up correctly. So i am going to start using my alignment holes i made for the double sided boards to align the transparencies.
Ok, I got my first working device going. I was having all kinds of issues with the round switch body and wanted something to actually vape and test the board with so I finally threw in the towel and put together a box to try it out. The board itself fit good into the switch body but I was having problems with the press fit bottom plate and getting good electrical contact. I will be able to focus on the switch body more now that I have a working unit to play with while working on it. The anticipation of vaping off of this board was just getting to be too much =].
First impression is -- Holy $h!t..... With a 2ohm Boge, maybe smoketech don't remember, I have it turned all the way down and read 3Vrms and it hits like 18V... With my 18650 device i would take a 6 to 8 second drag to get a decent vape with decent heat and good vapor. This thing gave me a hotter hit with a huge plume with about 3 seconds. Also this is a fast drag vs a slow drag. More like you would do with an actual cigarette. I will have to dig out a higher ohm carto to see how well the adjustment works as I can't really turn it up much from minimum with a 2.0.
Ok, Here are the pic's....
The POT actually doubles as the switch. I couldn't figure out how to do it any other way with this board in a box mod. I set the board in and hot glued a bracket for it to push against and used some foam rubber to stabilize it.
This is a madvapes C box. The connector fits in the power jack slot perfectly.
Oooops That's an A/C mod from work. It had a seized exhaust fan so I boxed in an external fan until a replacement arrives... Picasa mixed my pics up... oh well it is a mod after all....
First impression is -- Holy $h!t..... With a 2ohm Boge, maybe smoketech don't remember, I have it turned all the way down and read 3Vrms and it hits like 18V... With my 18650 device i would take a 6 to 8 second drag to get a decent vape with decent heat and good vapor. This thing gave me a hotter hit with a huge plume with about 3 seconds. Also this is a fast drag vs a slow drag. More like you would do with an actual cigarette. I will have to dig out a higher ohm carto to see how well the adjustment works as I can't really turn it up much from minimum with a 2.0.
Ok, Here are the pic's....
The POT actually doubles as the switch. I couldn't figure out how to do it any other way with this board in a box mod. I set the board in and hot glued a bracket for it to push against and used some foam rubber to stabilize it.
This is a madvapes C box. The connector fits in the power jack slot perfectly.
Oooops That's an A/C mod from work. It had a seized exhaust fan so I boxed in an external fan until a replacement arrives... Picasa mixed my pics up... oh well it is a mod after all....
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I will have to build a Zenoss probe to monitor my juice level so i will get an email when the carto is running low =]
Looks great bstedh. I can't wait to tackle this once I give the thread a few more reads and figure out the schematics.
I built a larger scale mock up on a prototype board but never put it in anything. The build with through hole components is fairly easy. Just brush up on your soldering skills a little and have some fun. I am really liking how this thing works.
Ok, after the first day of vaping on this thing. I like it... The battery voltage is down to 7.5V and my pot is adjusted 1/2 way to maintain about 3Vrms. So the one draw back is that you need to keep adjusting as it drops off. For me this isn't a big deal but for others it may be a deal breaker. I will be switching to the 500 and 1K POTs as they will not need to be turned as much to get the same adjustment but I have a feeling they may get a little jumpy after a little time and abuse. These POT's don't appear to be very rugged in the least and I have not been able to find any that would be any better for durability.
The potentiometer issue is what drove me to experiment with the whole microprocessor thing (see the "Processor" thread in the main modders forum). The voltage drop thing isn't as noticeable on dual coils btw, and with a 500ohm pot you move it a smaller amount which probably saves wear and tear. Over two months now with no issues on mine so far.
The hits this thing is capable of pretty much wipe out any downsides to it anyway.
The hits this thing is capable of pretty much wipe out any downsides to it anyway.
that's what I'm thinking even with the 200 ohm. I ran out of dual coils so I am currently puffing only on the 2.0 which seems to be lasting longer without burning it or I just have one of those rare cartomizers that seem to go on for ever...
It's possible it could be a side effect of the pwm, I have an EMDCC I have been using exclusively with this device for 5 weeks now. It still hits great. Fillered carto's (including dual coils) never made it past the two week mark for me before.
Last night I finished putting together all of the boards and reworked the first one that I had several mess ups and bad solder on. I had to get creative to work around a couple of lifted pads and holes drilled to large on one. I started putting together a second box so that I can test the boards without much trouble. I have 2 X 200 ohm Pot boards, 2 X 500 ohm, and 1 X 1K ohm. (who knows how to access the ohms symbol when typing?)
I did notice that it is perfectly fine to reverse the zener and just solder 2 contacts instead of 3. Hopefully they work. I will find out when I get to the testing stage. I think I should have gone with about 6.5V or even 7V zeners. Maybe a quick digikey order is in order.
I think I may have solved my issue with the contact of the press fit switch bodies I was working with. They where too loose so borrowing an idea from the scubagen3 thread I am going to put solder around the outside of it to shim it and make a tight press fit. Have to be careful as the body distorts fairly easy.
One trick I figured out all on my own was that using solder braid that has been flooded with solder works very well for getting a nice tin on the board. Just put your iron on it and slide it around the board slowly and it leaves a nice thin tin on the exposed copper. Just have to make sure to go slow enough to heat the copper. If the braid is running low just throw a blob of solder on a pad and suck it up and continue.
I did notice that it is perfectly fine to reverse the zener and just solder 2 contacts instead of 3. Hopefully they work. I will find out when I get to the testing stage. I think I should have gone with about 6.5V or even 7V zeners. Maybe a quick digikey order is in order.
I think I may have solved my issue with the contact of the press fit switch bodies I was working with. They where too loose so borrowing an idea from the scubagen3 thread I am going to put solder around the outside of it to shim it and make a tight press fit. Have to be careful as the body distorts fairly easy.
One trick I figured out all on my own was that using solder braid that has been flooded with solder works very well for getting a nice tin on the board. Just put your iron on it and slide it around the board slowly and it leaves a nice thin tin on the exposed copper. Just have to make sure to go slow enough to heat the copper. If the braid is running low just throw a blob of solder on a pad and suck it up and continue.
I just found 2 EMDCC unopened in the bottom of a parts box. Forgot that I had them because I quit using them due to the fact that BWB casablanca seems to clog them up fast. So I decided to try them with my BWB coloa on this thin.
Noticed that I am turning it up to about 4Vrms with the 1.5 DC. The initial voltage of the battery drops of quicker but seems to stabilize a little longer in the mid region longer. Of course this is just one evening of vaping wile soldering and not actually measuring the Vrms as I go... Figured I would use the experience meter for a wile and see what I think without confusing myself with facts...
After a couple of days vaping on this board I have found airy is better.
It needs an airy carto as you have to be able to take a quick draw or it will scorch the juice... Not really burn but you can definitely tell it is almost ready to burn. This fast hard draw also increases the vapor production. My DC's don't work so good on it however because my juice has a tendency to gunk up the coil fairly fast making a tight draw which absolutely does not work on this thing. Need to find a good flavor juice that doesn't gunk the coils.
Clutch.. What juice works good for you??
I also got my test box about done. It's almost the same as the one I posted but I will be able to take the boards in and out to test the different POT's. Jut gotta add the atty connector and a wire.
It needs an airy carto as you have to be able to take a quick draw or it will scorch the juice... Not really burn but you can definitely tell it is almost ready to burn. This fast hard draw also increases the vapor production. My DC's don't work so good on it however because my juice has a tendency to gunk up the coil fairly fast making a tight draw which absolutely does not work on this thing. Need to find a good flavor juice that doesn't gunk the coils.
Clutch.. What juice works good for you??
I also got my test box about done. It's almost the same as the one I posted but I will be able to take the boards in and out to test the different POT's. Jut gotta add the atty connector and a wire.
I make my own, it's all 50/50 pg/vg, about 8-12mg nic and I tend to stick with flavors that don't have a lot of coloring in them. Mostly candy/fruity flavors. I have on occasion been known to vape plain juice with no flavor at all, especially if I am testing a new kind of atty or carto.
I didn't find the info, sure it's here somewhere 
Those are 18350's??? I love how you modded the 2-C box. I would have never thought about that! I made a 5v mod with that box, using 18500's .. never thought of putting the batts in sideways .. ingenious!! I've got another of those boxes in my shop, this is giving me ideas!!!
my box with 18350's with the good old stack of nickels trick cause I didn't have any 18500's
By asnider123 at 2011-07-09
Those are 18350's??? I love how you modded the 2-C box. I would have never thought about that! I made a 5v mod with that box, using 18500's .. never thought of putting the batts in sideways .. ingenious!! I've got another of those boxes in my shop, this is giving me ideas!!!my box with 18350's with the good old stack of nickels trick cause I didn't have any 18500's
By asnider123 at 2011-07-09
I'm considering using a 555 on my next mod instead of the OKR, but my only concern is - how is the battery life in comparison to a switching regulator?
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A good switching regulator (like the OKR-T) is typically around 92% efficient at the loads we put on them vaping. That means ~8% of the battery's charge is dissipated as heat through the circuitry. Proper MOSFET selection with a PWM circuit can yield efficiency as high as 98%, even under the heaviest of loads. I've found the relationship between efficiency and run time is fairly one to one. In other words, you should see an improvment in run time of around 6% using PWM over a switching regulator. Keep in mind there are lots of "cheapie" switching regulators with lower efficiencies out there, some as low as 80%. Also, PWM doesn't vape exactly the same since a switching regulator outputs straight DC and PWM outputs a high frequency pulse. I haven't made any comparisons myself, but you may find you like to use more power with one or the other. That will also affect run time.
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Thanks Craig. I find myself vaping towards a higher wattage than most people - 11 - 14+ depending on the time of day with menthol/VG only juice. I wind my coils to 1.5ohms and set my voltage to 4.5+. It seems that the PWM circuit hits harder at a lower voltage, so I may see longer run times.
It's possible. I have not done any vaping tests myself to compare PWM to other methods of regulation. You may be able to use less power to get the same effect. In any case, I'm sure you'll get performance at least as good if not better than a switching regulator. Of course, you need a circuit that can range the duty cycle nicely for you. It can be a bit tricky to dial-in with the 555 since it's an analog circuit, especially if you don't have access to an oscilloscope to check the output.
I've also been going a little higher on the wattage, been vaping around 10W lately. I even crank it up to full blast on my main mod every now and then, 6V with a 3Ω atomzer. Though, the vapes can start tasting burnt on me at max voltage so I don't do it all that often.
I've also been going a little higher on the wattage, been vaping around 10W lately. I even crank it up to full blast on my main mod every now and then, 6V with a 3Ω atomzer. Though, the vapes can start tasting burnt on me at max voltage so I don't do it all that often.
I've been doing a little research on nebulizers and it appears that many of them work on the principle of oscillating the fluid to produce tiny droplets that can then be inhaled into the lungs. My Dr was telling me about this earlier in the year. He said that nebulizers are designed to produce tiny droplets as opposed to an atomizer (like an asthma inhaler) that produces larger droplets and therefore cannot go as deeply into the lungs.
What am I trying to say? A PWM, I think you can legitimately say, is a pocket handheld nebulizer, for it atomizes with a constant frequency variable duty-cycle square wave, causing heat and oscillation (quite sophisticated, really).
So I guess the secret here is deciding at what FREQ your device should operate at. The higher the FREQ, the smaller the droplets (keeping in mind that too high a FREQ will begin looking like DC to the atomizer).
If you refer to this article:
Ultrasonic nebulizers make micron particles
you will see the nebulizer that requires NO HEATED ATOMIZER. Rather than working on the theory of variable duty cycle, it uses variable frequency fed to a plate, either at the bottom of the tank or to a mesh above the liquid. I don't know what the frequency range of the 555 / FET setup is, but I am sure you can take this basic circuit, fixing it at 50% duty cycle, and turn it into a variable frequency modulator.
Cool concept, huh? A mod/tank combo that does not produce heat!!! Who woulda thunk it?
What am I trying to say? A PWM, I think you can legitimately say, is a pocket handheld nebulizer, for it atomizes with a constant frequency variable duty-cycle square wave, causing heat and oscillation (quite sophisticated, really).
So I guess the secret here is deciding at what FREQ your device should operate at. The higher the FREQ, the smaller the droplets (keeping in mind that too high a FREQ will begin looking like DC to the atomizer).
If you refer to this article:
Ultrasonic nebulizers make micron particles
you will see the nebulizer that requires NO HEATED ATOMIZER. Rather than working on the theory of variable duty cycle, it uses variable frequency fed to a plate, either at the bottom of the tank or to a mesh above the liquid. I don't know what the frequency range of the 555 / FET setup is, but I am sure you can take this basic circuit, fixing it at 50% duty cycle, and turn it into a variable frequency modulator.
Cool concept, huh? A mod/tank combo that does not produce heat!!! Who woulda thunk it?
Here's another thought .. as a casual observer I have been learning quite a bit about PWM theory by reading your great posts. I may have missed it, but have noticed that your circuit appears to be oscillating a nichrome heater element at about 400 hz. PWM lighting dimmers work great, but they are running at 60 hz. I am wondering if the heater element in an atty is even capable of handling a freq that high, it needs a certain amount of time to heat and cool and reheat, etc. I am thinking that the wire itself may have an inherent frequency, above which it just constantly remains on (virtually).
Perhaps lowering the FREQ would give better results across the duty cycle. I know, I'm no electronics tech, but I did stay at Holiday Inn express :
Just thinking out loud ...
Alan
Perhaps lowering the FREQ would give better results across the duty cycle. I know, I'm no electronics tech, but I did stay at Holiday Inn express :
Just thinking out loud ...
Alan
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