I got my VS dna 40 today. I wrapped 30g ni200 14 wraps on a squape reloaded. I blue flamed the coil and got them as tight as I could. My shark reads .52. I used cotton from cvs. Set temp at 430 and watts at 14. Very nice vape. Gonna try to twist some 30g then use 10 wraps. Should make them easier to work with.
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The dna-40 does not directly measure temperature at the coil, it measures coil resistance. Nickel has a very predictable and relatively linear increase in resistance as its temperature increases - most materials do the same, but the change in resistance with nickel is substantially larger.
When it checks "New Atomizer", it records the current resistance of the atomizer. The board assumes the coil is at 70°F/20°C, and sets it as a reference. After this check is complete, the reference point does not change, regardless of temp changes.
If the coil is chilled after this check, the current resistance of the coil will be somewhat lower (usually less than .1 ohms). However, the reference resistance does not change. It may take slightly longer for the coil to heat up from a colder temp, but the temp control will still kick in at the same point (resistance) as before.
Hitting a cold atomizer will change the vapor temperature, flavor, and density, regardless of the specific temperature at the coil, as air temperature and liquid temperature/viscosity have an effect.
BOOM!
No, you don't want the base resistance to change. It senses the resistance during firing. That base resistance gives it a map that tells it (at x resistance the coil is at y temp). Regardless of the ambient temp the coil will still be the exact same resistance at the exact same temps as long as the base resistance stays the same.
Fwiw, I too had these kinds of issues with my first board. If I went outside and 5 minutes or so had passed before I fired it it would reset the base resistance to a lower value, which means my tp would kick in way sooner. Kinda the exact opposite of what others are experiencing here. If my tp was set for 450 it might only be reaching say 300 and give me a dismal vape. I believe because the box had more mass, so it stayed warmer and didn't cool as fast as the atty.
Every time I picked up the device after a rest it changed the base resistance. Sometimes higher sometimes lower. If higher the vape got hotter, often times burning, if it got lower the vape faded and got crappy.
On my 2nd board the resistance doesn't seem to change. And the vape is always exactly the same regardless of the ambient temp.
I've said it before and I'll say it again. I think there are boards out there that have this same issue that causes the screen glitch, but not bad enough to actually glitch the screen. Yet still causes it to exhibit the other very strange behaviours.
Hmm. Why do you think so? I really don't want that to be true lol. Because that would make trouble shooting even more difficult. I think the only issue with the glitched chips is actually the reset that messes up the base resistance. So far everything that I've seen with my own chip can be explained by that or connectivity issues. Does anyone have a chip that doesn't have the screen glitch but does reset after about 5 min? (shows "Evolv DNA40" on first fire). If so then you are terrifyingly right!
BTW my titanium wire build holds up very well so far. No resistance changes and temp protection works fine. So well that I'm too lazy atm to wire up my second chip haha.
It's hard to say whether this base resistance reset problem is the board or not. In my case, it definitely seems to be the build. I had the same symptoms some of you are having. Seemed to be vaping fine for a good while keeping the Base resistance as it was when first built, then after coming back to it, base resistance had changed and vape changed. I thought it was the board, resetting it when not at room temperature therfore it's calculations for temperature were out. But after messing with builds and ensuring solid connections, it's worked flawlessly, never reset the Base resistance on any given atty. I've just rebuilt my orchid v1 with a dual twisted 32 gauge ni200 build and it's given me the best vape yet, and the connections are more solid as there is 2 leads instead of 1.
Edit: please ignore the wonky posi post, didn't have my pliers to hand at the time but rest assured, it is very tight!
Edit: please ignore the wonky posi post, didn't have my pliers to hand at the time but rest assured, it is very tight!
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It's hard to say whether this base resistance reset problem is the board or not. In my case, it definitely seems to be the build. I had the same symptoms some of you are having. Seemed to be vaping fine for a good while keeping the Base resistance as it was when first built, then after coming back to it, base resistance had changed and vape changed. I thought it was the board, resetting it when not at room temperature therfore it's calculations for temperature were out. But after messing with builds and ensuring solid connections, it's worked flawlessly, never reset the Base resistance on any given atty. I've just rebuilt my orchid v1 with a dual twisted 32 gauge ni200 build and it's given me the best vape yet, and the connections are more solid as there is 2 leads instead of 1.
Edit: please ignore the wonky posi post, didn't have my pliers to hand at the time but rest assured, it is very tight!
i just did a triple twisted 30 gauge 7 wrap single coil thats been working quite well i tried to do dual coils but it said resistance was to low so i took one out now im enjoying my banana nut bread juice
Nope happened again... ...... Evolv is sending me another board
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This is wierd nevertheless. I spoke to a store owner today and from the 150 boards he sold since evolv launched them, only 3 where returned with the freezing / garbled screen issue.
You guys must have been getting some bad luck with the boards?
It's definitely wierd.
I'm about to jump on one for myself (came in last week) but all these problems I read are scaring me
Regards
Tony
Sent from my GT-I9195 through Tapatalk
You guys must have been getting some bad luck with the boards?
It's definitely wierd.
I'm about to jump on one for myself (came in last week) but all these problems I read are scaring me
Regards
Tony
Sent from my GT-I9195 through Tapatalk
I don't know the interval for it's sleep mode, but at a 3 hour interval it displays the Evolv screen and it had changed the resistance. Lower in this case. My 0.24 build became an 0.22
I then reset it myself manually without any use and it went to back to 0.24
I then reset it myself manually without any use and it went to back to 0.24
Hmm. Why do you think so? I really don't want that to be true lol. Because that would make trouble shooting even more difficult. I think the only issue with the glitched chips is actually the reset that messes up the base resistance. So far everything that I've seen with my own chip can be explained by that or connectivity issues. Does anyone have a chip that doesn't have the screen glitch but does reset after about 5 min? (shows "Evolv DNA40" on first fire). If so then you are terrifyingly right!
BTW my titanium wire build holds up very well so far. No resistance changes and temp protection works fine. So well that I'm too lazy atm to wire up my second chip haha.
I only say it because many of the behaviors I've seen described mirror many of the same ones I was seeing with my first board that did glitch. I've also seen the glitch described with various levels of severity. Some like my first one glitch horribly at generally the first fire of an atty. Others only here and there, and the glitch itself seems to have various renditions. In my case it locked up the entire screen and garbled it till it was completely unreadable. I've seen other reports where only portions of the screen garbled and didn't lock up entirely, etc. The resetting of the base resistance is one thing. But think about it, let's take this recent description. Even if I force a reset of the base resistance. I take my DNA40 out in the cold and let it sit for a while. I fire it after a battery swap and it resets the resistance. The base resistance is now going to be lower than what it is at room temperature. Even if the DNA40 is warmer (say still at room temperature) what should that produce? It should produce a vape that is much lower temp. Once that coil heats up it's going to think it's much hotter than it really is. Vapor production should fall off drastically. If the room temp of a coil results in say a .15 resistance, and it gets reset lower, let's say .14... If the coil climbs say .1 ohm for every 100 degrees, then normally at 470 degrees it would be around .19 ohm... On the other hand, if it thinks it's base is .14, then that same coil is only going to now climb to .18 before the TP kicks in. Only reaching 370 degrees.
But that's not what's being described. Instead it's being described as though if it's set for 450 it's being allowed to reach say 550 or 650 or whatever. A hot burnt vape compared to normal. That just doesn't add up with temperature shifts, and it certainly doesn't correlate with what I've seen out of my own second board. It does however match up with what I saw with my first. It would often times after sitting for 5 or 10 minutes start producing a vape that was way hotter, often times burning compared to the original.
Some of this could be caused by poor connections. But then temperature wouldn't really be a factor. If a coil is say .11 ohm, but a poor connection ends up making it think it's a .16 ohm coil... Now the TP is going to blast it way hotter.... ASSUMING that connection gets better... i.e. maybe as the coil heats up it causes the connection to be good again. But again all in all the normal behavior for the chip doesn't seem to explain some of the things that are being described here. That's what really makes me wonder if some of this really odd behavior is caused by the same issue that causes the screen glitching but it's just not severe enough to cause the actual glitch on the screen. Like I said, all I know is that many of the things I've sen described are all behaviors that only my first board exhibited whereas my second one has done none of these things.
I read everyones replies.
I agree with the correction that it is measuring temp at the coil. Not sure if first post was miss worded or not.
The assumed 70 degress is interesting. If you were in a much cooler enviroment and swapped the battery or screwed in a cold atty that was at that temp, I'm guessing temp protection would be off by that amount?
Say you did that at 40F. Now it thinks 470F is 430F?
Or say I'm out on my porch or out in the Florida sun and decide to swap atomizer or the battery. It may be 95F ( or hotter device wise due to sun ). Now it's off by 25F the oppsite way.
Why not use the onboard temp as a reference and reset the resistance after X minutes of no use. It's doing this now on deep sleep ( but not to accurately it seems ). I don't know the difference between a screen sleep and a full device sleep though.
Edit: What I mean is use the idled board temp as an offset reference for the coil resistance detection. Not a hard set 70F
I agree with the correction that it is measuring temp at the coil. Not sure if first post was miss worded or not.
The assumed 70 degress is interesting. If you were in a much cooler enviroment and swapped the battery or screwed in a cold atty that was at that temp, I'm guessing temp protection would be off by that amount?
Say you did that at 40F. Now it thinks 470F is 430F?
Or say I'm out on my porch or out in the Florida sun and decide to swap atomizer or the battery. It may be 95F ( or hotter device wise due to sun ). Now it's off by 25F the oppsite way.
Why not use the onboard temp as a reference and reset the resistance after X minutes of no use. It's doing this now on deep sleep ( but not to accurately it seems ). I don't know the difference between a screen sleep and a full device sleep though.
Edit: What I mean is use the idled board temp as an offset reference for the coil resistance detection. Not a hard set 70F
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I'm pretty sure that's exactly what it does. I don't think it just uses a base temp as what it expects the coil to be. It's (when reading base resistance) expecting the coil to be the same temp as the board.
I'm pretty sure we are assuming the chip is smarter than it really is. There are only so much bits available on it that you can't produce too high elaborated code.
I remember back in the rc days when I was involved in a new gyro development (which are more complex than these boards) and there was a hefty discussion about a simple flashing led because there wasn't any room left to code the flashing.
I don't know what chip is on board but calculating heat from a set resistance, measure the resistance, display, memorizing base resistance, temperature inference etc etc, I would bet that there isn't much space left especially when you have to chain the conditions based on a inference between base temperature and on board temperature. There might be other limitations we have no idea about.
I'm just saying that the algorithm behind all this might be simpler than we think.
Regards
Tony
Sent from my GT-I9195 through Tapatalk
I remember back in the rc days when I was involved in a new gyro development (which are more complex than these boards) and there was a hefty discussion about a simple flashing led because there wasn't any room left to code the flashing.
I don't know what chip is on board but calculating heat from a set resistance, measure the resistance, display, memorizing base resistance, temperature inference etc etc, I would bet that there isn't much space left especially when you have to chain the conditions based on a inference between base temperature and on board temperature. There might be other limitations we have no idea about.
I'm just saying that the algorithm behind all this might be simpler than we think.
Regards
Tony
Sent from my GT-I9195 through Tapatalk
Actually you'd be surprised... I program and build devices with MCU's all the time... The Atmel ATMEGA series is one of my favorite chips to use... To give you a rough idea... The ATMEGA16
16Kb flash memory (that's a TON of room when you're talking about machine code)
1 Kb SRAM
512B EEPROM
16Mhz operating frequency
8-bit CPU
32x8 working registers
1 SPI (serial port)
8 ADC channels (analog to digital)
1 analog comparator
3 Timers
4 Output channels
1 Input capture channel
4 PWM channels
32Khz real time clock
131 Instructions in the CPU set
etc...etc...etc...
That single MCU has FAR more power and memory than several of my first computers... and as for size???
7mm x 7mm
Yeah... These days when it comes to functionality I NEVER consider "it wasn't possible due to code size limitation" as even a remote possibility unless maybe you're trying to program skynet.
EDIT: Heck for that matter the series that I use is available in the 44M1 / DRQFN packaging... So imagine, 128Kb flash, 4Kb EEPROM, 16Kb SRAM, 20Mhz clock frequency all in a 5mm x 5mm package!
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im not sure what the board is doing as far as working in cold climates but i have been enjoying my orchid with triple twisted 30 gauge coil tp @440 .09 ohm 23 watts until today its 23 degrees out and had to go to town my dna 40 was in my coat pocket like 5 minutes i started to take a hit and could tell right away i was going to get a burnt hit so i stopped looked at it and now it was .29 ohms and fluctuated between .23 and .29 i had to turn watts down to 13.5 and tp to 390 to vape it out in the cold. this is opposite of what id think it should do anyways i started thinking maybe my coil loosened up because of the big swing in resistance but after letting it sit at home it reset back to my original .09 and its vaping normal again watts back at 23 tp@ 440. just wanted to share my experience as it was just like others have reported. dont know if this is a bad design or just the way it was designed to work. as it is its not an out and about devise but works great indoors.
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