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Will this temperature sensing bug ever be fixed?


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I recently bought a DNA75 an there is this bug with temperature sensing that is still present since the early days of DNA boards. When you vape and your batteries dies and you replace it, the temperature sensing will be way off. You can compensate by lowering the temperature but it's annoying. The cause for this is that the chip "forgets" the previous cold ohm resistance reading and reads the atomizer automatically as a new coil, so gets a wrong reading. The whole temperature sensing is off until you let it rest for an hour or so.

This can be avoided by locking the temperature but it isn't a great solution.

The expected behavior would be that after the battery gets replaced it keeps using the same ohm reading or asks "new coil yes/no?".

Any chance this will ever get fixed with a firmware update?

Edited by Dejay
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This is a tricky one. It's not a bug as much as a 'there is no good choice':

When it's on, it tracks when you connect and disconnect coils to ask New Coil Yes/No, so the DNA has a good idea of what to do.

You could have put on a new coil with similar, but not the same Cold Ohms. The DNA 75 doesn't know how long the device has been off. The coil is temperature sensing, and it is already hot in the battery swap case, so the measured Ohms will be higher, as you are encountering.

Because it doesn't know how long it's been off, the DNA 75 would have to ask New Coil Yes/No every time it powers up, regardless of Ohms, even if it had been off for a few hours and you've swapped nothing. This would be very annoying. It can't use a threshold, say, "it must be within 5% to assume it's the same", because that would be unavoidably wrong any time you swap to a similar coil at the start of the day, and since the coil may still be hot (due to the tank being warm), it wouldn't necessarily be true anyway.

Thoughts?

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I don't know how others use profiles but I have a profile for each atomizer I use. In theory there could be an option "tie atomizer to profile" so the system knows (or can assume) it's still the same atomizer. It means you'd have to change the profile every time you put on a different atomizer but I'm doing that now and it doesn't really happen that often. Not sure if that makes sense :)

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Since temperature sensing is broken after each battery change and it can even lead to lightly burning your lips (did a few times until I learned) I would consider it a bug, or at least a usability bug when you consider the lock ohms workaround.

For the best solution you could ask how often per week do you people swap the battery on average, how often per week do they chance atomizers, and how often each week do they do both at the same time. I'd argue that people swap atomizers rarely and if they do they swap them when the juice is empty not the battery, so it rarely coincides. Just ask only if the ohm reading is different on startup. Make it an option for different DNA mods that are used differently in regard to batteries.

I think the real reason it hasn't been considered important is that a) most DNA use only USB charging instead of swapping batteries and b) turning it off and on again is a way to reset the device and reread ohm. But the latter is only needed because the DNA lacks a "re-read cold ohms" function.

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  • 2 months later...
On 4/28/2018 at 5:27 PM, James said:

This is a tricky one. It's not a bug as much as a 'there is no good choice':

When it's on, it tracks when you connect and disconnect coils to ask New Coil Yes/No, so the DNA has a good idea of what to do.

You could have put on a new coil with similar, but not the same Cold Ohms. The DNA 75 doesn't know how long the device has been off. The coil is temperature sensing, and it is already hot in the battery swap case, so the measured Ohms will be higher, as you are encountering.

Because it doesn't know how long it's been off, the DNA 75 would have to ask New Coil Yes/No every time it powers up, regardless of Ohms, even if it had been off for a few hours and you've swapped nothing. This would be very annoying. It can't use a threshold, say, "it must be within 5% to assume it's the same", because that would be unavoidably wrong any time you swap to a similar coil at the start of the day, and since the coil may still be hot (due to the tank being warm), it wouldn't necessarily be true anyway.

Thoughts?

@Dejay This issue is resolved on the DNA 75C which implements some sort of a battery and it doesn't forget the resistance upon a battery swap.

@James In regards to ideas for fixing this for the DNA75, what was the cut-off time when the DNA 75 went from sleep to off mode? It is important for my below suggestion:

How about adding the new/same coil question every time the board is powered on, but with the extra check of resistance difference as per the default device setting (it was 25% difference set by default I believe?). That way, when the board times out and the user turns it back on without actually have swapped anything, he won't get asked anything (since at this point -- I believe 15 minutes was the auto power-off time? -- the coil should've cooled down if not completely - enough to be in the default setting range and not trip the new/old question) but when the user quickly swaps a battery, he will get asked the new/same coil question since the coil will still be hot. He would of course pick no -- it's the same coil as he only changed the battery -- and keep his old resistance and accurate temp control. It also covers the scanerio when the user swaps a battery for example in the morning when everything is cooled off - he won't get asked the question, since the device would go -- powered on -> check resistance to old cold resistance -> resistance within *setting* range -> don't ask new/same.

E.g. implemented like this, it should only add the extra new/same question when the user swaps the battery and the atomiser is still hot, which is the fix we're looking for. It shouldn't add the question implemented like this in any other scenarios so it won't affect the other users who don't swap out batteries or other scenarios.

Please do tell if I need to clarify my explanation or if I'm missing any scenarios?

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