At Michael's Craft Store in the jewelry making section.
I think it is to make jump-rings. It came with a 2nd one also, that went from 6mm to 10mm.
DNA 40, NR, Nickel Builds
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At Michael's Craft Store in the jewelry making section.
I think it is to make jump-rings. It came with a 2nd one also, that went from 6mm to 10mm.
doh...what am i thinking? yeah with a dual it will halve the resistance... you'd have to make 2x tons of wraps to get up to .10 ohms.
The DNA 40 chip's programming uses the mathematical relationship between resistance and temperature for its temperature calculations so one would expect to see oHms go up and down as the coil heats and cools.
Hey all .... had my DNA40 Hana now for a couple of days, and I am not sure I am liking it.
I got Ni200 28g, did dual coils, 10 wraps on a 3mm mandrel each side, and it's reading at 0.05ohms on the Hana.
I set the temp control at 400 degrees (for cotton?) and I keep getting the temp control kicking in at 23 watts. If I go higher it stutters kicking in the temp control.
I have some 30g and 32g coming, guess I have to get the ohms a lot higher?
If you're below 0.1 ohms you won't get the full 40 watts. But it's interesting to know that you don't need them and still can reach the temperature you've set! So besides the resistance jumping around (which is required) what else don't you like about it?
I think generally we should strife to use thinner wire (30 or 32awg).
Thanks for sharing your experience!
So far it is just really touchy, pulses almost like pulse-modulated mod, cuts off due to temp control, etc ...
BUT I think all of that will resolve when I get my other guages of wire and can wrap coils that will be agreeable to the chip.
So I am waiting on Amazon and the USPS.
BUT I think all of that will resolve when I get my other guages of wire and can wrap coils that will be agreeable to the chip.
So I am waiting on Amazon and the USPS.
I guess the scientist in me doesn't like the idea of the DNA assuming "room temp". Your room temp is going to be different from mine. As long as you adjust the temp setting to taste, the difference shouldn't be a big deal. But if I know cotton flashes at 410F and I set to 400F, then I could potentially burn the cotton depending on what room temp is when I screw everything together.
It's gauging temp by reading the resistance of the ni200... At higher temp the resistance increases...
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There's also an on-board temp sensor. This is used to detect overheating of the board itself, but if I were writing the software, I'd use it to get ambient temperature every once in a while too. 
It would certainly be cool to have a precision onboard temperature sensing gizmo. But I figure that would probably cost $10 more.
Likely not the Nickle wire we're talking about here, but just for reference:
http://www.omega.com/temperature/pdf/ni60.pdf
The key thing here is the "Temperature Coefficient of Resistance", which is 0.00015Ω/°C (20 to 500°C) for the wire in the pdf, and likely different for the Nickel wire Evolv says to use.
So, using this number, the dna40 can do the math and figure out the temperature based on the measured resistance, or rather, the measured current and voltage it uses to calculate the resistance.
Neat idea...now I want to get some Nickel wire and try this out on my Arduino Raptor mod...
*edit*
So the dna40 is calibrated for Ni200 wire.
Found this: http://www.hightempmetals.com/techdata/hitempNi200data.php
So the temperature coefficient of Ni200 is 0.004/0.005 Ω/°C.
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Haha that went over my head just a bit! Yeah the evolv chip is calibrated for ni200. I have 100 feet of 28, 30 and 32 on the way
Anyone else having a bit of a tough time getting these coils to cooperate? Wrapping the coil is easy but if I can't glow it, how am I supposed to know if it's heating evenly and, more importantly, how accurate its heat sensing is? Since the board detects average temperature across the coils, one spot will get real hot while the rest remains cooler, making it seem like your temperature is only X degrees when you could still be scorching cotton/juice.
The Ni200 coils will not glow like kanthal wire builds.
From what I've seen on the few video's you will do some interactive regulating up or down in temp. to get the desired vape... so once you dial that in, you're not going to have scorching.
Well, they certainly will glow if you take off temperature control. What my main issue is, as with Kanthal, coils tend to heat unevenly unless fiddled with. Generally, you fire them and watch them glow and make sure that they heat from the center out and equally. The TC will read the average temperature of the coil and, if the coil is heating unevenly, some spots will be much hotter than others while the average temperature may be at or under your setpoint. Earlier, I had to fiddle around with a coil for a few minutes to get rid of a hot leg that was glowing even with TC -- and yet the device still measured <450f. Obviously that spot was much hotter than that
Ten turns of 28 gauge on a 1/8" drill bit got me 0.17 ohms
Note there's room for a second coil just like that!
Atty is purpose-designed bottom-feeding Nuppin' by pdib.
Note there's room for a second coil just like that!
Atty is purpose-designed bottom-feeding Nuppin' by pdib.
Yeah I think people will have to experiment and share their findings and create a new "knowledge base" especially on the contact coil thingy. Since nickel doesn't form a protective isolating layer of oxide like kanthal / nichrome it seems to me that any kind of contact between wraps would create a short and a hot / cold spot with uneven resistance and temp sensing across the coil. You can just disable the temp (set the temp > 600°F) and have the coil glow to see what happens, if you can create / avoid hotspots with pinching.
Will we now start wrapping non contact coils on screws? The main problem with non contact coils made on a screw is that the coils will even get bigger than they now need to be because of the low resistance.
I wish evolv would create a FAQ or extensive guide from all the experiences the beta group gathered.
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