Small change to boost output:
Corresponding software update as of today on OpenSourceVaping at GitHub: https://github.com/OpenSourceVaping/OSM1
I was masking off the compliment of the bits I was interested in. Now that it's fixed it works great. Duty cycle goes from 0..~50%. The extra resistor moves the range returned by the Spectra up a bit. Still not sure why the Atmel ADC is only seeing about half the range I am interested in...
Here's a Mathematica script to estimate power output:
Manipulate[
Module[{vrms, duty, watts},
"Coil Ohms=" <> ToString[ohms] <> "\n" <> "Volts=" <>
ToString[volts] <> "\n" <> "Duty Cycle = " <>
ToString[N[duty = (dc)]] <> "\n"
<> "Vrms = " <> ToString[vrms = N[volts*Sqrt[duty]]] <> "\n" <>
"Amps = " <> ToString[amps = N[vrms / ohms]] <> "\n" <>
"Watts = " <> ToString[N[watts = vrms*amps]]], {volts, 2*4.2,
2*3.7, -.1}, {dc, .001, 1, .001}, {ohms, .12, 2, .01}]
The only tricky calculation is the Vrms relative to a pulse. Other than that it shouldn't be a problem to convert this to any other language.
Ultimately the code on OSM will dynamically sense the coil ohms and adjust the power output. This is something the PrimusZ did (unfortunately at higher power the built in batteries didn't really last). Effectively this provides accurate power levels and "temperature control" because if we periodically (say a few times a second) sample the coil ohms and adjust we keep the same power output regardless of any coil resistance changes.
Using this we get about 200W with a fresh set of batteries and a MELO 300 .17 ohm tank:
The MOSFET should allow us to get up to about 400W. However, the MELO seems to just barely handle the 200W before the juice gets jumpy.
If anyone is interested I have the Eagle layout for the power sleeper board.
OSM #2 will likely use the Atmel sleep coupled with a wakeup triggered by the SQ-MIN-200. That way we can shut off the radio and ourselves when "not in use."
Corresponding software update as of today on OpenSourceVaping at GitHub: https://github.com/OpenSourceVaping/OSM1
I was masking off the compliment of the bits I was interested in. Now that it's fixed it works great. Duty cycle goes from 0..~50%. The extra resistor moves the range returned by the Spectra up a bit. Still not sure why the Atmel ADC is only seeing about half the range I am interested in...
Here's a Mathematica script to estimate power output:
Manipulate[
Module[{vrms, duty, watts},
"Coil Ohms=" <> ToString[ohms] <> "\n" <> "Volts=" <>
ToString[volts] <> "\n" <> "Duty Cycle = " <>
ToString[N[duty = (dc)]] <> "\n"
<> "Vrms = " <> ToString[vrms = N[volts*Sqrt[duty]]] <> "\n" <>
"Amps = " <> ToString[amps = N[vrms / ohms]] <> "\n" <>
"Watts = " <> ToString[N[watts = vrms*amps]]], {volts, 2*4.2,
2*3.7, -.1}, {dc, .001, 1, .001}, {ohms, .12, 2, .01}]
The only tricky calculation is the Vrms relative to a pulse. Other than that it shouldn't be a problem to convert this to any other language.
Ultimately the code on OSM will dynamically sense the coil ohms and adjust the power output. This is something the PrimusZ did (unfortunately at higher power the built in batteries didn't really last). Effectively this provides accurate power levels and "temperature control" because if we periodically (say a few times a second) sample the coil ohms and adjust we keep the same power output regardless of any coil resistance changes.
Using this we get about 200W with a fresh set of batteries and a MELO 300 .17 ohm tank:
The MOSFET should allow us to get up to about 400W. However, the MELO seems to just barely handle the 200W before the juice gets jumpy.
If anyone is interested I have the Eagle layout for the power sleeper board.
OSM #2 will likely use the Atmel sleep coupled with a wakeup triggered by the SQ-MIN-200. That way we can shut off the radio and ourselves when "not in use."
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