this post was submitted on 27 Jul 2023
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Being able to measure open circuit battery voltage is great, but it would also be useful to measure current while the light is running. That in turn can map to battery runtime and/or lumens. I wonder if any existing boards can do this, e.g. if they have adc pins connected to the relevant sense resistors. If not, it could be a cool feature in future boards.

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[โ€“] thefreeman 3 points 1 year ago* (last edited 1 year ago) (1 children)

if you have an emisar light and can disassemble it, then you can try soldering an airwire from the sense resistor to the button LED pad (sacrificing it for that) or a free ADC pin, but that's more difficult. If that cause problems with the current regulation, add a 10k resistor or the likes.
with a linear driver Iout=Iin so it's simple, with a boost driver Iin=(Vout x Iout)/(Vin x efficiency), thankfully Vin is already bein measured, Vout and efficiency need to be guesstimated.

[โ€“] solrize 1 points 1 year ago

Thanks, I do have a d4v2 but that's a level of modding that I wouldn't want to do for this. I s hoping enough capability might already be in the hardware, to make accessing it into a matter of programming. Maybe I'll just go with lux measurements.