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microsoft / jacdac

Device and service catalogs for Jacdac.
https://aka.ms/jacdac
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Power module USB power tickle? #535

Open jamesadevine opened 3 years ago

jamesadevine commented 3 years ago

As we learned earlier, most USB power packs turn off power provision when there is a negligible power draw. We might need another padauk to sink a load of current periodically...

mmoskal commented 3 years ago

this can probably be done without Padauk, with some RC-delay circuit or some such. There's a simple one here: https://www.sotabeams.co.uk/content/ELI.pdf (most others I found were using 555 timers)

jamesadevine commented 3 years ago

Should all brains also have this circuit (or similar?)

jamesadevine commented 3 years ago

CC @GakureKaruri

mmoskal commented 3 years ago

If you have brain then maybe it’s better to control the load from the MCU? That way you can adjust the power draw (duty cycle).

GakureKaruri commented 3 years ago

this can probably be done without Padauk, with some RC-delay circuit or some such. There's a simple one here: https://www.sotabeams.co.uk/content/ELI.pdf (most others I found were using 555 timers)

Since the power would always be on this would drain the battery fast. 555 timers option would increase the module cost due to the passive components required. Duty cycle by the MCU would be the most preferably option as it requires 2 resistors and a mosfet.