Comment on Digital buffer works for a bit, then stops, turning it off for an hour resets it to working again
litchralee@sh.itjust.works 5 weeks ago(sorry for the long delay)
From your description, I’m wondering if the internal pull-up from the bike computer might actually be an active output, and that the open-drain buffer is causing the bike computer to give up sourcing that pull-up voltage. That is to say, if a larger-than-expected current is drawn from the bike computer, it might trigger a protection mechanism to avoid damage to its output circuitry.
To that end, I would imagine that either: 1) an inline resistor to limit drain current, 2) a push-pull buffer, or 3) both, would help rectify the issue.
My suspicion is based purely on the fact that getting stuck low for an open-drain device could be an issue “upstream”. If it were stuck high, I wouldn’t normally suspect this path.
avidamoeba@lemmy.ca 5 weeks ago
No prob whatsoever. I appreciate your time.
As for the computer, I have no idea and I’m not skilled enough to check. I ordered some push-pull quad channel buffers from TI and Nexperia, SOIC breakout board and decoupling caps. Unfortunately I made it work using a Trinket M0 with a trivial CircuitPython program. Already tested it on a bike ride and just sitting powered on over 24 hours. No failure so far, so I conformally coated it and installed it. The fly was killed with a bazooka. 😂 And so I think I’m gonna keep it like that and will revisit the new buffer ICs I bought if it fails again, or if I need to build another adapter. Thank you for your help!
litchralee@sh.itjust.works 5 weeks ago
BTW, you might consider posting about your finished results at !micromobility@lemmy.world . We enjoy all things bicycle-related there, especially when it’s solving a unique problem or solving it in unique ways.