I forgot to add: do not attempt to just calculate duty cycle and try it immidiately. Start with lowest duty cycle and increment it until you see the filament getting hot. My arduino sketch has a "soft start", it increments duty cycle by 1 every second until it reaches limit. I didn't test if you can start a cold filament by driving full 4% cycle, I recommend doing a soft start - maybe 10 seconds is too much (in reality, we could increment with every pulse, I think). When I implement that in an actual clock I'll do a ~0,5s soft start.
W dniu piątek, 17 marca 2017 13:02:13 UTC+1 użytkownik ten kowal napisał: > > > Hi, if anyone is interested, here are the results: yes, you can PWM IV-6 > filament directly from 5V. I tweaked a bit arduino analogWrite() by setting > prescaler to 1 (thus changing PWM frequency from ~4kHz to 32,5kHz) and set > PWM to really low duty cycle (max 10/256, which is around 4%). I didn't > feed the filament directly from pin, I made a simple MOSFET switch - it has > low RDSon, so we can simplify it to having 5V directly on filament. > > Tests are positive, on 10/256 the filament is visibly hot (but far from > being overdriven and burning), and stops being visible at 8/256. Applying > voltage 25V higher than cathode on all anodes+grid correctly lights up all > of them, they look identical to directly heated filament one. > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/c11fdc11-77e2-482b-917a-8a30a5055f62%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
