Onboard 10K pullup for SWA input, allows for longer wiring to an external switch without risk of intermittent operation. Never reported as a problem - but hey, might as well beef up the design when possible.
I'd like to take this opportunity to report this as a problem for me. I've been riding around with my new DIY bike light system for a little over a week, and several times I've noticed the light turning on by itself. At first it was a mystery, but then I figured out why it was doing it.
I was playing with my Schmidt SON dynohub, and every time I made or broke a connection to it while the wheel was spinning, my light turned itself on. The light system is battery-powered and totally separate from the dynohub for now; I plan to use the dynohub to charge the batteries later. I have the batteries (12 AA NiMH) and the bFlex in a water bottle mounted on the underside of the downtube, just above the bottom bracket. All connections are securely soldered and insulated. The lights are mounted on the top of the front rack, and the switch is on the handlebars. Right now it's just the switch that came with the bFlex, connected by 5-6 feet of 24 guage stranded speaker-type wire.
I also notice the light turning on by itself if I touch any metal part of the bike and there's a bit of a static electric spark. It doesn't take much; sometimes it's small enough I don't notice it. I've also done some little tests with making small sparks from a battery; this usually turns the light on if I'm within a foot or 2 of the bike.
So, this is RF noise (energy) being picked up by my big antenna of a switch wire, and the bFlex interpreting it as a click, right? I don't have superlock enabled (though I probably will want it) and I have noticed sometimes the sparks making the light change modes (again acting as a click) when it's already on. So far it hasn't happened while I'm riding, and only twice has it turned on while the bike was parked and I was away for awhile, once for several hours and it drained my battery.
How do I fix this? A shorter switch wire isn't an option; should I use a little capacitor across the switch terminals at the bFlex? What's the 10k pullup you have on the V2? A resistor?
You may want to do some experimenting to see if you can make a bFlex pick up RF noise from sparks with a long switch wire. It shouldn't be hard. Let me know!
Alex
