Dimmer Question

Juts a quick question on the way the dimmer logic works:

When I turn on the lights in my car, the player dims immediately. However, when switching them off, the player takes a couple of seconds to react. Why would the dimmer need a different time to witch itself on, than off????

Henno
mk2 6 nr 6

When I turn on the lights in my car, the player dims immediately. However, when switching them off, the player takes a couple of seconds to react. Why would the dimmer need a different time to witch itself on, than off????

This bothered us too when we first implemented that feature. The answer is, that many cars don't just switch the lights on and off in one go: they fade between. Moreover, they don't fade by smoothly ramping the voltage from 0 to 12V: they start with a few narrow spikes of 12V, then make the spikes wider and wider, until eventually the spikes "merge" and it stays at 12V.

For an analogue component like a lamp, this is an absolutely fine way to behave (the switching is very fast). For a digital component trying to sample the line, it's a complete nightmare.

We fixed the problem by making the empeg wait for the line to be stable for a while -- so we can distinguish the line "really" going up or down, from the line being "flickered" up and down. This does involve a short delay, though, which you've noticed.

Peter

the empeg wait[s] for the line to be stable for a while -- so we can distinguish the line "really" going up or down, from the line being "flickered" up and down.

Yep, I can see the need to so so, but why would it have to wait when its dims (when the lights are switched on) and reacts immediately when the lights are turned off?

Or is it may be caused by my car that gradually builds up voltage on the dimmer line when the lights needs to be dimmed, and immediately dropping voltage when dimming is no longer required?

BTW: It's a BMW

Henno
mk2 6 nr 6

Wow, it would actually be cooler to let it flicker the empeg screen. I picture it like a noir movie effect, you switch headlights on or off, and the empeg flickers like a old neon tube...

Calvin