Hi all!
My friend is terrified of the dark and wanted me to design a 'night light' for her with the following specifications:
Has to look pretty (rolls eyes)
After you turn it on, takes an hour or so to dim to dim linearly
It can't make any noise, such as a relay switching etc.
I have decided to have a tilt switch in it to there are no 'ugly' buttons on the outside of the thing. From there, I was going to create some sort of inverse ramp, which I am sure I can do with a current source and capacitor (will it really be ok over an hour?)
So I am hung up on the best design to do. (I have not really done this before). I thought there would be some sort of electrically-variable potentiometer that I could just have in series with the bulb, but I can't find anything like that. The other option looks like a SCR to control the phase, don't know how easy that would be to control. Or a TRIAC? Or there is something with BJT's or that ilk, since I have some experience there. Or maybe a high-power op-amp? As I said, I do not know.
So I would appreciate ideas as how best to implement this. Also perhaps ideas for things to scavenge, since I am sure it is something I can hack.
Thanks!
My friend is terrified of the dark and wanted me to design a 'night light' for her with the following specifications:
Has to look pretty (rolls eyes)
After you turn it on, takes an hour or so to dim to dim linearly
It can't make any noise, such as a relay switching etc.
I have decided to have a tilt switch in it to there are no 'ugly' buttons on the outside of the thing. From there, I was going to create some sort of inverse ramp, which I am sure I can do with a current source and capacitor (will it really be ok over an hour?)
So I am hung up on the best design to do. (I have not really done this before). I thought there would be some sort of electrically-variable potentiometer that I could just have in series with the bulb, but I can't find anything like that. The other option looks like a SCR to control the phase, don't know how easy that would be to control. Or a TRIAC? Or there is something with BJT's or that ilk, since I have some experience there. Or maybe a high-power op-amp? As I said, I do not know.
So I would appreciate ideas as how best to implement this. Also perhaps ideas for things to scavenge, since I am sure it is something I can hack.
Thanks!