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Computer room keyboard light

   I want a dimmable low-wattage led lamp to mount to my computer desk shelf. It will sit above the keyboard, shining diffuse light down but not directly at me.
   I could mount it underneath with screws, or have it sit on the shelf above, looking over it.
   It'll be powered by 120V 60Hz, so no batteries required.

   I have two design problems that I need to solve before I start.

   First, I need a diffuse light source that will light up my entire keyboard without blinding me with a direct view. This should be a warm white rather than something bluish or cold, since I don't want to lose my night vision. (I watch movies and do graphics on the computer at night.)
   I haven't been able to think of anything that will fit back far and high enough that my slouched posture won't cause a problem. I thought of an opaque diffuser that the light would shine up into, but the geometry seems a little tight.

   Second, I would like recommendations for the dimmer control. I want to dim the light right down to nothing, and switch it off, easily and quickly for when I'm stumbling off to bed. It needs to be a bit sturdy to handle my fumble-fingered ways, and quick to find.

   I appreciate any suggestions anyone can come up with, and I'll be glad to gab on more about what I want if you have any questions.

   The shelf is 28" or more from my eyes when seated at the desk, and about 30 degrees of it is currently blind to me at maximum slouchiness. It sits 6.25" above the desk, and I can easily spare 4" of clearance under it; the only other thing that has to fit there is the keyboard itself with a little wiggle room.

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Goodhart6 years ago

First, I need a diffuse light source that will light up my entire keyboard without blinding me with a direct view. This should be a warm white rather than something bluish or cold, since I don't want to lose my night vision. (I watch movies and do graphics on the computer at night.)



 Ok, well red LEDs would work for this,  even the very bright ones.

Second, I would like recommendations for the dimmer control. I want to dim the light right down to nothing, and switch it off, easily and quickly for when I'm stumbling off to bed. It needs to be a bit sturdy to handle my fumble-fingered ways, and quick to find.

Since you are using LEDs, that computes to DC voltage, and so any potentiometer will do, but one caveat:  the LED's operate under a specific voltage so that they will "turn off" before the potentiometer reaches the lowest position.   SOME LED's are either on or off, and not dimmable,  so you would have to create some sort of shutter or light limiting system in between them and your work, to adjust the light output.



Trelligan (author)  Goodhart6 years ago
I'd rather have a warm white rather than red, for general usability. I might have to read something and not want to get up and turn on the room light.

My main point about the dimmer was that I wanted something easy to operate. I can buy pots in rotary or linear formats; they don't even have to meet the power requirements since I could womp up a simple PWM circuit from a 555 timer.
What I need is an idea for something that is easy to reach for, simple to operate and with an off function.

I looked into some of the capacitive touch devices and they seem to be out of my price range for now.
I looked into some of the capacitive touch devices and they seem to be out of my price range for now.

Have you looked into building one? If you isolate it from the mains with a transformer, it shouldn't be too hard to build.  They normally use a flip flop to change states when there is input, and when you touch the metal you act like an antenna and should activate the "switch".
Trelligan (author)  Goodhart6 years ago
It's my understanding that capacitive touch devices (that needs an acronym!) are difficult to design, and that's why companies are designing chips that auto-seek to compensate for noise level and such.
If you know where an Instructable (or equivalent) for such a circuit exists, please let me know.
I've requested prototype packages from a manufacturer, but I'm not gonna hold my breath. I was too honest when I filled out the forms . . .
Well, you have a few options:
There "are" converters on the market like those at  NextTag
etc.

Or there are diagrams such as at  Circuits !

Which, with a step down transformer and a relay could work, OR

this one for 120 VAC

PAIA dot COM  has one also.

And a PDF, that has further info on the subject:
Trelligan (author)  Goodhart6 years ago
Thanks for the links! I'll be trying out some of these on the breadboard next weekend.
Your point about wanting to read something makes sense, but any white light will ruin your night vision. That's why "night flashlights" use a red filter.

If you're already willing to give up your night vision in order to read something, then you could use a "checkerboard" array of red LED's and white LED's. Don't worry about the dimmer, just a three-position switch -- wire the reds one way and the whites the other.
Trelligan (author)  kelseymh6 years ago
Whoops, forgot to say: Great ides with the red/white LEDs and the switch.
This is the way I'm tending at the moment, I could set-and-forget the brightness with a trim pot or something, and use the switch to operate.
Trelligan (author)  kelseymh6 years ago
Perhaps I misspoke, I suppose I didn't really mean night vision. I'm already looking at a monitor with (potentially) quite a bit of white of its own.
What I don't want is something that glares like my current floor lamp or lights up the whole room like my overhead light. I want to watch the movie without seeing too much of the room.
I know that I'll 'ruin my eyes' if I try to watch the monitor in total darkness, but in this room the monitor itself is light enough for that - except when I'm trying to see my keyboard.
crapflinger6 years ago
why not just get a backlit keyboard
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