Fading LED without PWM?
Greetings all, after some searching I can't seem the find any methods for Fading LED's in and out without using PWM. I am working on some lighting for a movie prop, and the PWM is causing noticeable flicker on camera (in the dimmer ranges). We are driving some powerful LEDs through a luxdrive.com buckpuck. The driver has a control lead that we can manually control with a 5k Pot. Any help would be greatly appreciated.
Thank you very much.
Thank you very much.
Comments
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·"If you build it, they will come."
Somebody more knowlegeable than me will have to verify this.
You could also use the digital potentiometer to control the LED. However, the digital pot that we have is a 10 KΩ; but you could control it with a microcontroller enabling you to program the LED. There is an example of using the AD5220 digital pot in What's A Microcontroller? text [noparse][[/noparse]chapter 9]. Here is a link for your review.
What's A Microcontroller? Text:
http://www.parallax.com/Portals/0/Downloads/docs/books/edu/Wamv2_2.pdf
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Respectfully,
Joshua Donelson
www.parallax.com
https://shop.maxim-ic.com/storefront/searchsample.do?menuitem=Sample&event=SampleSearchLoad
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There is no problem that can't be solved with a suitable amount of explosives!
EOD Memorial
http://ww1.microchip.com/downloads/en/DeviceDoc/22060b.pdf
They seem pretty cool, they use serial to increment or decrement the wiper. And from what I can tell you can read the wipers location and set a specific location. But I am trying to figure out how I would wire it up and send commands to it. So that when they arrive I can dive right in and see if it is my flicker solution. So basicly I am asking if some of you fine folks could take a look at the datasheet and give me a nudge in the right direction. I am gettting confused with the memory location and errcmd bit settings.
Wow, that's awesome! So what if I want to use a ten turn pot????
http://forums.parallax.com/showthread.php?p=875428
Did you see this thread? By applying a PWM command to the input of the RC network the capacitor gets charged to a voltage with 255 steps. or 8 bit. (At least with a BS2 it does...) Then the OPamp buffers that to provide current to the transistor which if you pick correctly could power your high power LED's. Maybe a darlington pair?
This code should then fade the LED in and out with no flicker...
FOR counter = lowlevel TO highlevel
PWM pin, counter, time
NEXT
FOR counter = highlevel TO lowlevel
PWM pin, counter, time
NEXT
Time needs to be established by the RC network as in the analog and digital parallax book as:
4 * R * C = time in milliseconds.
And the lowlevel needs to be put right where the LED starts to come on.
and Highlevel's max should be 255
Post Edited (Campeck) : 1/29/2010 11:44:45 PM GMT