- Wed Mar 03, 2010 2:10 am #95218
I found an article on instructables and it gave me an idea. is it possible to hook a rotary potentiometer up to this circuit without adding a micro controller and not over powering anything? Thanks.
Liencouer wrote:There's always the variable PWM 555 circuit somewhere... this looks about right...Perfect!... for now... lol.
MichaelN wrote:If it's only a low current, you could always have an adjustable constant-current circuit. If you've got enough voltage "overhead" you can use a 3-terminal voltage regulator as a constant current source. Otherwise, there are plently of other simple circuits that would do the trick.Hmm interesting. seems this would be more for an RGB LED project... which is where this project will probably end up.
lyndon wrote:If you use a linear PWM or current control, you will find that very small current changes near the bottom will cause huge apparent brightness changes and vice versa near the top of range.thanks I didn't know that.
waltr wrote:MichaelN's suggestion will work. Look up how to use an LM317 as an adjustable current source in the data sheet or in an app note.Your right. It looks like it might work a little better. Not sure which setup im going to use yet but I ordered some parts to test the original circuit and ill go from there.
Silent77 wrote:How would you modify the above to work with this... http://www.sparkfun.com/commerce/produc ... cts_id=678