I want to have anywhere between 6=10 LED's in a row and the ability to switch between one LED and the one next to it. I would also like to transition between one LED and the other. So that as one LED fades out the next in the series begins fade in. I must have the ability to have only the selected led lit up when it is at full power ie. I don't want all the leds to light up as I go down the line of the array. I was thinking of using a multiple position rotary switch, but being a relative n00b I was not sure if that would allow transition or simply switch be tween each led. Any help is greatley appreciated.:rofl: :rofl: :rofl:
I hestitated commenting before since I'm not sure what you're attempting to do. If you simply want to turn on LEDs in series and leave the last LED On as you switch the next LED on, a "make before break" switch will certainly do the job. You could even wire all the grounds together and use a single pole switch.
Clarification I realize I may not have been clear earlier so let me try to clarify a little. I simply want to be able to switch between a row of leds without simply having one turn off and the next one turn on but rather a fade between one and the next in the series.
I think I'm as n00bish as you, but can't you just use an inductor to create the fading effect? Or maybe add in a capacitor depending on how much energy you need. Check out the thread here as well. If you look at the ICs... the output 0-9 can be used to power separate LEDs, if you add an inductor to each one (or maybe an inductor and capacitor) you may be able to reach the fading effect. There's a related article at Rabid Hardware, I'm sure adding part of that on to each LED would work too... Time to brush up on my electronics skills! -Dave
Re: Clarification Is the intent just to manually switch the LEDs or are they indicating a "state", i.e. the shift in LEDs symbolizes a temp, power or other level and are automatically activated? As far as the fade effect (and they are much more knowledgeable people around here than me) you could use the "previous" LED to drain a charged capacitor while the "next" LED is powered by a charging capacitor. The "previous" LED would then fade out as the "next" LED fades in. That may be the simpliest design. WIthout compleetly designing the circuit it would seem if you used a multiposition switch apply power to capacitors in series with LEDS, it would achieve the fade effect you're looking for. From reading the Rabbit Hardware article cited above, it appears that some LEDs do not function well with variable power and will not fade like you want even if the circuit is built correctly. You may want to try various LEDs when testing.
Intentions My plan is to use this circuit with a fanbus so that as the fans a cranked up I get a nice change of colored leds from blues through the spectrum to reds. So ideally if I could controll the ability to switch each led on and off by some sort of chip that requlated the power being sent to the fans. It has become immaculatley clear how n00bish my electronics knowledge is.:rofl:
Do you have a design you're following or modifying? It would help to see how you're controlling the fans -- PWM/rheostat, logic circuit/multi-position switch, etc. I'm guessing you plan to use a rotary or other type multiposition switch for the various voltages based on earlier comments. If so you could power the off the same switch, e.g. use a double pole where one pole provides voltage to the fan(s) and the other power to the LEDs as discussed above. Hope this helps.
It seems to me that if you used a LM3914 with the outputs in series with the LEDs and capacitors, you could acheive that effect. That IC is now my second favorite after the 555.
