EASYPIC4 Board Giveaway

[rmteo]

....Should the intensity change with each blink, ie each LED will need to blink 200 times to go through the full ramp up/ramp down?

This is a very good contest idea. Thank you!! (did I mention I love puzzles?)

How is the puzzle solving coming along? Getting close yet?

[cncmachineguy]

How is the puzzle solving coming along? Getting close yet?

The puzzle is coming along fine, I have it on a slow simmer.

Right now I am trying to decide on min and max frequencies. I am thinking .5 to 1000 Hz. But clearly 1K will look just full on, so I may go with 500hZ. Anything less then .5hZ will just be painful to watch.

Also trying to work out resolution for the frequency. Seems like it should not be linear with the pot adjust.

[rmteo]

Some pointers to take note of:

1. The variable/controllable blink rate should range from about 0.5Hz to no more than 8Hz - anything faster will appear as a flicker, which you do not want.

2. As the LED goes from full OFF to full ON and back to full OFF, its brightness has to be varied using some kind pulse modulation such as PWM or MIBAM. The frequency of this modulation has to be high enough that there is no flickering as the LEDs pulsate. Refer to the video and especially the drawing posted previously.

In essence, each of the LEDs is being driven by 2 modulated signals at the same time. A low frequency one from 0.5-8Hz which is the blink rate and a higher frequency one that controls the 0-100-0% percent brightness ramp which gives the LEDs a pulsating effect - instead of just going OFF-ON-OFF.

Hint: Think FM.

[cncmachineguy]

Thanks for the more refined parameters. This should help us all. It at least helps me to not have to decide on the spread.

The hint is very nice, thank you. I guess my solution is that, but haven't thought about FM since college. As soon as I could get away from analog I did. Guess thats why I am a machinists. LOL

[rmteo]

I hope I have not confused you (or anyone else) with these explanations. Trying to put the concept into layman's terms is lot trickier than I thought. In technical terms the objective is:

To create 4 independently controllable, low frequency (0.5-8Hz) channels of analog signals (triangle waveform in this case) using digital modulation (such as PWM) with the LED's acting as a low-pass filter.

Now that sounds a lot easier to do, doesn't it?

[cncmachineguy]

Well actually I thought it was fine before.

[rmteo]

Bert, have you made progress? Looks like no one else (besides Walter and yourself) has a solution for this contest. Do you (Walter, or anyone else) feel that perhaps it is too difficult and the contest should be changed to something simpler?

[larryvc]

Anything less then .5hZ will just be painful to watch.

I might fall asleep watching at that rate. Working on ideas.

Hi rmteo.