EASYPIC4 Board Giveaway

[rmteo]

I have one of these that I no longer need (no GLCD). We can do another contest similar to the last one.

Walter, do you want to administer this one as well?

[rmteo]

The objective of the contest is pretty simple - to pulse/blink a minimum 4 LEDs (more is better) at independent, variable rates using any PIC of your choice. The actual blink rate is not important, as long as it is visually discernible. Also, the method to adjust the blink rate is unimportant - you can use POTs on ADC channels or whatever method you want.

Sounds easy? There's a small catch though - each LED must ramp-up and ramp-down in brightness from 0 to 100% and NOT just toggle hard-on and hard-off.

[cncmachineguy]

RMTEO, Hats off to you this is very generous.

Now I realize this new contest hasn't been approved yet, but I have 1 question. 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?)

[rmteo]

The blink rate/frequency has to be adjustable for each of the LEDs. For every blink, each LED should ramp from 0-100-0% brightness. Perhaps this video of 2 LEDs will give you a better idea (note that the blink rate is different for each LED).

[mackrackit]

Blinky ideas??
http://www.picbasic.co.uk/forum/show...47&pagenumber=

[rmteo]

Blinky ideas??
http://www.picbasic.co.uk/forum/show...47&pagenumber=

Unfortunately, none of those ideas will qualify - they are just simple ON/OFF blinkies. Take a look at the attached drawing. The horizontal axis is time and represents the blink rate. The vertical axis is the LED brightness. The post that you linked to is like the upper trace. What I am looking for (as in the video above) is shown in the lower trace.

Also, the blink rate (or period) needs to be adjustable by some method of your choice. A minimum of 4 LEDs/channels are required. The blink rate of each LED needs to be adjustable independently and should not affect any of the other channels.

[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.

[larryvc]

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

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

Hi rmteo.

[ScaleRobotics]

Walter, do you want to administer this one as well?

Seems like you are doing a fine job rmteo, and great challenge! If you still want help, let me know, I would be happy to.

Is Mibam allowed, or is that cheating? http://www.picbasic.co.uk/forum/cont...-Modulation%29 .

[rmteo]

Thanks for your offer. I will handle it for now. You could move this to a more appropriate forum if you think it should be.

Any technique (including MIBAM) is good.

[rmteo]

Feel free to ask questions or to have any points clarified.

[rmteo]

...Is Mibam allowed, or is that cheating? http://www.picbasic.co.uk/forum/cont...-Modulation%29 .

Were you able to do it using MIBAM?

[cncmachineguy]

Is this a first valid answer wins contest, or post and vote.

[rmteo]

Is this a first valid answer wins contest, or post and vote.

The person to come up with a working solution first wins - NO voting this time. The end date will be 30th April, 2011.

You want to start posting about your potential solution as early as possible as it may affect the final outcome. Good luck and have fun!!!

[ScaleRobotics]

Were you able to do it using MIBAM?

Thanks rmteo. My question was more to hint at a possible solution for others, and to get a scope of the rules. You have laid out two nice possible paths to get it done.