stuben

Hello,

I'm looking for ideas to solve a problem.

I am making a framed navigational chart (map) to hang on the wall. I am putting tiny led lights where all of the navigation buoys are. Red lights, green lights, etc.

My problem is each light (sometimes there are 20 or more lights per chart) has its very own unique blinking pattern. An example of a light flash would be one 2sec flash followed by 2 1sec flashes with a 4sec delay.

Can anyone recommend an inexpensive device/controller that can accomplish this task. My budget would be up to $100 if something like this even exists.

hackableFM

Finally one I can answer.

I just started playing with PIC Microcontrollers a week or two ago, Already I have learned enough to use a 16F877 uC which would do everything you need.

It's quite difficult getting your head around it at first but given a bit of time you'd be able to use a microcontroller to do what you need.

hackableFM.

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When God was handing out the brains, I thought he said trains, so I asked for a small, slow one!

eblc1388

Your design can be done easily using a microcontroller(PIC or AVR) with sufficient I/O pins, at minimal cost. The cost of a microcontroller is a few dollars and a +5V regulated supply is under $10.

Everyone of the LED On/Off pattern is stored inside a lookup table in the microcontroller memory and at every fixed time interval(1 second, 0.5 or 0.2 second...)l the microcontroller checks up on the tables to see if there is any change need to make to all the LEDs.

If all LEDs have different "periods", here period means the total time that pattern for one LED starts all over again, then one would need up to 20 lookup tables. For example, one LED repeats every 9.5s but another repeats every 7.2 second...etc...

To reduce the total number of lookup tables, it is possible to stuff 8 LED patterns into one memory word. Therefore it makes sense to have more than one pattern that have a fixed repeated interval as then a single lookup table is needed. Please note the difference between pattern and total period. The pattern can be different but the period can be the same.

You will need to draw on a single time line chart of all the LEDs with shortest desire timing interval where changes are happening. Remember, all LEDs On/Off states should be know at a given time on the chart.

Does this make any sense to you?

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L.Chung

stuben

Thank you,

it does make sense, I understand what i need to do, the problem is I have no experience with programming microcontrollers.

Besides the microcontroller, what additional hardware and software will I need to configure the controller to drive the lights for my application.
Is a 16F877 ideal for my sitation or is there a microprocessor that would be better for my situation.


thanks!

HarveyH42

Will all of the same color, have the same pattern? Also, how accurate does this need to be? Actual navigation or wall decoration?

stuben

same colors will have different patterns. Accuracy isn't critical since it is just a wall decoration, but I would like to at least capture the "spirit" of each lights unique blinking pattern.

HarveyH42

I was just wondering how many actual patterns you might need, and how much 'give' there was in your idea. There was a lighthouse project last summer on this forum, with a similar flash sequence goal. Believe he went with a 4017 decade counter and diodes to tap along the outputs. Might be worth a search, if you want to avoid a microcontroller, and can settle for just a few patterns. Each pattern would require a 4017 (cheap and common part).