flashing light sequencing control

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17 February 2011 at 12:26 #29883
Kimosubby Shipyards
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@kimosubbyshipyards
I’ve accepted a project to make a set of buoys for training and thought to complete the set by adding to each its required light characteristics.

Simple LED flashing could be used, but I’m wanting timed loops of flashes, example being the S cardinal buoy, quick flashes (6) plus one long flash every 15 seconds.

I’m looking at using the “555 timer circuit” and variations of it, astable, bistable and mono stable variations. Has anyone already done this and be willing to pass on their secrets? I’ve info from Wikipedia and Doctronics.

I’m open to all suggestions.

The buoys, when made will be about 75mm (3″) size and will cover all and possibly any found in British waters. I’ve not started yet. I’ve seen on a US web-site models (USA waters have reversed buoyage to UK, they are zone B, We are zone A) but these are quite expensive! I want to do this (at present) for free.

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17 February 2011 at 12:26 #5112
Kimosubby Shipyards
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@kimosubbyshipyards
to generate timed flash sequences etc
17 February 2011 at 23:17 #29886
Dave Milbourn
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@davemilbourn48782
I think you need to kidnap the nearest PIC programming person, Kim. There must be some very clever dudes on that little island of yours…………and no – I don’t !

DM
21 February 2011 at 05:58 #29899
PMK
Participant
@pmk
I’m with DM on this one. I too would opt for the PIC route for several reasons – not least that the exterior (or on-board) crystal oscillator of the PIC would yield much more precise timing of the flashing sequences.

The use of a 555 timer could well be used as the main timing oscillator, but then you would probably need a handful of separate counter and/or logic chips in order to obtain the particular flashing sequences. By which time the entire circuit may be somewhat cumbersome and you might have trouble trying to shoehorn the whole caboodle inside your designated 3-inch buoy.

A single 8-pin PIC controller, on the other hand, would do the job easily, and would fit on an altogether much smaller circuit board. The downside to using a PIC is that you would need the means to stuff the relevent HEX code into the PIC. If you are without the means of programming the PIC yourself, then the secret is to knock twice and ask nicely.

As an aside, you probably would not need a separate PIC for each sequence of flashes. In other words, the same PIC could store a whole host of separate sequences – each selectable by a simple press of a wee on-board tactile switch.

Edited By PMK on 21/02/2011 06:09:38
21 February 2011 at 07:54 #29900
Kimosubby Shipyards
Participant
@kimosubbyshipyards
Dave and PMK,

I hear what you are saying, I’ll still try the 555 as I now have them and at 18p each not too much waste if no good. In reality, there’s only one flashing group that’s the problem, all other flash sequences are simple and a lot are just the right Hz flashing LEd for control.

We do have a club member who can prog PIC, he did his dredger with one to control the grab and hoist movements. I’ll butter his toast and see where that gets me.

I’ll keep you up to date with any progress, Kimosubby.
21 February 2011 at 08:01 #29901
Dave Milbourn
Participant
@davemilbourn48782
Don’t forget this little gizmo http://www.action-electronics.co.uk/pdfs/P73.pdf

If the sequence is just a plain single or double flash at a fixed rate then it’ll save you mucking about with 555 chips and veroboard.

Suit yourself.

DM
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