0
\$\begingroup\$

I would like to create navigation light sequences on old admiralty map of my local area. There are lighthouses and channel markers in area with mix of flashing and times. The single flashes I can use a bought LED flashing kit but its the pulse flashes every x seconds that I'm stuck on e.g. LED flashing twice every 10 seconds. Not every 5 s but at 1 Hz and every 10 seconds so LED flash first sec, flash second sec then off for 8 seconds before repeating. From what I've seen on the map there 2 flashes or 5 flashes in times given. So that looks like Fl(2) R 6s, "Flash twice Red every 6 seconds".

I've looked through forums and can't find a direct answer to above, if you've come across anything like this could you help. I'm ok on hardware side of things but programming wouldn't be my strongest suit. Thinking about it I could only come up with two options:

  1. A mircocontroller able to pulse the LED's at 1hzish and able to control power on/off for the associated times.
  2. A asymmetrical timer that would control power to a LED Flashing kit so the power on would be shorter then power off and this would repeat periodically.

Any help would be appreciated.

\$\endgroup\$
  • 1
    \$\begingroup\$ Your first example is actually flash for 1 second, off for one second, flash again for one second and off for 7 seconds. \$\endgroup\$ – Peter Smith Feb 20 at 16:51
  • \$\begingroup\$ Are you looking for each one to be independent, or to control them all with a single controller?. \$\endgroup\$ – Phil G Feb 20 at 17:56
  • \$\begingroup\$ Looking to control them with single controller. But they will all have different and delay times. I've been looking through forums see if there is any similar problems, haven't come across one yet. Ones I've seen all show multiple LED's in a sequence, I would like each one working independently but from single controller. Thanks A \$\endgroup\$ – A. English Feb 21 at 14:55
2
\$\begingroup\$

I would recommend a micro-controller solution to this as it gives you timing accuracy and easy reconfiguration as well as a chance to learn something new without too much effort. Any analog timer solution such as the famous 555 timer requires several resistors (some of which would need to be adjustable) and capacitors as well as designing some sort of prototype board layout and soldering it all up. Then you have to repeat it for each lamp.

Something like the Arduino board would be a good start and there are thousands of articles and code examples available.

On a side note: you could simplify your timing explanation by using a timing diagram. These are understandable in any language.

  1  2  3  4  5  6  7  8  9  10 11 s
   __                            __
__|  |__________________________|  |____ Light A
   __    __                      __    _
__|  |__|  |____________________|  |__|  Light B

Or, for short flashes ...
   1   2   3  ...            ... 11  12
   _   _                         _   _
__| |_| |_______________________| |_| |_ Light C

Figure 1. Beacon timing diagram.

Not every 5 s but at 1 Hz and every 10 seconds ...

You are confusing pulse-width and frequency. One pulse every 10 s is 0.1 Hz (cycles per second) no matter how wide the pulse is. An engineer might describe it as 0.1 Hz with 10% duty cycle. Your more complex patterns are best described with the timing diagram.

One thought if you are using a micro-controller is that you wouldn't want all the lights to blink at the same time as shown in my timing diagram as it wouldn't occur in real life. You would need to offset them slightly and maybe put a slight error into the overall cycle of some of the lamps. e.g. 10 s and 10.1 s.

schematic

simulate this circuit – Schematic created using CircuitLab

Figure 2. The whole schematic for an Arduino style controller.

\$\endgroup\$
  • \$\begingroup\$ Thanks Transistor, ya going to try this when i get home. Hopefully won't be to frustrating!!! \$\endgroup\$ – A. English Feb 21 at 9:35
  • \$\begingroup\$ I've assumed that you're using 10 to 20 mA LEDs. There is a limit on how much each micro-controller can handle per pin and per whole chip so check each of those. If you need higher current we'll have to complicate things a little. \$\endgroup\$ – Transistor Feb 21 at 9:51
  • \$\begingroup\$ I'm not sure on number of LED's yet, but they will be 10-20mA type. Going to have to lay them out on map. Because of scale some are quite close so might lose some to clean it up. I was looking online about Arduino, from what i could gather it can handle 8 LED's per controller no problems which should be enough for me. I only really need it for the multiple flashing marks. Thanks A. \$\endgroup\$ – A. English Feb 21 at 10:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.