Random ON/OFF Timer Circuit

Hello All

I was wondering if anyone can help with or knows where I can find a random ON/OFF timer circuit that will switch a 6-12v DC relay ON between a random period of say 5 to 20secs and then turn OFF for another random period of say 5 to 15secs.

I'm building an outdoor device and I'm trying to simulate random movement.

Any help will be greatly appreciated.

Regards Tom McMurtrie

Reply to
tom
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That is correct, the cycle would continue to repeat.

Regards Tom

Reply to
tom

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So, you want it to turn ON for a random interval of not shorter than 5
and not longer than 20 seconds, and then at the end of the ON period
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Reply to
John Fields

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Seems like you only need one.  I\'m working up a solution with an 8 bit
PRSG feeding the broadside load of an 8 bit down-counter.  When the
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Reply to
John Fields

Pending a more elegant solution, you could adapt this circuit I designed for my 'Surf Synthesiser' many years ago:

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That delivers an output duration (simulating gaps between successive breakers) chosen randomly from 10 preset values from roughly 9s to 20s (determined by the resistor choices). It sounds like you need TWO such

4017 sections, one for ON and one for OFF.

But if I was tackling your task from cold, I'd probably start by playing with a couple of pseudo-random generators made from shift registers.

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Terry Pinnell
Hobbyist, West Sussex, UK
Reply to
Terry Pinnell

Neat! Look forward to seeing it.

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Terry Pinnell
Hobbyist, West Sussex, UK
Reply to
Terry Pinnell

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OK.  

I\'ve posted a schematic for you at alt.binaries.schematics.electronic
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Reply to
John Fields

Hi John,

Thanks for your help along with the other guy's replies too.

I have had a browse through alt.binaries.schematics.electronic under "Random ON/OFF....." but I haven't managed to see a link to the schematic.

Would it be appropriate to forward it to me direct at tmcmurtrie@@keystone.otago.ac.nz (remove the 2nd @)

Thanks Tom

Reply to
tom

Nice stuff! I'm hoping the OP will ask you for some narrative, as it would save me a lot of time .

But, hey, that's arguably even more complex than my 4017 suggestion!

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Terry Pinnell
Hobbyist, West Sussex, UK
Reply to
Terry Pinnell

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You\'re in luck!  He did, so I posted the circuit description and a
corrected schematic (sigh...) to abse.
Reply to
John Fields

Thanks. Looks good. Only wish I had time to either simulate or breadboard it .

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Terry Pinnell
Hobbyist, West Sussex, UK
Reply to
Terry Pinnell

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