Off Timer

Gotta' be something here that would work for you...

https://www.amazon.com/Best-Sellers-Electronics-Motion-Detectors/zgbs/electronics/11040971

https://www.mrbeams.com/motion-detector-lights

A one-shot timer relay should do it. Lots of mfrs.

See below:

I would start with this:

The low power dissipation of the LMC555 makes this a good choice for a battery operated device. The circuit is pretty simple.

The graph below shows what values of R_A and C to get the desired timing cycle. (R_B is zero in this case.)

Pages 8 and 9 of the datasheet have more details about the monostable operation of this part.

http://www.ti.com/lit/ds/symlink/lmc555.pdf

The 555 timer is one of the most enduring designs in electronics, circa 1972. Still used extensively today. Easy to use, well known, and tons of example circuits on-line.

https://en.wikipedia.org/wiki/555_timer_IC

If your trigger signal is a positive going pulse, add a CMOS inverter to the trigger input. You can drive your lights using a MOSFET as a solid-state relay on the output pin of the LMC555. Add a 10K gate-to-source resistor to discharge the gate charge at the end of the timing cycle. If you want to switch the high-side of the lights, a P-channel FET would be needed. If you can switch the power return of the lights, then a more common N-channel FET can be used.

Good luck with your quest !!

(blue . . . . NO! yellow !)

Here is a single-gate package with a low power inverter.

http://www.ti.com/lit/ds/symlink/sn74lvc1g14-q1.pdf

Digi-Key is a great place to buy electronic parts on-line. They have a USPS First Class shipping option of $4.99 for orders less than 13 oz. You will get it in just two or three days in most cases. Orders up to 8 PM central time get shipped (packaged and ready for pickup) that day !! Freaking incredible. I don't know how they do it. In my work capacity, I have ordered parts at 8:30 PM eastern, with overnight express shipping, and it was on the shipping dock at 10:00 AM the next day.

Digi-Key is awesome.

Make it adjustable with a potentiometer for R_A .

Thanks a million for the great guidance and suggestions,especially the low power 555.

I can make this work.

There is a penalty to be had from using the 555C over a 555. The 555C has a lower output drive 100mA than a 555 which can drive around 200mA. I have found this to be source of problems in an oscillator circuit to generate a HV for a meter tester.

If you team it with a ULN2001/2002/2003/2004 darlington driver with 500mA per output or parallel the 7 outputs to obtain 3500 or 4200ma peak.

You could just drive a relay from the 555 output

All we're doing is driving the gate of a MOSFET.

The output of the 555 only has to drive a tiny amount of gate capacitance and some pull-down resistance (10K or even 100k would work fine for a gate-to-source resistor to guarantee turn-off). I don't believe using bi-polar transistors would be an energy efficient method to switch lights or worse yet using a relay.

It is very easy to find a logic level MOSFET that can drive 5 A all night long. If you wanted to switch the high side, here is a P-channel FET from Diodes Inc. that has a V_DS of 25V and drain current rating of 7.3 Amps.

https://www.diodes.com/part/view/DMP2039UFDE4

If you can switch the return side of the power source, there are thousands of N-channel FETs to do the job.

Here is one in an easy-to-use TO-220 package.

ON Semiconductor FDP8874. It's $1.46 at Digi-Key.

With a gate to source voltage of 4.5 V (logic level), the R_DS(ON) is 6.6 milohm.

The V_DS is 30V and a maximum current rating of 114 Amps.

https://www.onsemi.com/pub/Collateral/FDP8874-D.PDF

Cheers !

Sorry, I would prefer a little Rory Gallagher and some Gabbiano Chianti Classico as I ponder...….

Or how about some Easy Cheese on a Ritz while listening to the Bay City Rollers?

(Although I remember it as Cheese Whiz)

I would start with an off-the-shelf electric timer on a relay base, Mildred, and add on to it whatever other circuitry you need. Under £30 all-up even allowing for post-war inflation. Dozens of suppliers...