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Programmable Solar Porch Light Circuit

Programmable Solar Porch Light Circuit

The post explains a porch light circuit with programmable timer controller which enables the connected LEDs to light up or shut off after some delay, as preferred by the user, thus it's not entirely dependent on the solar panel parameters. The idea was requested by "Unknown".

Technical Specifications

It'd be neat if you devised a circuit that could:

1. Detect Darkness
2. Wait an adjustable amount of time, say 1-3 hours
3. energize a light, or relay
4. Stay on for an adjustable amount of time 3-8 hrs

That'd be a huge improvement over typical solar porch lights, as they typically come on too early, and stay on too long.


The Design

Referring to the proposed solar outdoor light circuit diagram, we see a couple of IC 4060 timer stages interlinked together to form a set of sequential programmable timers.

During day time when the solar panel is active, the connected battery is allowed to charge through it, while the 4060 timers are held inactive due to the presence of the positive voltage from the panel to pin12 of the upper 4060 IC.

When darkness sets in, depending upon the selection of the zener diode between the solar panel positive and pin12 of the upper 4060 IC, the voltage is brought down to zero allowing pin12 to get a resetting zero logic via the connected 1M resistor.

Once this happens the upper IC 4060 begin counting and after a predetermined delay set by its pin9 capacitor and pin10 pot, its pin3 goes high.

The BC547 connected with this pin3 now activates all the connected LEDs illuminating them after the desired period of time has elapsed. The 1N4148 diode connected across this pin3 and pin11 of the upper 4060 freezes the IC counting process and latches the LEDs permanently ON.

However, in this situation, the lower BC547 also gets triggered and resets pin12 of the lower IC 4060 which in turn begins counting, and identically after a set period of time determined by its own pin9 capacitor and pin10 pot values switches ON its pin3.

This high from pin3 of the lower IC 4060 latches itself due to the presence of the 1N4148 diode across its pin3 and pin11, and it also grounds the base of the LED BC547 driver such that all LEDs shut off.

The entire solar porch light timer circuit now latches in this position until the next morning, when the rising positive voltage from the solar panel yet again resets the upper IC pin12 and the entire circuit. The circuit stays inactive until dark.

The cycle thus keeps repeating as explained above.

Single Adjustable Delay OFF Solar Timer Circuit

The above explained design can be simplified to obtain an adjustable delay switch OFF after the LEDs are switched ON in the evening.

Circuit Diagrams




About the Author

I am an electronic engineer (dipIETE ), hobbyist, inventor, schematic/PCB designer, manufacturer. I am also the founder of the website: https://www.homemade-circuits.com/, where I love sharing my innovative circuit ideas and tutorials. If you have any circuit related query, you may interact through comments, I'll be most happy to help!

13 thoughts on “Programmable Solar Porch Light Circuit”

  1. sir i made this circuit two to three times. I checked each and every point, but at first time relay get activated but after second third time relay not activated. I check test point. I get following observation.
    Data: Supply 12.39 volt, Using relay at LED
    1: I connect 1 led at pin 9 which blink with counting. at stops it continuous glow.
    2: At the end, pin 3 get voltage 10.36v
    3: At 10k left side 10.36v & right side 85.54mv
    4: At base of transistor 85.55mv
    5: Relay not activate.
    6: 2nd IC not counting, it gets freeze.

    Please help me i already made 3 pcb board but not successful.
    please check below link

    • Ashok, do not connect anything at pin9, 10,11 as it may disrupt the normal functioning of the ICs.

      connect LEd at pin14 or 15 03 13 of the IC, if it flashes will indicate the IC is counting.

      For confirming the operational sequence, connect LEDs in series with all the transistor base resistors.

      your statements are all contradicting

      First if you apply voltage at pin12 of IC1 it'll never start counting which in turn will keep the lower IC also frozen.

      you say that pin3 is showing 10V….that's impossible when pin12 is kept high.

      So there may be something critically wrong in your design….pin12 of the top IC must not get the 12V supply otherwise it'll never initiate.

    • SIR I GET THE PROBLEM SOLVE, ACTUALLY IC GET FAULTY. i replace 4060 then circuit works fine. but after some time because of my miss handling again ic have same problem. again i replace another new one now its work fine.
      Now my question is is there any procedure to avoid this parts fail? or how to check or purchase original parts.
      Are these parts are fragile?
      please help me for this so this project not goes to costly.

    • Ashok, if the supply voltage to the IC does not exceed 15V it is very unlikely to get faulty.

      buy ICs of reputed brands like ST, MIC, intersil etc. for getting genuine response.

  2. Sir as commented in above i already made this circuit 4 times but delay on gets failed because from red LED indicator voltage get supply to the base of transistor BC 547 ( marked in pic).

    • Ashok, that cannot happen because when switched ON the IC will reset and begin with a logic zero at its pin3, this zero logic will sink the LED voltage to ground level so that no voltage flows to pin11….and that's why the red LED would light up.

      for confirming you can remove the red and check…..

  3. Sir please check this image 4.bp.blogspot.com/-LWTCAHef9_I/VLjW36ME-vI/AAAAAAAAAKk/4Q59xls74T8/s1600/solar%2Bgarden%2Blight%2Bwith%2Btimer%2Bcircuit.png

  4. hi swagatam

    i need a circuit which will charge 12v 3ah battery during day on solar and automatically illuminate leds at no sun light. and it will off after 4 to 5 hrs. the purpose is to drive led strings for diwali decoration

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