I have a solar light with motion detection that works fine outside. I'd like to know if I can use it inside as well. I want to place it on the windowsill of my clerestory window so that it charges during the day from sunlight. And at night I want it to turn on when it detects motion.

solar light

But what's not working is that the photoresistor, or whatever, is not detecting that the room lights are on at night presumably due to its location high on the ceiling. And so motion at night when the lights are on triggers the light on.

Is there a way to either improve the light sensitivity? Or, can I put a timer on the light somehow, so that the motion detection is switched off until 11 pm when the kitchen lights are usually ( but not always ) off.

I'm not wanting this light to replace the room lights. I just want it to light up when people enter the room so that they don't need to switch the lights on just to do something briefly.

Edit: I think I know what the problem might be. The light detection appears to be on the solar panel side which is facing outside to the sun, and not to the room lights. So, at night time it doesn't sense the room lights are on.

Supplementary Question: Can I solve the problem by putting in a 5V photo switch like this one between one of the two wires to the LEDs?

connections to led

The red and black wires look like power to the LEDs which is at the top of the picture, and the brown and blue wires are I presume from the photosensor.

  • Sometimes you can partly block the photocell/photoresistor with tape. Takes awhile (many tries) to get it just right tho.
    – Tyson
    Jul 3, 2018 at 12:06
  • How is this thing powered? Sunlight? That won't work long. Learn more about how light works, light is an exponential scale so solarization has literally thousands of times as much energy as indoor light.... and our eyes are really good at hiding that fact from us. You cannot run a solar device (especially a cheapie not sized for it) on interior light. Jul 3, 2018 at 13:38
  • "... so that it charges during the day from sunlight."
    – isherwood
    Jul 3, 2018 at 16:05
  • @Tyson blocking the photocell isn't going to help. I want it to detect when my room lights are on so that it won't turn on when it detects motion while lights are on. Jul 3, 2018 at 22:06
  • @Harper gets about 6 hours of direct sunlight (through glass though) per day. Jul 3, 2018 at 22:06

2 Answers 2


Actually what you seem to desire is a motion activated light switch. I have one of these for a water closet - seems I would forget from time to time to turn the light off in that room; when I had traveled for a week or two - I would get that aargh! thought. So I bought and installed a motion activated light switch - I had the option to run it in normal mode or motion mode - works like a charm.

Take a look here:


EDIT 7-8-2018

Just to clarify: You desire the room lights to operate automatically when people enter the room EXCEPT when there is sunlight or enough light in the room already?

If this is the case Look no further a simple solution exists already See my link below ~

Leviton Motion Activated Wall Switch with Ambient Day/Night Light Hold Off Sensor

Leviton LED Motion Activated Wall Switch with Ambient Day/Night sensor

If perhaps you need a 3-way I am sure if you contact leviton product support they can provide you with options for your needs.

By your Edit of my post - I can see the above assumption is not what you want - you are only concerned about these solar lights turning on and off and the other normal mains room lights - don't matter one bit, you don't care if they are manual automatic or otherwise - you just want to add these additional solar lights - like big night lights if you will. That being the case you have only one route - and that is below - to use an interrupter for Day/Night but set for the lighting in your room , the big issue is you need it to keep the lights on when you have just the solar LED's but not allow the lights to be on when room lighting is sufficient. A small window between somewhat lighted and lighted - you will need to play with the setting on such a device for optimum - do not be surprised if it takes time to adjust it there and different conditions make it harder (also in time dust collects on sensors).

If you really desire to have those Solar Lights - you can use something this GEM in a 5V version: GEREE DC 12V Light Control Switch The Photoresistor Plus Relay Module Photosensitive Sensor.


Be sure to use the Control lines to interrupt the Lighting Circuit of those LED's and not the Photocells circuit, after all you just want the lights to be off when the room lights are on. You do not want any additional complexity in the detection circuits. This unit is pretty versatile - it is adjustable and can be mounted internal to your lights, except the sensor of course has to show up somewhere facing the room lights.

  • Well, the light already has a motion activated switch but I need it suppressed while there's light in the room. Jul 8, 2018 at 6:14
  • @GrahamChiu See my edit - here is a motion activated wall switch with an Ambient Day/Night Hold Off Sensor. If you prefer your outdoor solar lights, you are correct the photo cells see the dark and are motion activated enabled. Inhibiting the motion sensing when your room lights are on will prevent them from turning off as the motion would have turned them on and then you turned on room lights. When RM lights are off they would then turn off. You need to install an ambient light sensor circuit as in my edit above.
    – Ken
    Jul 8, 2018 at 10:08
  • I've edited your answer to clarify intent. I looked and couldn't find on Amazon a 5v version of the Geree light control switch. But presumably the 12v should work since I only need to supply 12V to the switch. The lights already have their own 3.2V power supply, and I only need to interrupt the line that controls the power to the LEDs? Jul 8, 2018 at 19:57
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    DC 5V/12V Light Control Switch Photoresistor Relay Module Detection Sensor XH-M131 s.aliexpress.com/6FFj6FJv which comes in a 5V version. Jul 8, 2018 at 20:13
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    Yes, I'm committed to using an external power supply but I don't imagine that this switch will draw much current so the power supply could be a small battery, or even a USB portable battery. I will try using the 3.2 v inside the light but suspect it won't work. Jul 8, 2018 at 20:49

I see that you are from New Zealand, so I don't know much about your dwelling and its location. What you are referring to, or attempting to do is called in the US Daylight or Sunlight Harvesting, and if you take the time to Google it you will find plenty to digest.

I do agree with @Harper on the price of sensors. A $4.00 photo sensor or motion detector is not designed to high tolerances as the price indicates. they pretty much do what they do, have no adjustments and usually what they do, doesn't do what you expect them to do.

Don't despair though, they do make sensors that will do what you want them to do. Then it's only a question of availability and affordability.

Good Luck

  • I think the problem is that the photo sensor is either on the solar panel, or, it's using the solar panel itself to detect light. And since I have the panel aimed outside, it's not detecting the room light. I had assumed that the light sensor was where the LEDs were which is the usual configuration I think. Maybe I can use some mirrors to reflect room light onto the PV panels to let it know the lights are on... Jul 3, 2018 at 22:09
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    I've uploaded an image of the internals and linked to a prospective photo sensor switch. Jul 4, 2018 at 23:23

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