Backlight for wall clock

Hi there,
I’m looking at using the Round Semi-Circle Backlight LED - 50mm Diameter or the small 12mm-x-40mm as a backlight on a wall clock but need some advice on which regulator to use and full set up with battery and possibly a motion sensor.
Thanks in advance - I know nothing about electronics and lighting… that’s pretty obvious! :crazy_face:
I’ve used a torch underneath for photographic purposes in one of these photos.

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Hi Tania,

I’ve found the small backlight panel you referred to but I’m not sure which round backlight LED you were also interested in, can you share the SKU number of that one so I can look up the specifications? It should be listed just under the product name on our website.
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The datasheet for the small backlight module shows that it is really just an LED with a big diffuser around it so we need to find a way to supply it with 3.3V@15mA to meet it’s power requirements.
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The simplest setup will be a AA battery holder with a higher voltage and a current limiting resistor to keep the current in the LED within its operating range. You can calculate the resistor needed using this guide.

The next level of complexity would be to use a battery supplying more than 3.3V and a regulator to maintain the voltage supplier to the LED at 3.3V, the regulator below would work for that.

As far as motion-sensing goes you would need to decide on what kind of motion sensor to use, then either build a circuit to trigger the light from the output of the sensor or incorporate a microcontroller to interpret the sensor and drive the LED when required.

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Thanks … The round one is the ADA4882

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Hi Tania,

Thanks for confirming, the round one is similar but has 2 LEDs inside it. So it needs to be operated around 3 Volts with 30mA of current drawn.

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