Connect a 3V light to GPIO

Hello everyone,

I have got this 3V light which has a red and black wires. I checked by connecting the red one to a 3V pin on my Raspberry Pi 4 and the black one to a ground pin and the light switches on nicely. Now, I would like to control it using Home Assistant.
From what I found connecting and controlling a fan on GPIO, we need to put a resistor and transistor:

What do I need for my light? Is it the same circuit to build? I am sorry as I am learning slowly electronic.


Most importantly, what kind of light is this?

It is kind of a unique piece I am trying to connect, not a standard model. After dismounting it, I can see six LEDs connected.

There are so many possibilities here.

Have you tried using a multimeter to see what voltage is already being applied across the existing circuit? Is this possible?

Thanks! I just bought a multimeter, I will receive it in a couple of days. A label on the light says 3V. That is the only info I have for the time being.

Hi Matthew,
I tried and it says 0.00 mV… It is weird because I tried again to connect it to a 3.3V pin on my Rasperry Pi 4 and it switches on.
Maybe I am not using my multimeter properly. But I used it the exact same way to measure voltage on a small AAA battery and I found 1.5V which is correct.