Orlandoo MX0034 light bar question

[ChilliBreath]

Hi all,

I want to install some lights on one of my micro crawlers (SCX24), and have 5V BEC ports for this purpose.
I ordered a light bar from orlandoo, but am struggling a bit with how best to hook it up to my electronics.

Apparently, it takes 3V to drive, and has a 3 watts power rating - so requiring 1A. But to me this seems a pretty high current. So I guess I am looking for some confirmation on how best to set it up.

For now I think the most straightforward method would be to get a voltage step down circuit which I can power with 5V from the BEC port, and set that to 3V output. If need be I would even be willing and able to piggyback the step down directly to the battery if that saves the ESC.

However, I'd rather just set a simple resistor in series, but a 2 volt drop and a 1 amp current means I need a 2Ohm resistor capable of dissipating 2 watts, which is not entirely straightforward in terms of hardware (although I suppose I could set 5 10-Ohm resistors rated 1/4W in parrallel and be safe too). But still, the power draw seems pretty intense.

Does anyone have experience with this particular light bar, and if so, how did you power it?

 

[Ots]

Easiest might be to patch in the Orlandoo light board controller (there are a couple of them) which was made for the light set you bought. It has more than you need but it should work.

 

[ChilliBreath]

Thanks, I'll consider that!

Although at first glance a buck converter like this one would be cheaper and have less footprint.

 

[Ots]

https://www.amazon.com/Anmbest-AMS1...dp/B07CP4P5XJ/ref=psdc_10967761_t1_B083RDCPYB

This one is a regulated 3.3V output while the one you sited has an output that will vary with input. Either way it's not a critical application and either should work.

I prefer the Orlandoo one as it was designed for the specific application you have (as well as some others you won't use).

 

[ChilliBreath]

I am a stubborn jacka$$ so ordered a step-down converter in the end - one where I can adjust the output voltage with a potmeter so I can set it to any desired value.
I also found someone on youtube who simply powered it via a 20mA current regulator, which apparently works fine, so I'll call that plan B - using the 5V off the BEC and subtracting the 3V required for the light bar leaves a 100Ohm resistor to drop the current to 20mA.
I use an Arduino and breadboard to try out any electrical schematic first so I can check for brightness, heat build-up, ...

 

[Ots]

Great - I love it! It's these kinds of experimentation that allow us to learn cool things that we will use not just now but later as well.

Let us know what works best.

 

[ChilliBreath]

I got it in the mail today, and also got the step-down converter. I tried two set-ups:

1: I hooked up the light bar to 5V with a series resistor. I tried 56 Ohm (for about 40mA) and 80-ish Ohm (closer to 20mA). Both gave strong light; the 56Ohm set-up obviously a bit more than the 80-ish ohm.

2: I set the step-down converter to 3V. This also gave off a ton of light. At 2,8V, still a lot of light. At 2,5V I got close to the forward voltage and got very dim light.

I think the safest way forward would be to use the step-down converter. I can set it relatively accurate (though it's somewhat finicky) and it's very easy to turn it down a notch if I feel more heat build-up than I'm comfortable with.

Still a bit in doubt about using a series resistor. Apparently I can power the thing with 20-ish mA and/or 3-ish volt, but the website stated 3V and 3W, meaning 1A and that seems like an enormous amount of current fur such a tiny fixture - let alone the wire gauge. Those leads are TINY! :shock:

I include a picture of the light bar (4cm long) with a standard resistor for scale, and the step down converter. Really liking how small the converter is Note how incredibly small those leads are.