Some questions about external port - Possible simple new project?

Sometime this winter I want to build a unique “fire and ice” bar for my truck. Looking at getting a couple 144 led/m 5050 format WS2812B strips and going from there.

I am looking at powering the Arduino from the truck and controlling the lights via the Arduino.

Looks like using an M2 might not be a bad choice to do this but not sure.

When I look at the cost of safely driving the Arduino from the truck, then allowing inputs for the lights (l/r turn signals, brakes, reverse, and running lights… Total of 5 12 volt inputs)

With these they only need 1 data line and I will have 2 light bars.

Looking at the schematics should I assume that the UART3 is just breaking out the pins directly from the processor and should not effect anything else? So I should be able to use the pins directly which would allow me to talk to both of these light bars?

There is an Arduino library to talk to these light strips so If I can use an M2 for this process it shouldn’t take me long to configure it to work. Could also use an input to be used as an alarm input if so desired as well. (Flash LEDs sort of thing when the alarm is set although probably not a good way to use up the vehicles battery…)

Trying to see if it makes sense to try interfacing into the truck using the M2 as opposed to trying to build my own custom one off. The light strips I want to use are available for like $30 apiece for a meter in length.

The power to the strips would be powered by a different power source and just tie the ground to the M2. Likely use a relay controlled by the M2 to turn the strip on and off.

Assuming my assumptions are correct I could use the FastLED library, the inputs and have something done in just a few hours. But I am hoping @josh or someone else that knows the M2’s hardware can verify that the UART3 pins can be directly accessed for this. Still have to verify the voltage the 2812 strips need to communicate because if they need 5 volts I will need to get some voltage convertors from the M2’s 3.3volt lines.

UART3 pins are broken out at J5 on the interface board. You can use also the XBEE UART port if you need.

For this project I am looking at just using the pins assigned to the UART port. I only need 2 pins so as long as I don’t try to use the serial port I am thinking I should be good but have to get it to 3.3 volts. The 3.3 volts is compatible with my Nextion but I don’t know if it will work directly with a WS2811/12

The WS2812b normally works with 3.3v logic level - that’s my experience by now. The fastled library is great and compiles with the Due so you should be ready to go.
I have some LEDs with WS2812b around and the M2 arrived finally so let me know if you want me to test anything!

Do you have a WS2812 light strip or free LED’s?

With the M2 it can only power a couple LED’s from its power supply.

Can you try to control the WS2812’s from the pins to the UART3 connector? Both the rx and tx? I will likely just get a light strip and try it myself with an automotive 12v to 5volt convertor.

Guessing since it is a data out I can try it and see if it works with my M2 and it shouldn’t damage it. Just won’t work if requires 5 volts.

The power supply has to be 5v but the data level can be 3.3v. I’d suggest to power the leds externally from a converter or whatever and bridge GND of both supply and M2, as you already had in mind.
I have strips with 144 LEDs/m and will give it a try later today.

Thanks. I MAY not use the M2 as I have a Due board somewhere and a Prototype board for it. If I can get a 5 volt supply to drive the lights It makes sense to use it to run the Processor as well. If I use a simple voltage divider I can reduce the voltage down or go directly to the BCM to pull the low level signals.

But would certainly be nice to know if the M2 can be used for this. Assuming it works I may still try to get it working with the M2 in my truck for now but would require me getting another UTH version.