r/ExpressLRS

I’m not that deep into ELRS yet, so I’m not entirely sure how I should approach this.

Basically, I have an RC car and I’d like to use some of the buttons/switches on my RadioMaster Boxer ELRS to control the LEDs on the car.

The LEDs are wired using a 3-wire cable, similar to a servo. The anode is permanently connected to the positive supply voltage, and I have a MOSFET that connects the cathode to GND when it receives a signal on the signal wire.

From what I understand, the usual receiver output modes are PWM with frequencies such as 50, 60, 100, 160, 333, or 400 Hz, with pulse widths like:

• Normal: 988–2012 µs (center 1500 µs)
• Extended: 885–2115 µs (center 1500 µs)
• Half pulse: 494–1006 µs (center 750 µs)

None of these seem particularly useful for my application, since the LEDs would never really be fully off.

However, I also saw in the documentation that ELRS receivers should support 10 kHz PWM with 0–100% duty cycle or even binary ON/OFF (HIGH/LOW) output. That would be exactly what I need.

The problem is that when I look at different ELRS receivers, I can’t seem to find much information about whether their outputs actually support these modes. As far as I understand, this is something that should be configured in the receiver settings, but I’m not sure how it works in practice.

So my questions are:

1. Can I configure any ELRS receiver output to act as a simple digital ON/OFF output?
2. Do I need a specific receiver that supports this, or can most ELRS receivers do it?
3. How would I configure one of the buttons/switches on my Boxer to control that output in this way?
4. I’d also like to implement turn signals. Can this kind of blinking pattern be configured in ELRS/receiver software, or would I need additional hardware (e.g. a small microcontroller, 555) to handle the blinking?

I’m mainly looking for the simplest/cleanest way to do this without adding unnecessary hardware.