PWM controlled relay wont trigger

Other Hardware Robotics
1

Hi!

I currently have a operating signal system for my model railroad. I am attempting to take a PWM/servo signal and operate a relay. So I purchased one of the these PWM relay boards.

The problem: I cannot find a happy range to make this relay activate. If I hook a servo motor to the same pins, the servo will step through the ranges as I adjust them in the code just fine, but I cannot find the correct range that this PWM relay likes.

The total servo range values for close/throw are 0-4096. Although the extreme ends of these values are actually outside the range of a servo motor and will cause it to max out and buzz. 500-1000 works well.

I know the code is good because the servo responds to the changes I make for throw and Closed just fine.

Anyone have any experience says with these? Thanks.

LICHIFIT Q1 RC Aircraft Relay Switch PWM Model Remote Control for Drone FPV Quadcopter Launch Spare Parts https://a.co/d/5MdEKuy

IMG_9362
IMG_93623024×4032 2.91 MB

IMG_9361
IMG_93612109×1582 1.52 MB

2

I think you are misunderstanding what this relay does. The PWM signal it talks about is a PWM signal from a remote control multiplex of signals. This is a different sort of PWM than one required to directly drive a servo. The signal composition of the PWM is not the same on the two systems.

3

A Servo signal should work. Perhaps you have mismatched the wires? Missing power? What with a steady (hi/lo) signal?

4

Which arduino are you using?

5

Three of the reviews say they worked great and 4 of the reviews said they were total crap.
So I would say you have around a 40% chance of having a good relay.

6

Mega. Turning the servo on and off with another program called JMRI.

7

It seems to be hooked up correctly. I stepped through the entire range and tested the actual servo to check that it the signal was working. It does say Futaba not supported on the description (another brand of RC radio). Maybe it is something with the type of PWM?

8

I'd try HI (100%) and LOW (0%). If that does not change anything then I'd not spend any more time on a research of those buggy boards.

1 Like
9

I think I will try and hook it into a working name brand RC receiver. If it triggers, it must be some compatibility issue with the PWM? If it doesn't, it must be a faulty board?

Thanks!

Kennedy

10

Maybe a little late to the discussion, but maybe it will help someone else.

I just put 2 of these on my K9 robot. The relay has to receive 1500 pulses when connected to power. That is its neutral position. At 1000 pulses, one relay will switch on. At 2000 pulses, the other relay switches on.

I wanted to use this as a safety relay for my drive motors, but outside of soldering some jumpers on the board, there is no way to do it.

11

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