I want to get RPM using ESC called JHEMCU EM-40A

[gh24526]

Hello.
I would like to get the RPM as described in this post, but I am not sure if I am getting the data.

Platinum HV 200A ESC RPM signal to Navio 2

Hello, I am working on a traditional helicopter project for my company and we must have the RPM telemetry to fine tune the helicopter for different payloads and flying conditions. The helicopter uses a Hobbywing Platinum HV 200A ESC that provides a RPM signal cable. How can I read this signal from Navio2 to be available among the telemetry data? Thank you very much.

The ESC I am using is JHEMCU EM-40A and the FC is Navio2.
I connected the CURR wire of the ESC to pin 5 of the servo rail and set
echo 504 > /sys/class/gpio/export
echo “in” > /sys/class/gpio/gpio504/direction
I then entered
cat /sys/class/gpio/gpio504/value
but it displayed 0.
Does this mean that I am not getting any data?
I would appreciate your advice as I would like to eventually view the data in Mission Planner.
Thank you in advance.

[olesia.riman]

Hi @gh24526,

We haven’t tested JHEMCU EM-40A, so it’s difficult to suggest something for the code. Hopefully, someone from our users who’s experienced with it can advise you on something.

[gh24526]

Thanks for the reply.
If you have not tested the JHEMCU EM-40A, does that mean you have tested other esc?
If so, were you able to measure the RPM?
Also, could you please tell us as much detail as possible about the esc and the wiring and cords you used at that time?
Thank you in advance.

[olesia.riman]

We have some information about ESCs’ wiring in our documentation.. I’ve also found some threads on our forum about RPM:

Platinum HV 200A ESC RPM signal to Navio 2

Hi Bruno, As Navio2 possibilities depend on ArduPilot possibilities, I started with researching their docs. That’s what I found: it’s supported, and there is a specific RPM library you need to install. Please check the guide. Also, as I got, you’ll need to set PWM as GPIO for this. Here’re the tips on how to do it.

How can I know the motor rpm in real time?

I would like to make sure that the motors connected in the right order and stabilize correctly, without props before first flight, is there any option to see how much energy/rpm any motor get ?

I suggest you can start there.

[gh24526]

Thanks for your reply.
I did my own research and saw an article that it is not possible with the existing firmware of JHEMCU EM40-A.
I will look into another way to get RPM without using ESC.
Thank you very much.