Release/Stop Driving Servo?

[jayekub]

hi, i'm successfully controlling a servo over mqtt using the Servo command. however, i'd like to stop the servo pwm signal after a few seconds to conserve power (and avoid the subtle noise it makes). i've tried sending a GPIO 0 command but that seems to have no effect after the Servo command is used. i need to reboot to get it to stop.

is there a way to do this with ESPEasy? i had this working fine with nodemcu, but switched to ESPEasy to get away from worrying about memory constraints...

[jayekub]

started poking around in the code and i don't see Servo::detach() called anywhere, so i'm guessing the answer is "no". i'll try coding up something to address this and will contribute back if it works.

[fz1]

Hi,
I have exactly the same problem! I have already tried to pull the Servo GPIO LOW, but without success. It keeps "sending" the PWM signal

[SimtechBen]

I am having the same problem. The servo keeps buzzing or ticking once it reaches position. I am trying to control shutters with it and if there is any small load on it, the servo ticks to try and maintain position. This is not desireable as the general position is fine with me.

[toffel969]

I have the same problem. It kills the servos rather quickly... a fix would be desirable.

[vader]

If it needs no force to keep the position, just detach the servo from ESP and enjoy the silence (a mod of the source code is necessary).

[TD-er]

I added an issue about this on Github.
https://github.com/letscontrolit/ESPEasy/issues/672

[vader]

I'm not sure if it is a real issue. The servos just do what they have to do: Keep the set position.

[TD-er]

I'm not sure if it is a real issue. The servos just do what they have to do: Keep the set position.

But do they change position if you go to 0% duty-cycle?
Other change could be to set an upper and lower limit on the allowed PWM value.

[grovkillen]

Yes, aren't they supposed to work that way? To be able to stay in the position with no power applied you'd need more expensive servos?

More on the subject:
https://arduino.stackexchange.com/q/24783

[vader]

I'm not sure if it is a real issue. The servos just do what they have to do: Keep the set position.

But do they change position if you go to 0% duty-cycle?
Other change could be to set an upper and lower limit on the allowed PWM value.

I haven't tried it yet. For my purposes I detached the servo from ESP. So it has no power at all (I hope...) but reverts a bit back due to the mechanical force.

[Jeff]

I have the same problem, it's for my catfood, it's not important to keep the position.
The noise is stressful
How to do ? I can use mqtt command (nodered) or url commad (domoticz).
Help us

[toffel969]

I'm not sure if it is a real issue. The servos just do what they have to do: Keep the set position.

But do they change position if you go to 0% duty-cycle?
Other change could be to set an upper and lower limit on the allowed PWM value.

I haven't tried it yet. For my purposes I detached the servo from ESP. So it has no power at all (I hope...) but reverts a bit back due to the mechanical force.

Hi vader
Can you elaborate on necessary changes in source to de tach servo?

[kimot]

Simply power servo through transistor driven by another gpio pin and switch power off, when servo is not driven to move.
But servo can move under some force then, because it is not held in its position by motor force.

[toffel969]

Simply power servo through transistor driven by another gpio pin and switch power off, when servo is not driven to move.
But servo can move under some force then, because it is not held in its position by motor force.

Sure thats a way to do it, but I think there must be a software fix too using the detach command in the arduino source code.

I think there are many applications where a holding torque through servo power is not required, but servo buzz is critical.

[waspie]

edited the servo file to detach after 2 seconds. works perfectly.

[toffel969]

edited the servo file to detach after 2 seconds. works perfectly.

Which file (name of the ino) and what source code has been changed ?

[waspie]

edited the servo file to detach after 2 seconds. works perfectly.

Which file (name of the ino) and what source code has been changed ?

i was in process of finding it....
I've been using mine like this for many months now without issue


it's _P001_Switch.ino

find:

Code: Select all

            {
              case 1:

                //IRAM: doing servo stuff uses 740 bytes IRAM. (doesnt matter how many instances)
                #if defined(ESP8266)
                  servo1.attach(event->Par2);
                  servo1.write(event->Par3);
                #endif
                break;
              case 2:
                #if defined(ESP8266)
                  servo2.attach(event->Par2);
                  servo2.write(event->Par3);
                #endif
                break;
            }

replace with:

Code: Select all

            {
              case 1:

                //IRAM: doing servo stuff uses 740 bytes IRAM. (doesnt matter how many instances)
                #if defined(ESP8266)
                  servo1.attach(event->Par2);
                  servo1.write(event->Par3);
                  delay(2000);
                  servo1.detach();
                #endif
                break;
              case 2:
                #if defined(ESP8266)
                  servo2.attach(event->Par2);
                  servo2.write(event->Par3);
                  delay(2000);
                  servo2.detach();
                #endif
                break;
            }

change delay (ms) to whatever you need. if your servos are where they need to be in half a second change it to something like 600.

[toffel969]

thx

[mrwee]

Hi Guys,

Is it possible to add the 'detach feature' as e.g. a command in ESP Easy? I'm not capable of changing the source-code and re-compiling, so it would be a nice addition

[TD-er]

Hi Guys,

Is it possible to add the 'detach feature' as e.g. a command in ESP Easy? I'm not capable of changing the source-code and re-compiling, so it would be a nice addition

What a coincidence
Someone made a PR for this... https://github.com/letscontrolit/ESPEasy/pull/1619