# Unstable PWM / Jittery Servo control Pi 3

**URL:** <https://discourse.nodered.org/t/unstable-pwm-jittery-servo-control-pi-3/31840>\
**Category:** Hardware\
**Created:** [21 August 2020 14:40 UTC](https://discourse.nodered.org/t/unstable-pwm-jittery-servo-control-pi-3/31840 "2020-08-21T14:40:28Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![fraser](https://avatars.discourse-cdn.com/v4/letter/f/6de8d8/32.png) [@fraser](https://discourse.nodered.org/u/fraser)\
**Post date:** [21 August 2020 14:40 UTC](https://discourse.nodered.org/t/unstable-pwm-jittery-servo-control-pi-3/31840/1 "2020-08-21T14:40:28Z")

</div>

I'm using a Pi3 and the rpi-GPIO node to control a servo. The servo is connected to pin 12 (GPIO 18/PWM0) The output doesn't seem to be stable, the servo moves but jitters when it should be still, suggesting that the PWM is being generated in software, not hardware.

Can anyone suggest how I can tell if the hardware PWM is being used? Or anything else that may enable to to trouble shoot this?

---

<div class="post-metadata">

**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [21 August 2020 14:53 UTC](https://discourse.nodered.org/t/unstable-pwm-jittery-servo-control-pi-3/31840/2 "2020-08-21T14:53:46Z")

</div>

if using the standard gpio node then no it is not very stable... If you use the pigpiod node instead is it a lot more stable (as the timing is generated in a separate process.)

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [20 October 2020 14:54 UTC](https://discourse.nodered.org/t/unstable-pwm-jittery-servo-control-pi-3/31840/3 "2020-10-20T14:54:06Z")

</div>

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.