# Sync not working with Usermods

**URL:** <https://wled.discourse.group/t/sync-not-working-with-usermods/5959>\
**Category:** Issues\
**Created:** [September 16, 2022, 6:13pm UTC](https://wled.discourse.group/t/sync-not-working-with-usermods/5959 "2022-09-16T18:13:07Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![StefDrums](https://yyz2.discourse-cdn.com/free1/user_avatar/wled.discourse.group/stefdrums/32/3136_2.png) [@StefDrums](https://wled.discourse.group/u/StefDrums)\
**Post date:** [September 16, 2022, 6:13pm UTC](https://wled.discourse.group/t/sync-not-working-with-usermods/5959/1 "2022-09-16T18:13:07Z")

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Hello,  
I would like to use some “slave” WLED PCB controlled from a “master controller”.  
I started testing using two PCB: one as slave and one as master. They are connected to the same wifi network, and when I turn on the “sync” and modify parameters from web interface on the “master” it works well.

The “master” is compiled with:

- -D USERMOD\_FOUR\_LINE\_DISPLAY
- -D USE\_ALT\_DISPlAY
- -D USERMOD\_ROTARY\_ENCODER\_UI

I also tryed with another circuit as “master” that has not Encoder nor Display but it has IR receiver and also in this situation the behaviour is the same: no syncing on the slaves when I press the IR remote buttons.

When I change brightness or speed effect (or any other parameter) nothing changes. I can’t understand why, anyone of you are facing the same issue?

Thanks!

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**Author:** ![tonyno](https://yyz2.discourse-cdn.com/free1/user_avatar/wled.discourse.group/tonyno/32/242_2.png) [@tonyno](https://wled.discourse.group/u/tonyno)\
**Post date:** [September 16, 2022, 10:01pm UTC](https://wled.discourse.group/t/sync-not-working-with-usermods/5959/2 "2022-09-16T22:01:28Z")

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May be better to look at virtual LEDs/DDP. That can be exact syncing while the normal syncing is not.

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<div class="post-metadata">

**Author:** ![StefDrums](https://yyz2.discourse-cdn.com/free1/user_avatar/wled.discourse.group/stefdrums/32/3136_2.png) [@StefDrums](https://wled.discourse.group/u/StefDrums)\
**Post date:** [September 16, 2022, 10:21pm UTC](https://wled.discourse.group/t/sync-not-working-with-usermods/5959/3 "2022-09-16T22:21:10Z")

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Dear @tonyno thanks for your hint.  
following this [readme info](https://kno.wled.ge/advanced/ddp/) its working.

I need some few clarification:

- is it necessary to define the LED strip lenght for each slave?
- does it work if i use RGB PWM or RGBW PWM instead of WS2813?

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<div class="post-metadata">

**Author:** ![tonyno](https://yyz2.discourse-cdn.com/free1/user_avatar/wled.discourse.group/tonyno/32/242_2.png) [@tonyno](https://wled.discourse.group/u/tonyno)\
**Post date:** [September 16, 2022, 10:56pm UTC](https://wled.discourse.group/t/sync-not-working-with-usermods/5959/4 "2022-09-16T22:56:11Z")

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Yes, each slave must be configured with what they have.

It works for all LED types.