Gauge not triggering BLYNK_WRITE


I have searched the forum but did not find anything related in previous topics.
Following is my setup. A Wemos D1 mini with a LDR connected to port A0.
In the sketch on this hardware the value of A0 is written every second to virtual pin 20.
In the Blynk app, I have a gauge which is connected to virtual pin 20 and it shows the value of A0 fine.
Another Wemos D1 mini connecting to the server with the same auth code tries to read V20.
This is done by a periodical syncVirtual on V20. But the corresponding BLYNC_WRITE(V20) is never called.
When in the Blynk app I change the gauge to for example a Value Display widget connected to V20, everything is working just fine. So my guess is that there is an issue with the gauge widget. The gauge is just another way of displaying a value just like the Value Display widget. So I cannot think of a reason why this behavior would be design intent.

Kind regards,


Gauge is an output (display) widget, so it syncs id a different direction (from server to smartphone)

Thanks for the answer.
Yes it is an output widget, but “value display” is also an output widget. Looking into the code of the server, the difference between "value display’ and “gauge” both under package cc.blynk.server.core.model.widgets.outputs is that the “value display” implements HardwareSyncWidget and an @override for send.

@Wim nice catch. Thank you! This is a server bug. Just fixed it. Fix will be released in few days with 0.17.0.

Initially we didn’t plan to use display widgets as SYNC widgets. However this use case seems valid for me.

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Hi Dmitry, thanks a lot !!