Advice on scene for automating dust extraction

[morgan]

@DavidA

Hi everyone.

Very new to smart devices. I have purchased a Sonoff Pow Ring to detect power draw by a saw to then automatically turn on and off a dust extractor via an additional relay. I would like the dust extractor to come on when it detects the power draw of the saw, and turn off 30 seconds after it no longer reads the power draw.

I managed to set up a scene to turn the Ring on when detecting the power draw. And to turn off 30 seconds after the saw is no longer used (to ensure the remaining dust in the pipes will be cleared).

However, if i turn the saw back on within those 30 seconds (to do another cut) then the Ring nonetheless turns off (as it is simply following the action to turn off following the delay).
Is it possible to use scenes to only have the Ring turn off when it hasn’t detected the saw coming back on in those 30 seconds? Or to have a setup where following the Ring detecting there i no power draw, to perform another reading 30 seconds later and to only turn off the Ring if it doesn’t detect a power draw then?

Thank you for the help. Much appreciated.

Known problem with automation and ways to perform logic in ewelink. This can be bypassed, but not using ewelink alone. You have to use https://sequematic.com and therefore everything must have access to the Internet…
Maybe ewelink will improve it someday in the future, maybe not.

The problem here is the way the scenes are performed by ewelink.
If a scene is initialized, it will be executed until the very end, regardless of whether a new scene is initiated during it. In addition, this new scene is usually not included in the execution queue when another scene is running, which means that when the first scene ends, the second one was just a ghost that does not affect anything.

I wrote about it in other threads on the forum in the context of other Sonoff devices, but the concept of scene logic is the same.

Scenes does not enabled or disabled from a manual scene or from auto scene

So you want to have a stopwatch that will be reset every time the sensor is activated… You can achieve this using ewelink + https://sequematic.com On the ewelink side you will need two scenes. On the SM side you will need three sequences and pairing your ewelink account and one variable. [q9] On the ewelink side, you need two scenes, one to start the countdown and the other to change the value of the variable so that there are no mistakes, let’s call it STOP. On the SM side, we need thre…

I can show you an example…

When Ring detects current on the wire, it will start suction and send ON for STATUS.
Nothing else is happening at the moment.

When Ring detects no current, it will turn off the device, but only by sending OFF for STATUS.

Then TIME starts, which waits for 30 seconds and turns off the indicated Sonoff device, then sets STATUS as Null.

What if you start the saw, turn it off and then turn it on again within 30 seconds… The TIME sequence will be stopped and the device will not be turned off. Only turning it off again and sending OFF for STATUS will initiate 30s off again.
Unlike ewelink, stopping the sequence midway is possible and works.

You will have what you want.