Use digital input as pulse frequency counter (for wind speed sensor)

[Gerd_]

Hello,

Most of the wind sensors are pulse based (not voltage based), that's also the case for my Somfy Soliris wind sensor

I want to replace the Somfy control unit with a Shelly plus 2 with add-on, to make my cover connected. See picture below

Is there a way to use the digital input of the Shelly plus add-on as pulse frequency counter for the wind sensor?

An easy answer would be to build or buy a frequency to voltage converter then feed the voltage to then Analog input, but this is not elegant, requires an additional power supply, and the analog input will anyway be needed for the light sensor, so it is already used.

Is there a way, by scripting, to use the digital input (or a 1-wire bus input) and get the pulse frequency out of it?

Does anyone has experience with this?

Thank you

Gerd

[thgoebel]

Shelly UNI plus has an impulse input suitable for counting pulses and measuring frequencies!

[Gerd_]

Thank you for your reply. The problem with Shelly Uni is that it can not control shades… In addition it can handle only low-voltage stuff but not 220VAC motors.

Now we could imagine having a Uni dedicated only for measuring the wind and send it to a plus 2 to retract the shades when there is too much wind. Unfortunately this is not reliable enough because it relies on a Working WiFi link. In case WiFi is down, the plus 2 would miss the retract command. The awning I need to control is a big and very expensive one. Last failure to retract cost me nearly $4000.- for the repair… I am therefore looking for a reliable solution that works fully locally without relying on WiFi (WiFi is just for handling commands but not for safety actions!)

Any other idea?

 

PS. Can the Uni really measure the frequency of the pulses? Or only number of pulses (like for a water meter). My understanding is that the Uni can only count pulses. We could of course imagine writing some script that convert pulse counting into frequency, but I am not sure how accurate and reliable this would be.

I really think that there is a need for a more flexible add on with multiple AD converters as well as multiple more powerful digital GPIOs (that could also be used for 1-wire or I2C or SPI bus).

 

[thgoebel]

The Shelly UNI plus can measure frequencies, indeed.

To adapt consumer circuits supplied with mains voltage some kind of intermediate relays are available (third party products).