How to connect rs-online 257-149 flow sensor

[Albertoo]

Hello,

I have a [flow sensor](https://nl.rs-online.com/web/p/flow-sensors/0257149). I would like to connect this to an esp32. The [specsheet](https://docs.rs-online.com/0b22/A700000008879971.pdf) however makes me feel stupid. I am not sure whether i can just connect it to the esp or that some more parts are needed. It says the electrical supply voltage is 4,5 to 16vdc and 10mA. However, the delivered [instruction leaflet](https://docs.rs-online.com/facd/0900766b81501390.pdf) says the absolute maximum ratings for the diode (page 4) is 3.0V...

If i use a 5v source to power the esp on the vin and the gnd, and i connect this 5v also to the G, V+, +VCC and 0V (page 4 of the spec sheet), can i then connect Vout to the esp and measure the frequency and then use that to compute the flow thought the sensor? Thanks in advance.

[ESP_Sprite]

It's not a very well specced component, that's for sure. I think you should indeed connect G and 0V to ground and +V to 5V, but + (where I assume the LED is connected to) via a series resistor that limits the current to 10mA to 5V. Furthermore, the ESP32 doesn't really like 5V on its inputs, so you could add a 3.0V zener from the output to ground to limit that.