NodeMCU With Simple Water Sensor

[fabridelo]

Hi to all
I’m new to the group, my name is Fabrizio and I’m really a beginner.
I would like to turn a LED on Blink when this sensor becomes off / on.
I connected the sensor following this scheme

Arduino – Controllare il livello dell’acqua in un serbatoio

and this is the sensor.

https://it.rs-online.com/web/p/products/3389772/?grossPrice=Y&cm_mmc=IT-PLA-DS3A--google--PLA_IT_IT_Automazione_E_Controllo_Di_Processo--Gestione_Fluidi--PRODUCT_GROUP&matchtype=&pla-634860351739&&cm_mmc=IT-PLA--google--PLA_IT_IT_Automazione_E_Controllo_Di_Processo-_-Gestione_Fluidi&mkwid=s_dc%7cpcrid%7c76742436407%7cpkw%7c%7cpmt%7c%7cprd%7c3389772&gclid=Cj0KEQjw8-LnBRCyxtfMl-Cbu48BEiQA6eUMGnOskGzz_xWLmAyNf_mAirKIWzXrH9krH8ass2VfVEgaAgY_8P8HAQ&gclsrc=aw.ds

I connected everything to port D8 and use an MCUesp2866.
Someone can give me some help so I can do some testing.

Thank you

Best Regards

[PeteKnight]

D8 = GPIO15, which isn’t a great choice if pins:

ESP8266 GPIO pins info, restrictions and features

hi blynkers! the esp8266 mcu is widely used in iot projects. however, most gpio pins on this mcu have special / multiple functionality and are not safe to use in all circumstances. these “features” are still not well documented and not explained in a friendly manner for newbies. i see lots of cases when the “issues” are simply caused by not knowing which pins to use in which case. [esp8266 pin features] here is a basic table for startup. i’ve collected the info from various sources on the i…

Your float switch is just a simple on/off device. One side is connected to D8, where is the other side connected to?

This sketch builder example would be a good starting point…

Blynk Example Browser

Pete.

[fabridelo]

thanks for answering PeteKnight
the other part of the sensor is connected to the 5v with a 10k resistor. When the sensor is down (no water) there should be 5v on pin D8.

Thank you

Best Regards

[PeteKnight]

@fabridelo

the other part of the sensor is connected to the 5v with a 10k resistor. When the sensor is down (no water) there should be 5v on pin D8.

Are you sure?

Pete.

[Blynk_Coeur]

5v on pin D8 is much more than the nodemcu can admit.
the Max is 3.3v !
you risk to burn it.

[PeteKnight]

And a 10k resistor in series with the 5v supply will give such a low voltage when the switch is closed that the NodeMCU will still see Pin D8 as LOW.

The sensible approach would be to use the 3v3 pin of the NodeMCU connected to one side of the switch and the other side to a more appropriate pin than D8.

Pete.

[fabridelo]

Hello everyone

thank you very much, you answered me very quickly.
noting that my floating sensor behaves like a switch I used this other scheme.

NodeMCU Project—Button Control LED

But when I check with the tester I always measure 4.8V.
This is right or not?
I have another free pin D0 but I don’t understand if it can go well

Thank a lot

Best Regards

[fabridelo]

sorry

I have not seen the scheme well, the voltage is 3.3V.
Now I just want to know if D8 and D0 are pins that is good for my sensor

Best Regards

[PeteKnight]

@fabridelo

I just want to know if D8 and D0 are pins that is good for my sensor

I’ve already you that they aren’t, see the second post in this thread.

Pete.

[Blynk_Coeur]

D8= boot failure if pulled high