Wemos D1 Mini Pin CH_PD / EN unclear

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Dondolo
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Wemos D1 Mini Pin CH_PD / EN unclear

#1 Post by Dondolo » 10 Feb 2020, 07:23

Hi there,
I would like to replicate this water sensor, but instead of the ESP8266 F with a WemosD1 Mini.

Image

http://heinz-otto.blogspot.com/2018/0 ... 266.html

Only the wiring from pin CH_PD / EN is unclear to me, the Wemos doesn't have that.
Does anyone have time and can help.

Greetings Dondolo

TD-er
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Re: Wemos D1 Mini Pin CH_PD / EN unclear

#2 Post by TD-er » 10 Feb 2020, 11:40

It is normally tied to 3v3 via a resistor and a capacitor.
This allows to introduce a 'delayed boot' of the ESP when you apply power.
So the Wemos has this pin already setup for you or else the ESP would not boot at all.

In your schematic, it was probably meant to really power down the ESP when not used to save battery power.
If you need that, then I think using a Wemos module is probably not the best choice anyway as that one also has an USB to serial controller and a voltage regulator that doesn't have the best quiescent current any way.

Dondolo
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Re: Wemos D1 Mini Pin CH_PD / EN unclear

#3 Post by Dondolo » 10 Feb 2020, 12:48

Hello Td-er,

Thank you for your prompt reply.
If I understand it correctly, then I would have to put the connection that goes to CH_PD / EN with the Wemos to 3.3V Vin.

The idea behind the circuit diagram was that the WEmos is deeply asleep and periodically issues a status message (i.e. wakes up briefly), but should then make a real noise in the event of a water alarm.

Sure, the ESp8266F is certainly the better choice for power saving functions, in the second step.
Greetings Dondolo

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