ESP8266 Community Forum

- Tue Feb 07, 2017 6:22 pm #62239 Hello

As newbie in esp8266 world, i spent many days trying to control wemos using 2n222a npn transistor and an arduino

my plan is to keep the arduino running most of time in deep sleep mode,
The arduino will wakup periodicaly and turn on the esp by switching on transitor.

The problem i,m facing is concerinig the resistor value i should use to limit the current to the base.
I just can,t get it work whatever the value i pick.

can anyone help with this?

tnx to you all.

- Tue Feb 07, 2017 10:37 pm #62243 Try 330 Ohms.

But using a transistor this is a good solution. You have a difference in grounds as one problem. I think you should try using the CHPD pin since that is what it is for. Turning the ESP8266 in a low power state.

- Wed Feb 08, 2017 2:43 am #62251

Try 330 Ohms.

But using a transistor this is a good solution. You have a difference in grounds as one problem. I think you should try using the CHPD pin since that is what it is for. Turning the ESP8266 in a low power state.

Tnx a lot for your answer.
I'm at work right now, I will try with the rep ohmes when I return home, but a have a small question what are the variables you used to get this value ?

The CHPD pin is a good solution but I don't think its going to work with wemos as all the connexion are premade.

Tnx again

- Wed Feb 08, 2017 5:27 am #62257 Or, why not, a tiny MOSFET as a high side power switch for your ESP8266 module.

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