ESP8266 Community Forum

- Sun Feb 28, 2016 9:31 am #42047

1- If GPIO2 is used as input, you need to consider that the sensors provide HIGH level on idle, otherwise the ESP won't boot.
2- I means : in your current schematic, the switch is badly located, it is really shorting power, not shorting the GPIO0, it needs to be moved the other side of the PullUP.
3- It is up to you ! MOSFET such 2N7000 or AO3402 are cheap as well.
4- no problem.
5- No ! you absolutely need GND and GND2 to be connect together, otherwise your MOSFET will be in some kind of "floating mode". If you wish to have them separated, you will need some opto-coupler circuits.

thanks a lot to take such time to have a look and help people like me here


2-i understand now , i will move the button the other side to be directly connected to the GPIO0 Pin.
3- i will check for that.
5- i think as the GND is coming from 5V power supply and GND2 is from the external 12V power supply should be seprated.
what is the effect on other parts of schematic ?

once i update your suggestions i will post it for last review.

- Sun Feb 28, 2016 9:47 am #42048 5- It doesn't matter if VCC2 is 12V or 50V. If GND and GND2 are not connected together, than the gates of the MOSFET don't have any reference since ESP GPIO output voltage as no reference to GND2. Trust me (I'm doing EE since more than 35 years), it really needs to be connected together. Otherwise you will need opto-couplers.

- Sun Feb 28, 2016 10:25 am #42050 I would have to agree here with Martin, Common the grounds like martin I have been doing Electronic engineering for over 35 year.

Take advice from experts!

Dans

- Sun Feb 28, 2016 10:32 am #42052 PS:

I would be inclined to add an electrolytic and ceramic capacitor at the output of your ac to dc converter 5 volt end after looking at the specs for this module. 100uf & 100nf for decoupling.

Good luck

Dans