ESP8266 Community Forum

- Mon Feb 13, 2023 3:58 am #95982 Hello,

I have designed a PCB to run an ESP-12F with DHT-22 temperature tumidity sensor on battery.

I have no experience on designing a PCB so If anyone can point out if there is a problem I'd highly appreciate it.

I wanted to reset from pin to be able to wake from deep sleep also from the switch. I don't know if that is possible.

- Mon Feb 13, 2023 4:59 am #95984 Main issue I see is that your reset switch will short GPIO16 (mormally high) to GND when pushed. You want o include a diode , preferably schottky between GPIO16 and reset to prevent the conflict.

I would also include an electrolytic capacitor e,g, 220uF on the regulated 3.3V regulator output.

The 10K pull down on GPIO15 for start up is marginal in my view. I like to use 4k7.

- Mon Feb 13, 2023 5:41 am #95986

Main issue I see is that your reset switch will short GPIO16 (mormally high) to GND when pushed. You want o include a diode , preferably schottky between GPIO16 and reset to prevent the conflict.

I would also include an electrolytic capacitor e,g, 220uF on the regulated 3.3V regulator output.

The 10K pull down on GPIO15 for start up is marginal in my view. I like to use 4k7.

The direction of the current is from GPIO16 to GND when the switch is pressed so if I block the current with diode I think I will also be blocking the wake up signal from GPIO16 to RESET. And if the diode is placed other way around there is still a short between GPIO16 and GND.

Am I wrong?

This one still shorts GPIO16 to GND when switch is pressed


This one blocks GPIO16 signal

- Tue Feb 14, 2023 7:29 am #95992 The correct second one doesn't block the GPIO16 signal. During wake up the GPIO16 pulses low and this will pull the reset line low through the diode.