Resetting of NodeMCU ESP8266 in deep sleep

Question

I have been doing a project as my first project to learn ESP8266 applications. My project is a temperature and humidity values data logger and upload the data to Thingspeak.

The sensor used is DHT11.

I am using a NodeMCU ESP12 v0.9 board as in this image:

Connection diagram is:

The code you can see is this.

The problem that I faced is:

When it is running and the battery dies the whole system doesn't restart from the start. It remains in sleep condition, I have waited like 30 minutes thinking the nodemcu would wake up from sleep but no it doesn't.

I want to know if there is reset code that can be used or a push button or switch should be used to reset.

Answer 1

Connect a button to RST pin on NodeMCU (3rd pin from bottom left) and then to ground. When you press the button RST is pulled low and NodeMCU should reset and wake up fro deep sleep.

Answer 2

You need the RST to D0 connection if you are using DeepSleep

As the RST pin is being used for deepsleep it is not possible to connect it to GND. You will need a Normally Closed push button or a flip switch. It is no possible to use RST for deepsleep and as a reset.

Answer 3

This is an old post but people may find it when looking for a solution. What I found:

Some ESP8266 modules have a large capacitor from RST to ground. Charging this without current limit from GPIO16 is a problem. Connect GPIO16 to RST using a resistor. The value is not critical, a few hundred ohm to 1k is fine. That way the capacitor charges slowly and the reset works.

Some modules in addition need a pullup resistor on D3, otherwse the reset by GPIO16 will put them in Flash mode. I used 1k, that works reliably.

The ESP12Fs that I work with need both to reset reliably after timer expiration in deep sleep, without it only works sometimes.