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I am using a NodeMCU v.1.0 ESP-12 for a small project. It is powered by 3xAA batteries (4.5v) in Vin, but to reduce power consumption I need to put in in deepsleep every now and then.

Running this small sketch:

void setup() {
  Serial.begin(115200);
  Serial.setTimeout(2000);

  // Wait for serial to initialize.
  while(!Serial) { }

  Serial.println("I'm awake.");

  Serial.println("Going into deep sleep for 20 seconds");
  ESP.deepSleep(20e6); // 20e6 is 20 seconds
}

void loop() {
}

I have measured a consumption of 8mA when it goes to deepsleep, and this is not acceptable for my purpose. In order to wake up from sleep I have connected pin GPIO16 (D0) to RST, and it works. I knew that NodeMCU should have only few µA of consumption in deepsleep. How can I fix this?

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  • Have you tried to remove the LED?
    – MatsK
    Jul 25 '18 at 13:30
  • Which one? The board has just a tiny blu LED which flashes for a moment when you switch it on, then it turns off. No LEDs are on during operations. Jul 25 '18 at 13:34
  • 1
    Sorry forget the LED! Look at the LDO, look at this electronics.stackexchange.com/questions/286249/…
    – MatsK
    Jul 25 '18 at 13:37
  • I will read that link, thanks. But I have also made a test powering it directly on the 3V3 pin by an external regulator and the results are the same. Jul 25 '18 at 14:11
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    how much is used by the usb serial that you don't need after flashing?
    – dandavis
    Jul 25 '18 at 19:07
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Consider the TI TPL5110 timer chip with power control MOSFET. Set the timer period with a resistor then the TPL5110 powers on the NodeMCU periodically. Deep sleep is not used. RTC RAM will be lost so use SPIFFS for persistent data.

Adafruit has a breakout board. Take a look in Adafruit's forum for user comments because it has a few limitations.

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  • You worried me about your warning "look at comments..", but I can't find anything serious... Jul 30 '18 at 10:37

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