I'm Trying to put to deepsleep a Wemos mini/ NodeMCU / ESP-01, and facing the same problem - fail to wake up.

Looking around - I've found some articles such this github issue, and this issuedescribing same behavior of not waking up as expected.

code as posted in first github issue, which is very simple:

void setup() {
  while (!Serial) { }
  Serial.println("Going to sleep.");

void loop() { }

Hardware setup: pins connected: RST + D0

But at the end - I found no solution but saying that "some of chips/ boards fail to wake up".

Since all my boards at hand fail, I don't know if is if the formal answer for that phenomena.

Any assistance will be appreciated,

  • 1
    \$\begingroup\$ esp-01 doesn't have io 16 accessible, so you can't wake it up from deep sleep. esp8266 pin io 16 (D0 on NodeMcu and WemodD1 mini) is connected to inernal RTC of the esp8266, which doesn't sleep and counts down the sleep time. to wake up the esp the RTC connects io 16 to ground. if the reset pin has an external pull-up resistor with low resistance, the io 16 can't pull it down to reset. \$\endgroup\$
    – Juraj
    Commented Dec 17, 2019 at 10:28
  • \$\begingroup\$ @Juraj thank you for your comment. First, I don't use ESP-01, but Wemos and NodeMCU, which GPIO16 is not accessible. Second, since boards used in tutorials ( same models as I did try ), can accomplish waking up, I try to understand who or what is wrong my with boards, and how can I check it/ fix/ buy others ? \$\endgroup\$
    – guyd
    Commented Dec 17, 2019 at 17:50

1 Answer 1


My assumption was right.

Some of the boards wake up as expected and some not, same kind, same code( probably different seller ). I guess i t has something to do with hardware as explained in link in my question.


  • \$\begingroup\$ This is really interesting. I have problems with a Wemos board not waking up after longer sleep periods (i.e. one hour) but waking up just fine for shorter periods (10min) \$\endgroup\$
    – Dennis G
    Commented Aug 11, 2022 at 13:25
  • \$\begingroup\$ @DennisG same thing was with WEMOS as well. Those who are ment to be sleep/awake systems, I check and mark them in advance ( Bad solution, but the minimum I can do) \$\endgroup\$
    – guyd
    Commented Aug 11, 2022 at 19:34

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