Comments on: ESP32: Wake-Up From Deep Sleep using External Alarms (DS3231 RTC)

By: Sara Santos

Sara Santos — Wed, 19 Mar 2025 15:17:38 +0000

In reply to Amadou.

Yes. But, waking up the ESP8266 from sleep using an external wake-up is different.
Check this tutorial: https://randomnerdtutorials.com/esp8266-deep-sleep-with-arduino-ide/
Check the section called #2 ESP8266 Deep Sleep with External Wake Up

Regards,
Sara

By: Amadou

Amadou — Wed, 19 Mar 2025 15:09:59 +0000

Hi. Is it possible to do this on esp8266 wemos d1 mini? If so what changes do i need to make. Thanks

By: Joaquín Mendes Castro

Joaquín Mendes Castro — Sun, 16 Mar 2025 18:24:53 +0000

Hi
I am working on a project with a LILYGO-T-SIM-A7670E board. I would like to wake it up from deep sleep when the modem receives data. I don’t even know if the modem is alive when the processor is in deep sleep mode so it may be an impossible task. In my code, I set a TCP connection to a server via tcpclient.connect(server, port). I would like to wake up the ESP32 when the server sends some data through this TCP link. Does it even make sense? How could I do it? Would it be easier when receiving an SMS message?
Thank you so much for your tutorials and help.

By: Sara Santos

Sara Santos — Sat, 15 Mar 2025 10:48:06 +0000

In reply to Marek.

Hi.
You’re right.
Thanks for letting me know. I’ll fix the code.

I’m glad you like Portugal. You also need to go to Feast of St John in Porto, approximately 10 days after the St.Anthony.

Regards,
Sara

By: Marek

Marek — Fri, 14 Mar 2025 21:04:02 +0000

Hello. This is my first post on this site. Sorry for the language problems but my English is very poor. I have a question, shouldn’t the interrupt function be declared as void IRAM_ATTR onAlarm() ??. And I want to say here that I really like Portugal. I’ve been to Lisbon 10 times. I always go there for the Feast of St. Anthony and I live there for 14 days. That’s 5 months of my stay. It’s always great.
Greetings from Poland

By: Philippe

Philippe — Thu, 13 Mar 2025 23:55:06 +0000

Hello,

I am using an ESP32 that does WIFI + connection to MQTT server + send Temperature data and then does a deep sleep for 1 minute. The ESP32 is on sector (the future version it will work on battery). This code works randomly for 5 hours to 10 days. And then the ESP32 does not wake up. Some other user seems to have the same problem.
How long have you test the wakeup via external signal (not internal clock).
Have you some pointers to solve this problem ?

By: Ed

Ed — Thu, 13 Mar 2025 21:10:26 +0000

I have used this on an ESP8266-01 for the simple reason that pin 16 is not easily available on that module. On an ESP32 I do not see much advantage, but it indeed does illustrate a possibility

By: Ed Hayes

Ed Hayes — Thu, 13 Mar 2025 20:12:29 +0000

I’m trying to think of the benefit of using this rather than the build in wake timer. Is it so that you can set an actual time to wake up rather than in X number of MS?

It seems the deep sleep power consumption of ESP32 is less than that of the DS3231.

By: richo

richo — Thu, 13 Mar 2025 17:52:32 +0000

I would like a tutorial on how to get ext xtal 32K working on esp32 using arduino IDE