Comments on: ESP32 Deep Sleep with Arduino IDE and Wake Up Sources

By: Sara Santos

Sara Santos — Mon, 16 Jun 2025 16:04:33 +0000

In reply to WJCarpenter.

Hi
It is not necessary, but guarantees some stability.
Regards,
Sara

By: Sara Santos

Sara Santos — Mon, 16 Jun 2025 14:10:19 +0000

In reply to WJCarpenter.

Thanks for letting me know.
It is fixed now.
Regards,
Sara

By: WJCarpenter

WJCarpenter — Sat, 14 Jun 2025 17:17:01 +0000

In the descriptions of external wake-up sources, you disable pull-ups and enable pull-downs. In the breadboards, you show an external pull-down resistor. Is that external resistor actually necessary or just a sort of safety/insurance thing?

By: WJCarpenter

WJCarpenter — Sat, 14 Jun 2025 17:15:15 +0000

Good article. Very thorough and clear explanation of the various possibilities.

I thought I would alert you that there is some kind of editing glithc (fragments of sentences) in the section “External Wake Up (ext1)”.

By: Jules

Jules — Sun, 08 Jun 2025 04:51:03 +0000

In reply to Sara Santos.

Hi Sara,

so my problem is solved now. Problem is I was using getLocalTime(&timeinfo) without arg2 which is timeout ( default 5 seconds ). And it looks like it’s not enough at all ( + getLocalTime return true even no resync ntp has been done ).
So I switched to getLocalTime(&timeinfo, 15000), and I also add at every wake up :
– sntp_set_sync_mode(SNTP_SYNC_MODE_IMMED) ;
– sntp_set_sync_interval // 15 seconds
– sntp_set_time_sync_notification_cb( ntpSyncCallbak ); //log all ntp sync done + change sntp_set_sync_interval to 24h
– also put 2 ntp server names rather than just one.

Now my ESP posts datetime dont loose accuracy with the server datetime, I logged about 50 lines of datetime . ( time drift of esp in sleep mode still here (hardware ), but corrected by the ntp sync at wakeup ).

Regards,
Jules

By: Sara Santos

Sara Santos — Sat, 07 Jun 2025 17:28:55 +0000

In reply to Jules.

Hi.
That’s definitely not what is expected. Have you tried with another ESP32-CAM board?

REgards,
Sara

By: Jules

Jules — Sat, 07 Jun 2025 01:23:21 +0000

Hi Sara,
just to confirm, it does not solve the problem, still loosing 30 minutes / day even with a ntp sync at each restart.

By: jules

jules — Wed, 04 Jun 2025 05:36:03 +0000

In reply to Sara Santos.

Hi Sara,

I tried light sleep mode, but other problem rised. And so I ended up on an not elegant but easiest solution: simply fully restart the esp when it wakes up. So the time should be accurate on wake-up, it uses 2 boot ( wakeup boot + full restart ), but battery will be saved and time will be accurate, almost no code & no wiring. I wake up esp 2 minutes before they need to do their things, just in case. Still watching the logs to see if it solves this problem.

Regards,
Jules

By: Sara Santos

Sara Santos — Mon, 02 Jun 2025 09:27:15 +0000

In reply to Jules.

Hi.
Personally, I haven’t tried the clock of the ESP32-CAM yet.
I didn’t know it drifted so much.

Then, let us know if you succeed.
Regards,
Sara

By: Jules

Jules — Sun, 01 Jun 2025 10:44:46 +0000

In reply to Sara Santos.

Hi Sara,

thank you for your reply. Actually I’m looking for a solution without wiring anything more, fact is I printed boxes for the 3 cam, and if possible I would like to not redesign/reprint those boxes if possible. I still cant understand why these esp cannot give accurate time even with ntp resync at startup ( time drift error is cumulating ). I will have a look to other sleeps mode, or check the code of tomocchi3411, because some of my esp32 are powered by solar banks, and I just need 3 to 5 mesures every day.

Jules