Hi.
If you use the ESP32 as an access point, it creates its own Wi-Fi network. You can connect to it using your smartphone as long as your board and smartphone are relatively close.
You can access the data in remote locations without internet. You can build a web page in access point mode that allows you to download the data. For example, take a look at this tutorial (you would need to modify it to use access point): https://randomnerdtutorials.com/esp32-datalogger-download-data-file/

I hope this helps.

If you have more questions, you can use our contact form: https://randomnerdtutorials.com/support/

Regards,
Sara

Please forgive my naive questions–I’m new to Arduino and ESP32. I built an ESP32-C3 altimeter from another website, but it did not work.

Your design is better for me anyway. I plan to build a compact, sensitive altimeter with data logging for cave survey applications, not hiking or airplanes. I’m looking for maybe ±0.4 m precision, using spreadsheet analysis of sampling data after each trip.

Is the “ESP32 access point” an internet web page, or something internal to a cell phone with wf or bt connection to the ESP? I need to do this in remote locations with no internet. Perhaps I can just input the pressure into the sketch and go without cell phone and networks.

I have 4 more questions. Would it be OK to post them here, or do you want to talk by email?

Thanks,
Bill Elliott
speodesmus at gmail.com

That’s great!
Thanks for those suggestions.
Regards,
Sara

Sara,
I used a Ravpower 20000 mAh cell phone power bank with a USB outlet.
Thanks for all you do,
Jim

Hi Jim.
That’s great! Thanks for sharing your experience with the sensor.
This seems one of the best sensors to estimate altitude.
Regards,
Sara

Hi.
We had a great time!
We used a portable charger (power bank).
Regards,
Sara