Dear Rui and Sara,
I purchased both LVGL and Learn ESP32 eBooks and I think they’re great!
I have some suggestions on topics to include in the LVGL eBook.

1. Add preferences.h discussion from Module 3 in Learn ESP32
Re-write Module 3 in ‘Learn ESP32’ specifically for LVGL/CYD where preferences.h saves:
SSID, password
touchscreen coefficients
openweather api-key
adafruit_io username, password
things network username, password
etc.
I really don’t want to ‘sanitize’ my code (taking out my WiFi password or private api keys) every time I send my code to friends.

2. cover the usage of the built-in microSD card reader (copy Module 3 from ‘Learn ESP32’)
Add a new ‘Picture Frame’ tutorial.

Not covered in either book:

3. how to save compiled programs to littlefs / how to run pre-compiled programs from littlefs?
For example:
At 9pm, run a clock program to display time (and use as a night light)
At sunrise, run a weather program with readings from openweather and local sensors.
When solar cell open-circuit voltage rises above 5.3 volts, start a battery health and charge program…

4. with respect to sensors and specifically in LVGL Module 4.2, extend the example with a brief explanation and implementation of hysteresis as applied to both heating and cooling control.

5. With respect to ‘Learn ESP32’, add a project:
I want to track where my dog is on my property (approximately 120 square km).
I would like to do this using a GPS module and LoRa.
I would like to track her in real time using google maps (or similar web-based mapping solution).
I want to use the same setup with my 8-year old kid for Halloween trick or treat!

I’ve learned quite a bit with your tutorials. I look forward to your latest tutorials and will support you by buying more eBooks!
Thank you for listening!
-a.c.