Arduino/C++ ESP32 Lessons

This video covers the differences between the Arduino analogRead() and the ESP32 analogRead().

Although the function is used in exactly the same way the outputs are different due to the ESP32 having a 12 bit ADC rather than the 10 bit version of the Arduino Uno.

This video also covers the issues around using the ESP32 wifi functions alongside the ADC functions.

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Lesson circuit diagram, click image for larger version

Arduino analogRead() lesson

Other information:

ESP32 Pin Out Diagram This page as Last Minute Engineers is a great resource for the various pinouts of the ESP32 Dev Module

This video covers how to use the I2C 1602 Liquid Crystal Display with the ESP32.

As the I2C 1602A Display requires 5v to work a level shifter needs to be placed between the I2C 1602A and the ESP32 to prevent 5v signals being sent from the I2C 1602 dislay to the ESP32.

I have concered the use of the 1602A screen in a seperate lesson with the Arduino Uno.

The code works in the same way so for more information see:
Arduino 1602A I2C LCD Screen

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Lesson circuit diagram, click image for larger version

Other information:

ESP32 Pin Out Diagram This page as Last Minute Engineers is a great resource for the various pinouts of the ESP32 Dev Module

Click to download resources for Video

This video shows how to set up and use ESP-NOW in Broadcast Mode.

ESP-NOW Broadcast mode allows almost limitless numbers of ESP32's to communicate but also has some issues that need to be thought about to make a smooth running system.

Expressif ESP-NOW documentation

For information on using FIFO (circular) buffers see:

https://www.digitaltown.co.uk/howtoFIFO.php

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This video follows on from the ESP-NOW Broadcast Mode video.
Starting with the final sketch of that lesson this video continues with how to apply simple encryption to protect your system ID number.

Expressif ESP-NOW documentation

For information on using FIFO (circular) buffers see:

https://www.digitaltown.co.uk/howtoFIFO.php

In 2024 Expressif updated the libraries that the ESP32 board library was based on.

This meant that ESP32 board libraries 3.0.0 and greater have certain changes of functions that will break code written on pre version 3 libraries.

Sadly this means that onlne tutorials written on the old board managers suddenly doesn't work.

This video deals with the error message caused by the line:

esp_now_register_recv_cb(OnDataRecv);

Producing the error:

Compilation error: invalid conversion from 'void (*)(const uint8_t*, const uint8_t*, int)' {aka 'void (*)(const unsigned char*, const unsigned char*, int)'} to 'esp_now_recv_cb_t' {aka 'void (*)(const esp_now_recv_info*, const unsigned char*, int)'} [-fpermissive]

As I have come across these issues I have created short videos to explain the changes that need to be made to your code.

This video looks at changes to certain wifi features linked to ESP-NOW

Click to download resources for Video

In 2024 Expressif updated the libraries that the ESP32 board library was based on.

This meant that ESP32 board libraries 3.0.0 and greater have certain changes of functions that will break code written on pre version 3 libraries.

Sadly this means that onlne tutorials written on the old board managers suddenly doesn't work.

As I have come across these issues I have created short videos to explain the changes that need to be made to your code.

This video looks at changes to certain wifi features linked to setting a custom MAC address

Click to download resources for Video