The delivery was next day, and the price for the three of them was around 21 quid - about the same as I could find on AliExpress. They seemed particularly good value, especially as I got them using Prime.

I bought these as I was undertaking a project for my home automation set up. For just a small extra cost this solves the problem with little or no change to the source code.The only improvement I can think of would be a version akin to the D1 mini, where the surplus pins are removed and both sides of the board are used to result in a smaller module with no loss of facilities. See photo.Conclusion: I favour the 8266 in the guise of the D1 mini boards for most projects, but as soon as the project needs a bit extra, like more than one analogue input, or bluetooth, or just a bit of extra speed, that is when the ESP32 comes in. This results in plenty of access to the ESP32 pins with the added bonus of a central 2 wire-bus (ideal for I2C) running underneath. I can also see that it is not one of the nine touch-sensitive pins.For breadboarding, I have joined together two boards, but have removed the power bus from one of them. My sheet tells me that is pin 39, GPIO22, PWM is available, it is also the SCL pin for the default hardware I2C bus and the RTS pin for the first serial port. I keep a printed copy at hand as the print on the board is not only difficult to read, but nowhere near as informative as my printed crib sheet.For example, take the silk-screen pin IO22. 3.3 volt power and ground are available at the other end of the board.If you need an accurate pinout, just look up 38-pin Devkit-C on the Internet.

It is worth keeping away from this end of the board anyway as, apart from the 5V pin if needed, most of the IO pins are reserved for internal use to access the 4 megabyte flash memory. Despite all this, it is as easy to get beginner level code running (blinking LEDs, etc.) in the Arduino environment as it is for its little brother, the 8266, or any other board such as the Arduino Uno or Nano.There is an error in the silk-screen printing on the board where a pin is labelled 'GND' where it should be 'CMD'. The documentation on the manufacturer's site (Espressif) runs into thousands of pages (more than 800-page pdf hardware manual alone). Running at an impressive 240 MHz, it is no slouch, but it can also go into a deep sleep when extremely long life on battery power is needed. I can pretty much guarantee that no-one will actually use ALL of the capabilities.

This is a veritable powerhouse of a microcontroller board, with both WiFi and Bluetooth, plenty of RAM and flash memory, digital, analogue pins (and touch inputs), together with hardware features like random number generation, hall effect sensor, etc. Reviewed in the United Kingdom on 20 October 2020

The official esp32 book pdf