This board was designed to drive multiple servo motors using a couple of low cost modules from china as well as
Espresiffs Dev-Kit C.
My Breakout module has 17 servo pins with 0v and V servo connectors 3 I2C connectors with pull ups note that all 3 I2C connectors are connected in parallel, Uart 0 is brought out to a 3 pin connector RX TX and 0V there are 2 analogue inputs these are connected to the Svn and Svp through a potential divider in my case i have this set to allow for a 5v input the analogue inputs have 2 clamping diodes to stop voltage above 3v3 reaching the pins there is also a position for a soothing cap on the input i have 2u2 fitted to mine. Lastly there are 3 5v pins and 3 0v pins as you never find one when you need it.
The break board shown left has a low cost Geekcreit ESP32-Devkit module fitted which was a little over £5 ($7) this module has 4MB spi flash and performs fairly closely to the Dev-Kit C the biggest difference was the USB would not upload at any speed above 115200 Baud probably because its using the CH340 Uart-Usb chip. This module breaks out all the pins Wroom. As mentioned already the breakout board will also take Espresiffs Dev-Kit C just plug it into the sockets marked Dev-Kit C on the silk screen i got my Dev-kit C from amazon as seemed to be the cheapest it also came with rev 1 silicon although to be honest as long as you read the errata on the rev 0 and implement the fixes or avoid those with no fix you should be OK in my case controlling servos i notice no difference between them. The last module will fit breakout board is another geekcreit board again £5 on offer when i brought but about £7 when not, it does seem to be on offer most of time this one is slightly different as it does not bring out the spi flash or sd card pins no problem for this application as neither does the breakout board it functions as well as the other two and you can upload at full speed as it has CP2120 Uart-Usb that is the same one used on Espressifs Dev-Kit C, although its marketed as Geekcreit it is actually a doit.am board and has Luanode software available it is also the only one of the three that has a user led fitted so blinky works straight of the box.
the Geekcreit or doit ESP32 Node MCU is shown left it has 2 rows of 15 pin headers compared to the 18 on the Dev-Kit C and 20 on the red Geekcreit ESP32 Dev-Kit. There are many modules out there that have very simular foot prints to these 3 boards but check the pinouts and dimensions before trying with other boards below are the pin count they are all 0.1" 2.54mm pitch pin count.
Espressifs DEV-KIT C has 19 Pins 2 rows which are 25.15mm Apart. So does the GOOUUU ESP32 Board.
The GeekWorm Easy Kit has 20 Pins 2 rows which are 27.50mm Apart.
DOIT DEV KIT V1 has 15 Pins 2 rows which are 25.25mm Apart. If you are going to use a differant board please double check that it pin out matches one of these.