In the summer holidays of 2016 I started a project to be able to operate a flashing light remotely with the ESP8266-01. It quickly became clear that programming with the help of a breadboard is quite annoying. So it’s easier to be able to program as a subproject to create a prototype board. I found the basis of this scheme on the internet (http://www.forward.com.au/pfod/ESP8266/GPIOpins/ESP8266_01_pin_magic.html).
The Tx and Rx are also used here as I2C interface. Nothing came of the flashing light, as quickly the project went a different way.
Version August 2016 (LJK1608)
After the first prototype board. I drawn the electronic schema and PCB via EasyEDA.com. I made some design mistakes, but good to experiment with. On the bottom side of the PCB, a TCN75A chip can be soldered (SMD).