The resistor values are as follows:

  • LED current limiting resistor = 1K
  • Pushbutton switch pullup resistor = 1K
  • Voltage divider resistors = 1K (top), 1.8K (bottom)
    You can connect FTDI TX to ESP RX directly if you have a 3.3V FTDI.

Source code is at:

https://github.com/hwiguna/g33k/tree/master/ArduinoProjects/2015/_Done/110-One_way_Chat