Wire it up as shown with a 4.7k pull-up on DS18B20's signal pin. I used a wall wart for power, but you can use whatever, maybe add a large capacitor if your power supply is weak. Be sure to wire cathode from LED to GPIO0 otherwise it will act as a pull-down and send esp to bootloader mode. You can also put a relay instead of LED since this is a lightswitch after all.

Grab the files from git and cd into "ESP_Code". Be sure your usb to UART is 3.3v and hook it up to tx n rx pins on ESP. Pull GPIO0 low and reset to send it to bootloader.

Run:

$ make

$ make flash

Partway through make flash it will say sleep 3. Use this time to reset your esp or it will exit bootloader and will not flash completely. Then reset it again before running:

$ make htmlflash

With UART still connected to PC watch minicom or other serial terminal and then reset chip with GPIO0 floating or pulled high to exit bootloader mode. Output should tell you what ip address it has. Then you can open a browser and type in that ip to see user interface. If esp has never connecteed to your home's wifi then it will become a wifi AP itself. If that's the case you need to connect to it's nnetwork and go to 192.168.4.1/wifi.html to connect to your home's AP.

Be sure to write me a comment or send a message if you have issues. Otherwise profit!