In my previous attempt at designing this board here. It was good. But to make the pcb smaller. I redesigned the pcb, i shifted some component here and there.
This PCB contains a 3.3v level shifter at the receiver pin.
Here are the schematics and pcb layout.
Etching time : 1 hour and 20 minutes
That’s very long time but the solution is used up. as this is a small board i don’t want to dip the board in new solution. Also i let the PCB sit for a while , and by doing this the etching is uniform and the i also found out that the traces are much sharper than before. So it is a good idea to let it sit for around 30 minutes before you shake the container. As i am doing this manually, so that is why it is a slow process.
Esp8266 runs on 3.3V and most microcontrollers run on 5v . The voltage difference can cause problems in communication or in the worst case it can burnout the esp8266. So to address this probelm i created this simple interfacing pcb.