Esp8266-uart dongle

esp8266-uart-dongle

A project for an esp8266 dongle for various IoT projects using UART.

Several manufacturers of home devices like air condition use a modified USB connector as so called WiFi-module to bring the devices into the manufacturer cloud. These dongles can be replaced by this project to control your device in your own cloud.

This project is inspired by https://github.com/dudanov/iot-uni-dongle

As there are no KiCad project files available, I had to rebuild it from scratch.

Other similar projects are:

• https://github.com/ezcGman/mideahvac-dongle

Main goals

Stay the same as in the original project from Dudanov:

• using popular WiFi-module ESP12-F based on ESP8266 SoC
• unified design for all types of home devices from different manufacturers
• support various connectors with a pitch of 2.54 mm and USB
• possibility of swapping the middle signal TX/RX contacts
• IR transmission and receiving via one wire connected to TSOP output
• very small design: PCB size 24.75 x 19 mm

I extended this with my own ideas:

• use components from JLCPCB Basic or Promotional library (except tantalum capacitors)
• use AMS1117 LDO
• use 0805 SMD components to allow hand soldering
• add reset pull-up and reset button
• add 100nF capacitor for ESP supply

SMT assembly at JLCPCB

The gerber directory contains the files necessary for manufacturing and assembling the board at the JLCPCB factory.

AMS1117 needs capacitors with an ESR >2 ohm, which most MLCC capacitors do not fulfill. Tantalum capacitors are not in JLCPCB Basic library, so you have to hand solder them yourself, pay the extra fee for Extended library or replace them by MLCC capacitors from Basic library on your own risk.

You may get a warning notice that the USB connector is not present, but that is intended as you have to solder that manually only when you need it.

Further steps are soldering the ESP module and selecting the TX/RX pin via solder jumpers.