This is a board designed to take a WeMos D1 Mini board(with the ESP module removed) and use it as a USB interface with built-in reset/flash functionality for bare ESP8266 modules similar to the ESP-12 units.

The PCB was drawn up in Eagle and I have successfully gotten them manufactured through OshPark.

They are designed to be used with Pogo pins. I STRONGLY recommend the mushroom head type.

The D1 Mini board is to be mated to the PCB in a manner similar to ball grid array: add solder to the pads where the ESP module was to give it a bump.

Rest the board on the PCB within the outline with the bumps facing their matching set of pads and heat from below with a hot air gun. When the solder melts, the boards will come together. Presuming no bridges, you should be good to go.

• Don't install the pogo pins too far in. Otherwise, you'll never get the ESP module installed.
• Don't get flux or solder onto the pin portion of the pogo pin... this will ruin them.
• Don't use low temp solder paste... tried this route and was a PITA.
• You can solder the pogo pins individually... but I had the best luck with 2 runs of solder paste on the end away from the pin side and placing the pins in place and using hot air to reflow the solder. This works great.