The ESP-12E is an awesome low-power WiFi-capable module with an ESP8266 inside. it also supports deep sleep and so can run on batteries for a super long time. I grabbed some of these modules from DigiKey and was sad to learn that I couldn’t just solder some legs on it and get to testing it out.

Unfortunately for prototypers and tinkerers alike, the footprint of the module doesn’t lend itself well to experimenting with ideas on (for example) solderless breadboards.

The pitch (distance between pins) on the module is 2mm, whereas breadboards, perfboard, veroboard, stripboard etc use 2.54mm.

My first pass at getting something going was this lovecraftian horror:

The ESP-12E suspended above a breadboard by some crudely soldered-on wires.
We can probably do better than this

KiCAD to the rescue

After spending a lot of time on YouTube learning about PCB designs, I ended up with this design:

PCB for the breakout board as seen inside KiCAD
I tried to make it as symmetrical as possible

The idea was to maximize the amount of breadboard holes you can access on either side of the pins, which is why I ended up going with this strange sort of elongated snake arrangement. I tried to apply what I had learned and used thicker traces for the 3v3 and GND lines as well short traces leading to the vias underneath the module itself.

After exporting the Gerber files from KiCAD I submitted them to JLCPCB and waited. A few days later, I got 5 of these in the mail:

Populated PCB
Excuse the gnarly soldering job!

Next thing to do is plug it into a breadboard and get it powered up!

You can pull various pins up or down to control the way in which the module boots:


TL;DR: You just change GPIO0 from HIGH to LOW when you want to program it.

Here’s some example circuits using the module. The left one always just boots normally. The right one incorporates some buttons so you can reset the module into Download Mode by holding the BOOT button and tapping RESET.

Circuits to boot the ESP-12E

Get the breakout boards

If you want some of the breakout boards yourself, you can download the KiCAD project from Github here: