ESP8266 Breakout Board

Description

This board is a simple, small board that breaks out various bits of I/O from the ESP-12e (or ESP-12f) module, combining the GPIO pins with plenty of power pins. The goal is to design a simple platform that is directly connectable to devices and sensors with no need for extra wiring/soldering/components to split off power, etc.

The other goal for the board is to be cheap and small.

Details

The breakout board has various bits and pieces on it. The stuff that's important to you would be the power regulator, the pin headers, and the two optional solder bridges.

First off is the pinout. For power/serial/SPI/ADC/reset this is pretty clear - every pin for these is silkscreened. For the four GPIO pins that are broken out, it's a bit less clear as I didn't have enough silkscreen room for every pin. Each GPIO pin is labelled with its NodeMCU pin #, as well as the raw GPIO pin number. To each side of the GPIO pin is a power pin. These power pins are tied to VIN, and not VCC, so keep that in mind. Two of the GPIO pins can be used as I2C, and all four of them have PWM capability.

Second, the solder bridges. There are two.

The DPSLP bridge ties D0/GPIO16 to the RESET pin. This allows the ESP8266 to wake itself up from deep sleep via the RTC module. Keep in mind this means that you cannot use this GPIO pin for anything else!
The VCC=VIN bridge bypasses the NCP114 linear regulator. If you supply the board with 3.3v, then you don't need a regulator and you can just bridge this. I would still recommend using at least one of the two capacitors in order to maintain good power quality.

The NCP114 regulator is not meant to provide power to peripheral devices. It is sized to comfortably power the ESP8266.

The FLASH and RESET tactile switches are positioned and sized so that they are reasonably possible to press with a single thumb, or with both index fingers if you hold the breakout board with the antenna pointing at your head, ESP facing toward your chest.

Files

Board.sch

EAGLE Schematic

sch - 312.74 kB - 01/24/2018 at 19:16

Download

Board.brd

EAGLE Board Layout

brd - 91.89 kB - 01/24/2018 at 19:16

Download

Components

1 × ESP-12f

1 × NCP114 3.3v regulator

4 × 10k Resistor Pullups/Pulldowns for config and reset

2 × Capacitor Power capacitors to stabilize supply

2 × Tactile Switch KMR4-series tactile switch

Project Logs

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Ongoing Progress

Sukasa • 08/18/2018 at 16:24 • 0 comments

Wow, 7 months. Need to update more.

In that time there have been a few updates. A pair of swapped pins on the original footprint, optimized/cleaned-ipup layout, and the addition of three resistors to the ADC pin means the breakout is far more robust than before. I have been using it for a few network sensors around the apartment now and am quite satisfied with the revised design.

All that remains is to do some final cleanup and documentation in the EAGLE design and post it.

First Prototype

Sukasa • 01/24/2018 at 19:06 • 0 comments

The first prototype PCBs came in last week, and the parts came in yesterday. So of course I get my stuff together and I solder one up (note to self: get a proper soldering iron).

Worked.. not great. Turns out, GPIO15 should be tied to ground and not VCC. Whoops. Thankfully fixing that in the prototype was as easy as desoldering one of the 10k resistors and shorting GPIO15 to ground with a solder bridge. Already got the schematic and board corrected for the next run on this board.

Not sure I like the ADC pin on the board. Might try to fit in some unpopulated resistor pads to make it more flexible.

Discussions