Sunday, December 30, 2018

Build your own IoT/MQTT node for less than $2

In this post, I will be explaining ESP-12F module usage with minimal set of components.
ESP-12F as a stand-alone module is of no use unless mounted on a base board like wemos-d1-mini.

This blog explains how to use ESP-12F module without the need of a base board but with minimal set of components.

Items needed(total cost of all the components is based on the prices from aliexpress)
1)1x ESP-12F module(pre programmed with tasmota firmware)
2)1x 10k SMD resistor
3)1x 10K thru-hole resistor.
4)2x 4001 SMD diode
5)1x USB male connector(PCB mount - smd).


Board Preperation Steps:
1)Ensure that ESP-12F module is programmed with tasmota firmware(here you can find the details on ESP-12F module programming)

2)mount 10k smd resistor between GND and IO15 pad of the ESP-12F module.

3)mount 10k thru-hole resistor between VCC and EN pad of the ESP-12F module.

4)Stick a piece of insulation tape on the right side of the ESP-12F module so that USB connector doesnt short any pads.
5)Place USB connector as shown below and smd pins of the USB connector shall be placed over the insulation tape.
6)on the backside of the board, fix the USB connector to the ESP-12F using hot-glue(dont apply hot glue on the smd pin side of the USB connector yet, this will be done at later stage)
7)solder two SMD diodes in series between Plus(+) line of the USB connector and VCC pad of the ESP-12F module.
8) Connect Minus(-) line of USB connecotr to the GND pad of ESP-12F module
9)Apply Hot glue on both the sides of the USB connector and ESP-12F for stability.

10)Power the board with 5v USB charger and look for open wifi ssid "sonoff-NNNN"
11)Follow the standard tasmota generic module configuration.


Anonymous said...

pretty cool!!!!!!!

Anonymous said...

Usb connector is just for power?
What about flash the firmware? Where is Flash and Reset button?

brna said...

You can buy node mcu or weemos d1 mini - both have USB-TTL and a nice brakeout board for esp8266

Walid Mafuj said...

Yes, buying wemos d1 mini is a clever idea.

Unknown said...


zoobab said...

Next step is to install esp-usb with D+ D- rails:

I took the picture with the breadboard :-)

Rogan Dawes said...

Very neatly done!

I did something similar to WiFi-enable my Current-Cost Envi R power meter.

My attempt

However, I had a very strange situation with repeatable corruption on the serial TX (from the ESP). It turned out to be ringing on the line, which was solved with a 10pF capacitor (blue).