ESP8266 with NodeMcu

NodeMCU is Lua based firmware for ESP8266. Long story short - instead of writing in C you are able to use Lua which allows for faster prototyping (at least in theory!).

Pre-requisites

Hardware

  • ESP8266 - Olimex MOD-WIFI-ESP8266-DEV is best for development - fits on breadboard and leaves 2 rows of pins, while the NodeMcu Development Kit featuring integrated serial to usb cover a whole breadboard and you need to use jump wires instead of dupont wires. The other modules suitable for development are ESP-7, ESP-8 and ESP-12, but they don’t fit on standard breadboard so you want to order some adapter plates.
  • USB-UART cable - any serial cable should do, but there are some modules with integrated 3V3 power supply
  • Power supply - it’s best to obtain a combined 3.3V and 5V power supply as some components require 5V.
  • AC-DC adapter or USB cable - 5V@500mA or better, preferably 9V@1A. The ESP itself consumes up to 300mA so make sure you have enough supply or you will experience very strange behavior from the ESP.
  • Breadboard - any size will suffice
  • Dupont wires or Jump wires - mostly male-to-male, but some male-to-female should be available
  • [OPT] Logic Level Converter - the more channels the better and definitely two-way
  • [OPT] Switch buttons - just to ease entering flash mode and restart. The NodeMcu DevKit has those integrated

Software

  • Text editor - anyone (except Notepad due to it’s notorious BOM). I’m big fan on Atom IDE so you may give it a try.
  • Serial Terminal - PuTTY for win, picocom available in dep repos, mac - ???
  • luatool - for loading lua files
  • esptool - for burning images
  • NodeMCU - just take the latest build

Setting up

Get the Fritzing file

The most important things to wire are (for Olimex module):

  1. Pin 1: 3.3V - power supply +3.3V
  2. Pin 2: GND - power supply GND
  3. Pin 3: GPIO1 - connect to UART TX
  4. Pin 4: GPIO3 - connect to UART RX

On ESP-7,-8 and -12 you need to connect

  1. Pin 3: CH_PD - power supply +3.3V
  2. Pin 8: VCC - power supply +3.3V
  3. Pin 9: GND - power supply GND
  4. Pin 15: RXD - connect to UART TX
  5. Pin 16: TXD - connect to UART RX

Flashing NodeMcu

  1. Download the latest release. Integer version seems more stable for the moment.
  2. Connect GPIO0 (pin 21 on Olimex module) to power supply GND to enter flash mode
  3. Power on or restart the ESP module

  4. Flash the downloaded firmware

    1
    esptool.py write_flash 0x00000 nodemcu_integer_0.9.6-dev_20150331.bin

  5. Start your terminal at baudrate 9600bps

    1
    picocom -b 9600 /dev/ttyUSB0

  6. Hit Enter

  7. You should see the lua prompt
    1
    >

Now you’re ready to start develop.

Useful resources