ESP8266 - WiFi µC

ESP8266: Cheap WiFi chip, meant to be connected to other microcontrollers (e.g. Arduino) via UART.

Specs

• 32-bit CPU, 80MHz
• 64KBytes of instruction RAM
• 96KBytes of data RAM
• 64KBytes boot ROM
• Flash: 4Mbit (512KByte)
• VCC: 3,3V
• 802.11 b/g/n
• Controlled via AT commands (default firmware)
• Microcontroller can be used directly
• So far IPv4 only

Modules

• ESP8266 available on a number of different modules
• Overview: http://www.esp8266.com/wiki/doku.php?id=esp8266-module-family or http://blog.thomasheldt.de/esp8266-module-uebersicht/
• ESP-01: cheapest, only 2 GPIOs available (+ Serial). 2x4 2.54mm pin header
• ESP-07: external antenna connector + chip antenna. 2.0mm SMD headers on both sides
  • Breadboard adapters on eBay (cheap), or:
    • Basic, but w/ reset and flash buttons: http://www.electrodragon.com/product/esp8266-smd-adapter-board/
    • Advanced: https://www.tindie.com/products/Ba0sh1/esp8266-esp-0712-full-io-breadboard-adapter/
    • Breakoutboard with circuit diagram: https://learn.adafruit.com/adafruit-huzzah-esp8266-breakout/downloads
• ESP-12: similar to ESP-07, but w/o antenna connector, instead just PCB trace antenna
• NodeMCU board:
  • Devboard
  • Includes ESP12 and USB<->Serial-Chip
  • http://www.esp8266.com/wiki/doku.php?id=nodemcu
  • Sources & Pinout: https://github.com/nodemcu/nodemcu-devkit
  • http://www.electrodragon.com/product/esp8266-nodemcu-development-board/
  • USB<-> Serial Chip of v0.9 not supported under OS X out of the box. Fix: http://kiguino.moos.io/2014/12/31/how-to-use-arduino-nano-mini-pro-with-CH340G-on-mac-osx-yosemite.html

IDE

• Support for Arduino IDE: https://github.com/esp8266/Arduino
  • Issue Tracker: https://github.com/esp8266/Arduino/issues/
  • Flashing not working in OS X. Fix: https://github.com/esp8266/Arduino/issues/3#issuecomment-87601656
  • Lot of standard libs supported

Project Ideas

• WiFi connected sensors
  • Temperature monitoring at home, datacenter, …
  • Plants
  • Motion detection
  • Automatic upload for dataloggers -> as moving devices come towards known hotspots (-> Freifunk?)
• Home automation
  • Switches, Relais, …
  • Heating, AC
  • Appliances
• Status lamps
  • LEDs
  • WS8211 RGB LEDs
• Serial Terminal
  • connect to PC or else, replacement for USB<->Serial connector
  • Telnet -> Serial
• DMX Artnet Node
  • Even cheaper than http://www.dmxcontrol.de/wiki/Art-Net-Node_f%C3%BCr_25_Euro ?
  • Already built by Ulrich Radig: http://www.ulrichradig.de/home/index.php/dmx/wlan-art-net-node
• Open WiFi finder, similar to https://learn.adafruit.com/wifi-hotspot-finder-adafruit-pro-trinket-cc3000
• General Purpose µC
  • Cheaper than most Arduino boards, yet more power
  • Even when no WiFi is needed

Issues & open questions

• Power management
  • Battery Power?
  • Power supplies
  • Sleep modes are available
• IPv6?

Further resources

• http://www.mikrocontroller.net/articles/ESP8266
• http://makezine.com/2015/04/01/designing-breadboard-adaptor-5-esp8266-microcontroller/
• http://makezine.com/2015/04/01/installing-building-arduino-sketch-5-microcontroller/

Changelog

• 2015-05-15: More information on NodeMCU and ArtNet node. WiFi finder “idea”.
• 2015-05-17: Link to Adafruit’s break out board circuit diagrams