ESP8266 Introduction

esp8266_intro.md

#Overview

The ESP8266 is a versatile chipset that provides client and access point wifi capabilities, on-chip SRAM and flash storage, a RISC processor, GPIO pins, and pin outs for memory and CPU extensability. Bundled as a series of modules with varying features focused around acting as either a wifi extension module to an existing microcontroller or as an self-contained solution for integrating wifi and internet functionality with GPIO control. From an application standpoint, the ESP weighs in as an inexpensive and compact alternative to AVR (arduino) based, wifi-driven IoT solutions.

Chip Layout

AT Command Set

AT+RST restart the module, received some strange data, and "ready"

AT+CWMODE=3 change the working mode to 3, AP+STA, only use the most versatile mode 3 (AT+RST may be necessary when this is done.) Join Router

AT+CWLAP search available wifi spot

AT+CWJAP=“you ssid”, “password” join my mercury router spot

AT+CWJAP=? check if connected successfully, or use AT+CWJAP?

• Documentation: https://drive.google.com/folderview?id=0BwK3EhAfht8uWTdBdG55NEFCakE&usp=drive_web
• Python AT Command Tests: https://github.com/guyz/pyesp8266

Devices

ESP-01

• Design:
• Wifi Features:
  • 802.11 b/g/n
  • 19.5dBm output in b mode
  • WPA/WPA2 security
  • Client Mode / Access Point Mode
• Pin Layout:
  • UTXD: Serial Transmit
  • GND: Ground
  • CH_PD: CH Pull Down
  • GPIO2: GPIO register
  • RST: Reset
  • GPIO0: GPIO register
  • VCC: 3.3v Power IN
  • URXD: Serial Receive

• Pin Pullup/Pulldown Modes
  • Normal Mode:
    • Pull-UP CH_PD (Connect CH_PD to VCC)
  • Write Mode:
    • Pull-DOWN GPIO0 (Connect GPIO0 to GND)
• Power:
  • 3.3v VCC IN. 3.6v TOLERANT
  • Not very tolerant - make sure to use voltage regulator
  • Power consumption: http://blog.hekkers.net/2015/03/20/esp8266-current-power-usage-charts/
• LEDs
  • Red LED: Remains on when power applied
  • Blue LED: Blinks when flashing, blinks once during reset
• Memory/CPU Limitations
• Breadboard Adapters
  • Adapter: https://www.tindie.com/products/rajbex/esp8266-breadboard-adapter/
  • DIY: http://www.instructables.com/id/DIY-Breadboard-Adapter-for-ESP8266-WiFi-module/
• Notes Writing Firmware:
  • After pulling down CH_PD pin, you Enabling Deep Sleep on the ESP-01: http://tim.jagenberg.info/2015/01/18/low-power-esp8266/

ESP-12e

• Design
• Wifi Features
  • 802.11 b/g/n
  • 19.5dBm output in b mode
  • WPA/WPA2 security
  • Client Mode / Access Point Mode
• Pin Layout

• Pin Pullup/Pulldown Modes
  • Normal Mode:
    • Pull-UP CH_PD (Connect CH_PD to VCC)
  • Write Mode:
    • Pull-DOWN GPIO0 (Connect GPIO0 to GND)
• Power
• Memory/CPU Limitations
• Breadboard Adapters
  • Adapter: https://www.tindie.com/products/Ba0sh1/esp8266-esp-0712-full-io-breadboard-adapter/
  • DIY: http://www.instructables.com/id/Getting-Started-with-the-ESP8266-ESP-12/
• Notes

ESP-13wroom

• Pin Layout
• Notes

ESP-14

• Pin Layout

• Notes

Development Boards

####Nodemcu devkit v1.0

Write latest firmware. Use integer release, pre-dev version, include '-fm dio -fs 32m' for valid flash. Default baud rate should be 9600 or 115200. Writing firmware using esptool:

./esptool.py -p /dev/tty.SLAB_USBtoUART write_flash -fm dio -fs 32m -ff 40m 0x00000 nodemcu_integer_0.9.5_20150318.bin

Electrodragon's Nodemcu devkit tutorial: TUTORIAL

Platforms:

NodeMCU

• Flashing Firmware
• Example Code

Arduino for ESP8266

• Flashing Firmware
• Example Code

AT firmware

ESP8266 Espressif SDK (C++)

Micropython

Frankenstein

References:

• http://blog.squix.ch/2015/03/esp8266-module-comparison-esp-01-esp-05.html

Talking with the Web

• Cloud:
  • MQTT Cloud Broker: https://www.cloudmqtt.com/
  • ThingSpeak: https://thingspeak.com/
  • Firebase

GPIO