ESP8266

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This is a collection of resources for software/hardware/firmware development on/with an ESP8266.

Basics

Choice pieces of information

  • The module nominally runs on 3.0-3.6V. In practice, it tends to boot just fine as low as 2.5V, and 4.7V is the absolute maximum. Source
    • This means you can probably get away with running an ESP8266 directly off of a single Li-ion/Li-poly cell. More information on Li-ion battery voltages
    • The often-repeated information stands: This is not a 5V device. If you run it off of 5V, you will smoke it within a few seconds.
    • Check out this voltage regulator for battery and/or 5V powered applications.
  • According to the datasheet, the module "typically" can draw up to 170mA (whatever that means). In practice, your supply needs to be able to provide at least 300mA.
    • This is really just information that "is known". You can see references to it here. I (User:hfuller) have personally measured 240mA, and I don't even have a fast meter, so I'm likely missing any spikes in draw due to Wi-Fi transmission or whatever.
  • You have to have certain pins in certain states in order to boot your code, run the boot loader, etc. See Figure 1.
Figure 1

Power saving

  • Use deep sleep to save power when you don't need to be running for a long time.
    • Docs for Arduino IDE here.
      • Something unclear: deepSleep with time of 0 sleeps forever.
    • "GPIO16 needs to be tied to RST to wake from deepSleep."
    • Datasheet claims 60 microamps in this state. Realistic results with testing here.
    • You can wake up several different ways; there are settings to tweak RF calibration and other stuff. Measurements here.

Random resources

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