Section 7.1 of this Espressif datasheet provides data on current consumption. These data are based on 3.3V supply, and 25C ambient, using internal regulators. Measurements are done at antenna port without SAW filter. All the transmitter’s measurements are based on 90% duty cycle, continuous transmit mode.

In deep sleep mode, the ESP8266 maintains its RTC but shuts everything else off to hit about 60 µA. Respectable, if not MSP430 levels. It can pull upwards of 200mA while it’s transmitting, and I usually measure an average of about 75mA in normal operation. In deep-sleep mode I can get the ESP8266 Thing down to about 77µA.

There is a modification to be made – both in hardware and software – to get current consumption low. On the firmware end, the Espressif SDK has made a systemdeepsleep([uint32t timeinus]) function available, which puts the ESP8266 to sleep for a specified number of microseconds. When it wakes up, it begins running the user program from the very beginning. If you’re using the ESP8266 Arduino IDE, they’ve wrapped that function and another into a very nice ESP.deepSleep([microseconds], [mode])'' function. Here’s a quick example Arduino sketch for the ESP8266 that blinks the on-board LED 10 times, sleeps for 60 seconds, then repeats. <code> #include <Ticker.h> Ticker can periodically call a function Ticker blinker; Ticker object called blinker. int ledPin = 5; LED is attached to ESP8266 pin 5. uint8_t ledStatus = 0; Flag to keep track of LED on/off status int counter = 0; Count how many times we've blinked void setup() { pinMode(ledPin, OUTPUT); Set LED pin (5) as an output
blinker.attach(0.25, blink); Ticker on blink function, call every 250ms } void loop() { } void blink() { if (ledStatus) digitalWrite(ledPin, HIGH);
else
digitalWrite(ledPin, LOW);
ledStatus = (ledStatus + 1) % 2; Flip ledStatus
if (counter++ > 20) If we've blinked 20 times ESP.deepSleep(60000000, WAKERFDEFAULT); Sleep for 60 seconds
} </code> There are couple modifications to be made: one required, one suggested. To wake itself up, the ESP8266 uses the XPD pin to trigger its reset line on the rising edge , so those two pins need to be connected together. Wiring up XPD to DTR works. ( Note there is a small capacitor between them on Sparkfuns Thing board on the DTR line) ===== More data from expressif ===== can be found at
http://bbs.espressif.com/download/file.php?id=253&sid=398301f84155a628a3a39725226e7379 An extract from which deals with deep sleep
==== 6.systemdeepsleep ==== Function:
Configures chip for deep-sleep mode. When the device is in deep-sleep, it automatically wakes up periodically; the period is configurable. Upon waking up, the device boots up from userinit.
Prototype:
void systemdeepsleep(uint32 timeinus)
Parameters:
uint32 timeinus : during the time (us) device is in deep-sleep
Return:
null
Note:
Hardware has to support deep-sleep wake up (XPDDCDC connects to EXTRSTB with 0R).
systemdeepsleep(0): there is no wake up timer; in order to wakeup, connect a GPIO to pin RST, the chip will wake up by a falling-edge on pin RST
==== 7.systemdeepsleepsetoption ====
Function:
Call this API before systemdeepsleep to set what the chip will do when deep-sleep wake up.
Prototype:
bool systemdeepsleepsetoption(uint8 option)
Parameter:
uint8 option : deepsleepsetoption(0): Radio calibration after deep-sleep wake up depends on init data byte 108.
deepsleepsetoption(1): Radio calibration is done after deep-sleep wake up; this increases the current consumption.
deepsleepsetoption(2): No radio calibration after deep-sleep wake up; this reduces the current consumption.
deepsleepsetoption(4): Disable RF after deep-sleep wake up, just like modem sleep; this has the least current consumption; the device is not able to transmit or receive data after wake up.
Note:
Init data refers espinitdata_default.bin.
Return: true : succeed false : fail