ESP8266 Community Forum

- Sat Dec 13, 2014 12:29 am #4725 Hi guys,
I've tried to analyze my ESP module using oscilloscope, measure current by resistor 0.2mOhm 1%, 3v3, this is results:
+ On TCP/IP connected: 15.19mV ~ 75.95mA

20141211_720937.png

+ On downloading: 23.27mV ~ 116.35mA

downloading.png

+ On boot, wifi not connected: 15.64mV ~ 78.2mA

onboot.png

+ On deep sleep: 0.014mV ~ 0.7 (incorrect, its too small)

deepsleep.png

+ After deep sleep without wiring GPIO16 and RST <<< this is my problem

afterdeepsleep.png

My problem is:
+ I don't understand after deep sleep, GPIO16 don't reset, weakup and ESP chip doesn't do any thing, but leak about 14mA?
+ i want to collect data from a sensor every 5 second, and transmit to server every 1 hour, so i need to disable wifi to reduce current, but esp used a lot current when it haven't connected to wifi, any ideal?
+ i want to collect data from a sensor every 5 second, and transmit to server every 1 hour, so i need to disable wifi to reduce current, but esp used a lot current when it haven't connected to wifi, any ideal?
+ deep sleep api only work with time not more than 2147483648 milisecond, about 35minute, how can i sleep longer?

Thanks

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- Sat Dec 13, 2014 2:57 am #4730 You can use wdt reset after every collect data and reset tmr for new 35 minutes. That's the only way for now. And you must connect gpio16 to reset for wake after deep sleep. 0.017 MA not bad. I saw just 0.045ma with esp03(winbond flash)

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- Sun Dec 14, 2014 6:05 am #4783 I made a short script for measuring DS18S20 temperature, sending it to TCP port 8888 of my laptop and entering deep sleep for 30 seconds.
Everything is fine, except...
I pluged the device to 3.4V power source throuch 2.5ohm resistor (4x10ohm in parallel, smallest I had at home).
I am measuring voltage on such resistors.
I have just a crappy multimeter (costed $17 2 years ago).
The smallest range I can measure is 200mV.
When running the device, the voltage is from 80mV to 170mV - which translates to 32 to 70mA.
However, when entering the deep sleep, the voltage is funny - sometimes it is just 0.1mV - translating to 40uA - just great.
But, sometimes, the voltage during deep sleep stays at 1.6mV - that means 640uA - 16 times the original value.
And sometimes, with no apparent reason, the voltage stays as 2.6mV - 1.04mA.

Of course, my code includes setting the 1-wire line to high impedance input, instead of output, to avoid powering the DS sensor during sleep.

It runs a cycle as described, last 5 measurements are:
1.7mV
1.7mV
3.7mV
0.1mV
2.1mV
I cannot explain the results.

Can anyone else share their experience?
This post has originaly been posted here.

- Fri Jan 09, 2015 9:48 pm #6868 I assume you measured the current while the board was powered by 3.3V?
Can you repeat the measurements with a lower voltage, like 2.0V?
According to specs, the module works between 1.7V - 3.6V, however below 1.9V my uart-usb converter stops working.

According to my lab power supply (not very accurate), the current consumption stays at 70mA, regardless of the voltage. This means if someone is using a switching power supply and wants to save power, they should lower the operating voltage.

• 3.3V * 70mA = 0.23W
• 2.0V * 70mA = 0.14W

What do we know about the onboard voltage regulator?
Also interesting to know would be if the output RF power depends on the operating voltage.

Last edited by Fr4gg0r on Sat Jan 10, 2015 11:29 am, edited 1 time in total.