ESP8266 Community Forum

- Fri May 22, 2015 2:18 am #18141

Well I spoke too soon. As soon as I started messing with WiFi the board won't function unless Vcc=3.3V. I may switch back to the AT firmware and run more tests with it to check if this really is a Lua issue or ESP8266 sensitivity.

I've this ESP-01 testing being powered by a couple of AA batteries. Waking up every 15 minutes, reading a temperature sensor and the current supply voltage and posting the readings to the internet over Wifi. Its never been as high as 3.3v and has been going fine for some weeks now. Thats running on a sketch from the first 1.6.1 Arduino IDE release which i think uses the 0.9.5 SDK.

Here's the voltage graph:

AAs.png

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- Fri May 22, 2015 8:03 am #18168 Is this module running Lua or some other firmware? This is what is rather strange, because I have seen reports of people performing tests like this but I'm not getting the same results. Perhaps the ESP-12 modules I purchased have sub-standard flash and that is adding to the problems I'm facing?

- Fri May 22, 2015 8:16 am #18169

Is this module running Lua or some other firmware? This is what is rather strange, because I have seen reports of people performing tests like this but I'm not getting the same results. Perhaps the ESP-12 modules I purchased have sub-standard flash and that is adding to the problems I'm facing?

Programmed with the Arduino ESP8266 support - https://github.com/esp8266/Arduino - i'm not sure how that compares to Lua, but they use the same ESP SDK i think?

I've also tried some other batteries and ESP boards too - viewtopic.php?p=16829#p16829 - LIPO cells, coin cells, AA batteries, and ESP-01's, ESP-12's, and ESP-201's. They all seem to work below 3volts.

I noticed yesterday in the ESP SDK API Guide on page 119 it says "The range of operating voltage of ESP8266 is 1.8V~3.6V". I've gone quite a bit higher than 3.6v without trouble too.

- Fri May 22, 2015 9:37 am #18175 I'll have to give that a try today and see what results I get. I noticed that it doesn't appear to support the deep sleep function but in your comment you stated that you have the module sleep for 15 minutes, can you elaborate on how you did that or share your code?

I'm seeing current requirements of ~15mA at idle and ~70mA when I assume the WiFi is turned on so I'm sure that these can operate off of batteries. The problem I'm seeing is that it sometimes resets and some resets come back with the module pulling up to 400mA and you have to reset the module to bring it back.

To be honest, I haven't seen what I would call a true datasheet on the ESP8266, at least when compared to other microcontrollers I have used. When I find something close to a "real" datasheet I see that the operating voltage range is 3.0-3.6V but the I/O can operate at 1.8V. None of the ESP modules I have seen use an onboard voltage regulator to generate 1.8V so all of the modules operate with 3.3V I/O. This is very common for processors to operate at 2 different voltage levels, 1 for the main and another for the I/O.

Take a look at this document on how they specify Vcc.
http://esp8266.ru/download/esp8266-doc/april-2015/0B-ESP8266__Hardware_User_Guide__EN_v0.7.pdf

I definitely wouldn't operate the module at more than 3.6V for long periods of time, that could be asking for trouble