ESP8266 Community Forum

- Tue Sep 15, 2015 10:23 am #29083

... working extended time on battery ...

needs more detail on what "work" has to be done during this time.
"running extended time on a CR2032" means to me it is either running on 32kHz clock crystal and therefor can't do anything really meaningfull at all or is sleeping most of the time.
As for sleeping, ESP in light sleep (no WiFi) has ~0.5mA, deep sleep has ~10µA consumption and sub µA in power down mode (ref: http://bbs.espressif.com/viewtopic.php?t=133).
The last two won't be beaten by much on other LP µCs, but overall performance (incl. WiFi) is unmatched up to now.
Granted, to gain most from the low power modes it needs a little brain grease compared to other (unfortunately general) low power solutions.

Yes, I probably should have been more specific.

Mostly, I am thinking about remote sensing (PIRr, thermometers, ...). Well, that probably can done within a "power-on + do task + go to sleep" cycle, but just sending data through WiFi seems too power-hungry, if I am not mistaken. Sometimes I would like to send commands to the sensors, too, and that is not possible if the sensor is sleeping; perhaps I should design around this issue.

I will have a look at that table, and investigate how to work with the different modes, maybe I do not need a different platform after all. Many thaks!

- Wed Sep 16, 2015 9:16 am #29165 One big difference is that ESP8266 is WiFi ! Probably all the "low-power alternatives" are either 2.4 or sub-GHz modems that do _not_ connect to a WiFi access point. So you move the problem.

I used for years panstamp modules, very happy with them, and the "battery" module will work for several month on one single AA cell ! It's all open source, and there are as well sample sketches to create a WSN (Wireless Sensor Network). Pretty powerful.

Then you can either used a Raspberry Pi as gateway from that Wireless system to the Internet. The SW for that also exists, called Lagarto, but I never used that part.

A few other that are similar are Dash7 and OpenKontrol. I talked with the founders, but never used those.

- Wed Sep 16, 2015 10:12 am #29174 Yes, my initial idea was to use a non-wifi network for the low-power sensors, and a gateway to the wifi network on a high-power device. I am investigating the low-power state of the ESP devices, and right now I am re-engineering the project to use only ESP devices.

- Wed Sep 16, 2015 1:42 pm #29189 Like schufti said already, the ESP can be pretty low powered - use sleep and switch the raido off when its not needed. I've this one running off a couple of AA batteries waking up once an hour with the radio off and just once a day using WiFi to publish data, its been going for months and the battery voltage is still well over 3.2 volts so it will probably last a year or two.