ESP8266 Community Forum

- Fri Feb 06, 2015 9:57 pm #9152

I think battery consumption/capacity is the key challenge or such a device. If it wakes up for 15-30 seconds one time per hour, that is order of magnitude 0.5 - 1 mAh consumption each hour. The capacity of a button size battery is order of magnitude 250 mAh, giving 2-4 weeks battery time.

We maybe interested in using either 6000mAh+ LiPo battery (device need not be too small) or AA batteries

- Fri Feb 06, 2015 9:58 pm #9153

that can then be tracked by existing WiFi infrastructure.

I am assuming the infrastructure is within your organization, so you already know the locations.

If it is external, then there are legal questions to be asked about connecting to a WiFi access point, even though it may not be secured. This varies from jurisdiction to jurisdiction.

For test code, I offer an example of an ESP8266 implementation that connects to the strongest open hot spot visible.

http://benlo.com/esp8266/esp8266Project ... spotfinder

hi, yes, typically the WiFi infrastructure is in house.

- Fri Feb 06, 2015 10:00 pm #9154

maybe sleep current very slow but its consuming almost 80ma on wake state. if module wake every minute, 4 year battery life just a dream

Yes you are correct, the battery consumption is major challenge for such device. I wonder if these companies have used more efficient WiFi chipsets that are manufactured only for sending probe requests and nothing else. Having been in the enterprise enviroment and saw the amount of garbageware (soft and hard) they tried to sell I highly doubt it. I am pretty sure the advertised 4 year runtime is only when the WiFi tag is transmitting at a very low frequency (e.g once per 3 hours or less )

- Mon Feb 09, 2015 4:29 am #9304

We maybe interested in using either 6000mAh+ LiPo battery (device need not be too small) or AA batteries

There are restrictions on Lithium batteries on airplanes, but as long as you do not exceed 100 Wh capacity, you should be ok: http://www.iata.org/whatwedo/cargo/dgr/Documents/LithiumBattery_PassengerFlyer.jpg
(Your indicated 6000 mAh * 5V = 30 Wh)