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By nonokunono
#8994 hi,
a few companies, namely Aeroscout, Ekahau and Zebra offers very expensive WiFi tags that can be affixed on logistics goods (shopping carts, packages) that can then be tracked by existing WiFi infrastructure. The tracking typically happens by infering the location of the tag using the received signal strength (RSSI) and RF signature.
Major concerns of these types of systems are
1) very hard to get a sample wifi tag through them or their channel partners,
2) have to work with yet another 3rd party location engine
3) typically not a fixed pricing (charges you a lot more if you are an "enterprise" entity)
4) lets face it, those enterprise WiFi tags under the hood sucks !

It would seem to me ESP8266 can be the cheaper, more robust alternative for construction of these WiFi tags.
The esp8266 would not have to do much beyond wake up every 1 minute, then issue a probe request. A seperate
uC can be used to toggle the sleep wakeup cycle (for example, completely turn off esp8266 using a FET) to further reduce sleep current to under a few uA as typicaly these WiFI tags advertise over 4 years of continuous runtime (albeit , not emiting probe request as frequently as 1 minute)


is this something people would be interested in pursuing ? has anyone done something like this ?
thanks
User avatar
By alonewolfx2
#9042 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 :)
User avatar
By ArnieO
#9045 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.
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By GeoNomad
#9091
nonokunono wrote: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