ESP8266 Community Forum

- Thu Jul 14, 2016 5:02 am #50739 Hi y'all!

Imagine an ESP8622 in a battery-powered portable device. I'm wondering what are my options to get the ESP8622 wake up from a sleep mode, when a specific WiFi SSID is (suddenly) present in the environment. This presence should be the signal for the ESP8622 to start doing things — otherwise it should be asleep.

In other words: Can you think of good ways, to have the ESP8622 in a super low power mode, but like checking for SSID presence as well?

Or: Is there another way, for instance with an additional external component, that listens low-powerly to a specific WiFi beacon, to then trigger the RST on the ESP8622 to wake it up?


Any suggestions and ideas are glady welcome!

„ 2 … 1 … Risiko ! “

- Sun Jul 17, 2016 4:45 pm #50921 Hi,

Imagine an ESP8622 in a battery-powered portable device. I'm wondering what are my options to get the ESP8622 wake up from a sleep mode, when a specific WiFi SSID is (suddenly) present in the environment. This presence should be the signal for the ESP8622 to start doing things — otherwise it should be asleep.

No.
If you give us an idea of what you are wanting to achieve I'm sure someone can help.

- Sun Jul 17, 2016 5:29 pm #50928

I'm wondering what are my options to get the ESP8622 wake up from a sleep mode, when a specific WiFi SSID is (suddenly) present in the environment. This presence should be the signal for the ESP8622 to start doing things — otherwise it should be asleep.

In other words: Can you think of good ways, to have the ESP8622 in a super low power mode, but like checking for SSID presence as well?

It has to be "awake" to look around and get the available APs, so no, there's no way to "wake" upon detection of a given SSID. Best idea is to simply wake from deep sleep every X minutes, look for the desired SSID, and go back to sleep if it isn't present. Averaged out, that's still pretty low power.

- Mon Jul 18, 2016 1:08 am #50944 The idea is, that I plan to have some sensor units outdoors on several places. These units have the ESP8622. I now want to “collect” the data by occasionally walking around with a laptop’s WiFi and when I'm near such a sensor unit, I want it to wake up (from a battery-saving sleep state), start to connect and transmit its data.

The crucial thing is the “listening for a specific WiFi to connect” during a battery-saving low-current state. I’m aming for µAmps, if it’s possible. In other words: I’m wondering how I could maximize battery life, while also “looking for WiFis”.

Or to put it this way: To save battery life, the ESP8266 is not meant to transmit constantly — but automatically should I be around with my laptop’s WiFi.

So letting the ESP8622 look out for a WiFi every x minutes, when in reality I maybe there once a week, sounds not very efficient.

—

I wonder: since RFID technology is common nowadays, shouldn’t it be possible to let a 2.4 GHz signal induce a small current, wich then powers circuitry to trigger the RST on the ESP8622? Something like that …

„ 2 … 1 … Risiko ! “