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By BuckyKatt
#30755 Hello.

New here and please bear with me, as I am still wrapping my mind around the current state of microprocessors available.

I have a project in mind which needs to be very low power, but when something triggers a PIR sensor, it needs to be able to take a 4 or 5MP photo and move it over WIFI relatively quickly. It would also be really nice if I could get the unit to Wake On WLAN, so I can control it remotely.

Its my understanding that the ESP8266 can be used as a microprocessor in its own right. Its also my understanding that the ESP8266 is not particularly speedy over WiFi.

What I would like to do is set the ESP8266 up in the lowest power state that would still have it listen for WiFi and watch a PIR sensor. If the PIR sensor is triggered, the ESP8266 will apply power to start a more powerful microprocessor (currently considering STM32L4, but open to suggestions). This second processor would snap a photo and send it out over WiFi, either using the ESP8266 or, more likely, a second, faster WiFi processor. It would then shut itself back off.

Would the ESP8266 be able to listen to a PIR and control the power of a second microprocessor? Could it also talk to the second processor? The ESP8266 boards I have seen so far seem to only have limited IO.

Also, assuming the ESP8266 is not able to achieve higher WiFi speeds and cannot talk with the second processor, I would have to use a second WiFi system. Since these units will be some distance apart, I will need to use external antennas... can two WiFi units share the same antenna?

So that's what I'm thinking. Please be gentle and feel free to correct my thinking or point me in a better direction. Thanks in advance.

BKNJ
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By eriksl
#31111 Have a look at the other ESP boards. Some have all of the 17 GPIO's exposed and you can use up to 14 of them (depening on what speed towards SPI FLASH you need etc.)

And yes you can communicate to other microprocessors, it's quite easy. I am doing it with ATmega328p's over UART, no problem. But it's really not necessary.