/technologies/embedded/b/blog/posts/auto-wake-up-of-mfrc-522-rfid-moduleCan anyone help me on how to automatically wake MFRC 522 Mifare Reader up by the presence of a RFID Card. And after goes back to sleepen-USTelligent Community 12https://community.element14.com/technologies/embedded/b/blog/posts/auto-wake-up-of-mfrc-522-rfid-moduleTue, 01 Nov 2016 01:40:45 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:a6916834-a0be-4f77-b9d8-f26f866f9758dougw0<p>Many techniques have been proposed:</p><p><a class="jive-link-external-small" href="http://csserver.ucd.ie/~aruzzelli/pubs/SenseID07.pdf" rel="nofollow ugc noopener" target="_blank" title="http://csserver.ucd.ie/~aruzzelli/pubs/SenseID07.pdf">http://csserver.ucd.ie/~aruzzelli/pubs/SenseID07.pdf</a> </p><p><a class="jive-link-external-small" href="http://www.ti.com/lit/an/sloa184/sloa184.pdf" rel="nofollow ugc noopener" target="_blank" title="http://www.ti.com/lit/an/sloa184/sloa184.pdf">http://www.ti.com/lit/an/sloa184/sloa184.pdf</a> </p><p>You can also design your own... if you use a photoresistor to turn a fet on based on ambient light, it takes no power, but you will need some timing smarts to prevent false triggers at night.</p><img src="https://community.element14.com/aggbug?PostID=2163&AppID=7&AppType=Weblog&ContentType=0" width="1" height="1">