I have a nodemcu connected to a PN532, reading tags and notifying Home Assistant only when a recognized tag is read.
Now, it isn’t easy to have AC power in the place where I need to install this device, but I think I can get a decent life on a 9V battery, since I will have to read tags and connect to the wifi to notify Home Assistant just a couple of times a day.
Of course the ESP should be in deep sleep all the time, until a tag is read. How can I achieve this? I believe I have to connect D0 to the RST pin, but can I give the wake up signal from the PN532, such that it is only woke up when a tag is read?
Alternatively I would have to add a switch and manually wake the ESP up before getting the tag on the reader…
Thanks for your suggestions