to piggy back on this i designed the Michtastic node. its a low cost of entry node that should be very cost efficient to build yourself.
i got 30 made for around 150$ plus the cost of the pro-micro.
In addition to that the RFID Door Simulator project has been getting pretty popular.
This one is about 30$ in parts plus the cost of the HID Reader (R10/R15).
I have videos of this functioning in my thread here
Also you can look at any of @Chimpofm projects, his always give me a ton of inspiration.
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