One of our challenges is that when we opened we used some Wiegand RFID readers for our door entry system and fed the UIDs they gave into our membership database. Later on we found out that these UIDs weren't the same as the UIDs other things reported. I did some fiddling around and realised a simple XOR and byte reshuffle that fixed this so we were back in business until I built something using this and found it wasn't right for some issued cards.
Then the access control project got shelved.
Having dug out my access control mockup again I armed myself with a pile of cards that I know don't map IDs how I thought and quickly realised if they have a 7-byte UID then the byte order reshuffle is different than for a 4-byte UID. So we're potentially back in business.
For the hardware I've taken a bit of an executive decision on the basis that whoever does the work gets to say how it's done, otherwise endless bikeshedding occurs. The hardware will be based on an Olimex ESP32-EVB which is an ESP32 dev board with Ethernet, onboard relays and a bunch of hardware we probably don't need. They're reliably available and properly certified.
It also breaks out some GPIO and has LEDs and somewhere to connect a sounder. I'm not even sure if we'll use a sounder, but I just wanted to get the board ordered.
Work on the software has been ongoing for ages but I've started poking at it again and one of the other Trustees already did a bunch of stuff in our membership database so I'm hoping this project can get done without too much pain.
Each tool will have different ways of limiting its use but my expectation most will already have an interlock or emergency stop that can be connected to one of the onboard relays of the EVB. I'd not expect these devices to control the main power feed to the tool unless it's a very small one.
