Hey guys. New(ish) to arduino, and got an interesting request from a friend:
Would it be possible to build a system that would work effectively like RFID but over distances of up to 60 feet(18 meters) and also allowed the logging of anytime a signal was received? This would be communication between a unit mounted on a machine and another with an employee with the ehicle unit logging the data. I have some ideas, but I'd like to see what the forum has to say before I go forward.
I'll do my level best to answer any other questions you might have, but my knowledge is limited, so please be patient!
Such a system is known as a transponder and the thing like the tag in the RFID is going to have to be powered.
Okay. The "sending unit" (i.e. the one on the person) will have to be powered. I had a feeling that would be the case. With that(I know I'm asking for trouble here), how small a battery(physical size) could I run the sending unit from? My thought is to have the unit on the person basically in "listen mode" until it receives a signal from the vehicle unit, and only then start transmitting.
My thought is to have the unit on the person basically in "listen mode" until it receives a signal from the vehicle unit, and only then start transmitting.
Yes that is the way they normally work. In the RFID world they are known as "active tags".
how small a battery(physical size) could I run the sending unit from
Well from a very small coin cell. The problem is not that but how long can you run it for? That you will only know when you have got the system going and know the receive power consumption of the wireless system.
You can make it less by doing things like only listening at the start of every second.