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11 years, 6 months ago.
RFID wall project -- What do I need?
I'm a software engineer and I don't know very much about RFID other than it's prox-based and returns a 10-digit UID. Basically I want to have an entire room with a bunch of sensors on the walls. As the tags come within range (0.5m would be the most that's needed; too far of range would actually be bad), I want to send my server a message with the scanner and tag IDs. It'd be nice if I could keep the price of every sensor to < $15.
I found a tutorial on how to get the reader info in python, and once I'm in software, I can obviously take it from there easily. Some of the things I'm not sure about:
- Do I need a scanner for every sensor or would I just use separate antennae with a single scanner?
- Will putting them behind objects interfere with or even block the reading? Ideally, I want to be able to put them behind plywood, concrete, and urethane, but I can put them on the outside if required.
- Any advice on which specific one I should buy?
2 Answers
11 years, 6 months ago.
Well wess, they are two type of rfid tags: passive and active
The passive tag doesnt have much range (10cm-few meters) They are inexpensive too, You will need to approach the tag to the reader
The active that have a long range (10mts - 500 mts) but they are expensive and you need a special reader
In theory if you use a passive tag you will need one reader in every place you want to control (ex: a wall, a door, a window).
if you use an active tag you will need only one reader because the active tag have its own autonomous energy source to propagate the signal to the reader
I hope this information help you
Greetings
Thanks Ney.
I am pretty sure I want to go with passive tags. The idea is to have people interact with the wall via cheap bracelets, and the number of visitors could easily hit the thousands. There are a fixed number of readers, though I would like it to be in the hundreds if that's still cost effective. They also will not be very close together, maybe 50cm at the closest, but usually more like 200cm.
Short range is also okay. I am looking to have people activate a sensor when fairly close. Any reader with a 25cm-50cm range would be fine.
So it sounds like I will in fact need a reader for every point on the wall then?
I thought the way it worked was that an antenna would send a signal to the tag, which uses the signal to power itself and send back the UID, then the antenna signal is sent to a reader that can interpret the signal. In that case, I would think there would be a reader that has multiple antenna ports.
Any specific recommendations on what I need to get started?
posted by 07 Jun 2013I am fairly certain their aren't readers with multiple antenna ports. Well maybe there are, but I expect them to be quite expensive. You could multiplex several antenna's to a single reader, but that will be far from trivial.
Considering you are more into the software than hardware side, I think you have to go for a reader for every sensor.
posted by 08 Jun 2013That makes sense. The other issue is which reader to get. Basically I'm looking to have an omni-directional range of 1-2 ft, with as low cost as possible. It seems like everything I've found is either expensive and has a ridiculous 15+ ft range, or is cheap and has a directional 3" range. Any recommendations for something that will fit my specs?
posted by 08 Jun 2013
11 years, 6 months ago.
(nt)