RFID proximity device

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   Hi guys,
We have an RFID-based project in our college class and your help will be greatly appreciated to say the least. We know little about RFID technology, but we are truly interested in learning more about it.

We want to build a device that is composed of an RFID reader and an active RFID tag. We want the RFID reader to detect whether the active RFID reader is within range. 

So basically it will be used for 2 people that wants to stay together (parent and child), and when one goes further than a designated distance, the RFID reader will start to beep.

We want to know the smallest possible component we can get for this and some tips for building and programming it. 

Where can we buy the components?

Thanks in advance

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need4innovation Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 09 October 2011 Location: Wisconsin Status: Offline Points: 2	Post Options Post Reply Quote need4innovation Report Post Thanks(0) Quote Reply Topic: RFID proximity device Posted: 09 October 2011 at 6:28pm
	Hi guys, We have an RFID-based project in our college class and your help will be greatly appreciated to say the least. We know little about RFID technology, but we are truly interested in learning more about it. We want to build a device that is composed of an RFID reader and an active RFID tag. We want the RFID reader to detect whether the active RFID reader is within range. So basically it will be used for 2 people that wants to stay together (parent and child), and when one goes further than a designated distance, the RFID reader will start to beep. We want to know the smallest possible component we can get for this and some tips for building and programming it. Where can we buy the components? Thanks in advance

amal Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Admin Group Joined: 22 November 2005 Location: United States Status: Offline Points: 2060	Post Options Post Reply Quote amal Report Post Thanks(0) Quote Reply Posted: 10 October 2011 at 10:45am
	Basically what you guys are looking for is a simple transmitter/receiver pair where the receiver will emit an alarm of some kind should it lose signal from the transmitter. This could be done with simple analog circuits (i.e. without RFID at all), however it may actually be easier to go ahead and build this using pre-made digital components. Of course, this has already been done commercially. This is one of the smallest devices I know of that already does this; http://blog.amal.net/?p=425 So, getting back to your project. Unless your team has electronics experience and microchip programming experience, you are not going to find a list of components you can snap together like legos to make this work. What kind of smarts do you have on your team?
	Amal ;) www.amal.net

need4innovation Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 09 October 2011 Location: Wisconsin Status: Offline Points: 2	Post Options Post Reply Quote need4innovation Report Post Thanks(0) Quote Reply Posted: 13 October 2011 at 12:54am
	Hi Amal, First of all, thank you so much for the quick response! We realized that RFID technology is too much for a simple device that we were trying to make. After more planning, we have finalized the exact type of product we want to produce. Instead of just having 2 components where 1 will start making a sound if the other is out of range, we want to have 1 receiver and 8(or more) transmitters. We want the receiver to start making a sound even if one of the transmitters are out of range (preferably around 15 meters) Both the transmitter and receiver should be powered by batteries. I'm thinking that this would require RFID technology? We have some circuitry and programming knowledge. However, we lack the knowledge of RFID and its components. If its not too much, can you give us some suggestions on how we can go about building this product? (such as the possible components we need) Thank you for your time

amal Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Admin Group Joined: 22 November 2005 Location: United States Status: Offline Points: 2060	Post Options Post Reply Quote amal Report Post Thanks(0) Quote Reply Posted: 13 October 2011 at 10:53am
	Basically, because you need to uniquely identify each transmitter, this is technically RFID. The first RFID system was used by the British during WWII to detect friendly aircraft. A radar signal was bounced off a special reflector in the nose of British aircraft. No reflector, and the plane did not have that special bounced signal and was considered hostile. Anyway, all you need to do is look at something like Ananiah or OpenBeacon. I would suggest starting with something like Ananiah because of the simple construction. Basically it is a small PIC processor that is programmed to output a unique 4 character string on a regular basis (every second I think), and a transmitter module that takes the output from the PIC and transmits it. The receiver simply consists of a receiver module that receives the data and outputs it via RS232. You just need to connect the receiver module to a PIC or similar microprocessor, and program it to watch for specific IDs being transmitted over the air. When a particular ID has not been heard from in a while, an alarm could sound. Of course, there are all kinds of particulars like having a way to keep time (may require a RTC module), enable and disable certain tags so not all 8 tags have to be on and part of the system at all times (maybe only 4 tags will be required to keep tabs on 4 children), and possibly a way to differentiate the alarm sounds for each tag.
	Amal ;) www.amal.net