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Project Help and Ideas » Nerf Gun Sentry

October 10, 2012
by Drwish
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So I am working on a project for my Intro to Engineering class. My partners and I are making a Nerf Sentry gun that will fire when motion is detected. At it's simplest, it must not fire on anyone with an RFID. For more pizzazz, it should be able to distinguish between friendly RFID and non-friendly RFID (fire anyway).

I need someone to point me in the right direction.

I know that my gun has to have an RFID reader and that it should be able to read RFID tags at a max of 10 feet. What products would you recommend I use? Looking at Digi-key, I arbitrarily chose this Transciever. But I have no idea how I would integrate this with the nerdkit. What do you guys think?

Also, what motion detector would you guys recommend I use? If we can successfully implement all of the above, I was thinking about mounting the gun on a swiveling base that can be controlled by a servo. That way, we could make our gun point in the direction of the detected motion somehow.

Basically what I'm asking is how do I get started on this thing?

October 10, 2012
by Ralphxyz
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Now this sounds like a great project.

The IC you are looking for is for short range applications.

I believe 10' is long range.

The specsheet does give you a nice application schematic so you could build an operating circuit from it but I worry about the range.

It seems as if the range should depend on your radio.

Of course if you have to build your own radio there are all sorts of FCC regulations to worry about.

But it should be fun.

Interfacing this chip with the Nerdkits mcu would be "fairly" easy. It uses I2C as it's serial communication protocol and there are some great I2C articles here in the Nerdkits forum.

There are lots of RFID forums and newsletters available.

Ralph

October 10, 2012
by Drwish
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So it seems that passive RFID tags are out of the question because getting/making an RFID reader that is capable of reading at 10 feet is incredibly expensive.

That leaves active RFID tags. The cheapest premade active RFID tag that I could find is around $20. Our project cannot exceed $100. That means we have to figure out how to make our own active tags.

As I understand it, an active RFID tag has 3 basic components:

A power source. A transmitter IC And an antenna.

The power source and antenna are easy to figure out, but what about the transmitter? Are there any cheap <$10 transmitters that I can use?

October 10, 2012
by Drwish
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Also, do you have any RFID forums that you would recommend?

November 14, 2012
by technogeek3000
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no

November 15, 2012
by Ralphxyz
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Sorry never did answer this, jus google RFID and you will find forums and lots of great rfid sites there are magazines with reader forums.

December 04, 2012
by Drwish
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For anyone who cares, I ended up going the Arduino route, with passive, short range UART RFID scanner.

Here is the YouTube for the finished project!

December 05, 2012
by Ralphxyz
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Good job Drwish !!

Ralph

December 05, 2012
by pcbolt
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Nicely done. It's too bad you couldn't get a cheap long range RFID scanner like you wanted, but you certainly passed the "proof of concept" stage and made it work. It might be possible to setup a series of IR beams and sensors and create a secret pattern of breaking the beams in a certain order to keep you safe from the Nerf Gun.

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