# My Bluetooth Range Extender

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I use Bluetooth with Lego Mindstorms NXT most of the time, but when I need to connect to it when it is in the living room 20 feet away and around corners/through walls, it doesn't work! So, I used this I'ble: https://www.instructables.com/id/Increase-and-extend-the-range-of-a-USB-Bluetooth-d/ to add an external antenna to my Bluetooth dongle, and made a reflector out of a tin can (with a Dremel!). I'm not sure how much this helps, but it definitely does.

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## 9 Discussions

It's a really AWESOME idea, I've extended my range of WiMax modem, Thanx man

Good work.

I have a suggest: the focus of a spherical concave mirror (in this case cylindrical) is located halfway between the reflecting surface and the center of curvature. If the issuer is in focus, the reflected beam is parallel in theory, that is with zero dispersion. But being in the center of curvature, the dispersion is too large, 180 degrees. I would try an intermediate option, pulling up the transmitter nearer to the can.

I can't see by the photos if your emitter is in the curvature center or not.

3 replies

I'm not sure what you mean by the curvature center, but it's pretty much on the edge of the can. I'll try your suggestion and let you know how it turns out.

The curvature center is the axis of the can. If the emitter is in it, the reflections disperse 180º (can you imagine it?). If it is halfway near the rear, the reflections is theoretically near 0º, too little. You can experiment, the optimum must be between both positions.

Anyway, 180º is better than 360º without the can...

In that case, it is in the curvature center. Yeah, I just want to keep the radio waves from going out the window so more end up in the living room.

Good combination for bluetooth, since the dongle's antenna is almost always pitiful.

I did this 'ible a while ago, the comments have a lot about maximizing range, specifically, half way through the can isn't as good as a quarter way in, so it's fully inside the dish.

Though I went with half because I needed greater range but not so badly that I cut down the "viewing angle" by the full 180 degrees.