Long-range Bluetooth Wardriving Rig

April 15, 2011 by Mike Nathan 56 Comments

bluetooth_wardriving

[Kyle] was digging through a box of junk he had lying around when he came across an old USB Bluetooth dongle. He stopped using it ages ago because he was unsatisfied with the limited range of Bluetooth communications.

He was going to toss it back into the box when an idea struck him – he had always been a fan of WiFi wardriving, why not try doing the same thing with Bluetooth? Obviously the range issue comes into play yet again, so he started searching around for ways to boost his Bluetooth receiver’s range.

He dismantled the dongle and found that the internal antenna was a simple metal strip. He didn’t think there would be any harm in trying to extend the antenna, so he soldered an alligator clip to the wire and connected the CB antenna in his truck. His laptop sprung to life instantly, picking up his phone located about 100 feet away in his house. He took the show on the road and was able to pick up 27 different phones set in discoverable mode while sitting in the parking lot of a fast food chain.

While it does work, we’re pretty sure that the CB antenna isn’t the most ideal extension of the Bluetooth radio. We would love to see what kind of range he would get with a properly tuned antenna.

Keep reading to see a quick demonstration of his improvised long-range Bluetooth antenna.

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Stepper Directed HDTV Antenna

January 26, 2011 by James Munns 22 Comments

Credit: http://www.instructables.com/id/Computer-controlled-OTA-TV-antenna/

Broadcast TV has come a long way from adjusting the rabbit ears on top of the set just to get a fuzzy black and white picture. While nowadays there are often HD signals broadcast in most areas, it can often still be critical to redirect an antenna to get the best possible signal. By harvesting a stepper motor from an old 5 1/2″ floppy drive, and using a PC’s parallel port to control it, this adjustment can be handled automatically. Broadcast tower locations are easily found online, and once you have calibrated your stepper to face North, you are on your way to free HDTV reception.

What we would like to see is this antenna attached to a HTPC, and some kind of script to automatically direct the antenna for the best possible signal for the current channel. If anyone out there makes this happen, be sure to let us know.

Nokia Internet Key External Antenna

January 17, 2011 by Mike Szczys 13 Comments

[Maurizio] was having some reception issues with his wireless internet and set out to add an external antenna to the USB dongle (translated). He had previously poked around inside of the Nokia internet key to find that the internal antenna was a flexible circuit substrate wrapped around a plastic box that made contact with main circuit board via a spring connector. This plastic frame is just right for mounting an SMA connector in just the right place for it to stick out the end of the case as seen in the picture above. It gives him better range, but since speed depends on how much traffic the wireless node is under, it’s not a guarantee that you’ll get a snappier connection after this hack.

Plantenna: The Plant Antenna

October 20, 2010 by Jakob Griffith 37 Comments

The back story behind [Mike] experimenting with plants as AM radio transmission antennas antennae is rather interesting and worth the short read. But for those who just want the facts, [Mike] took an ATMega324, modified the PWM output into a sinusoidal AM signal (using a simple form of RLC circuitry), and connected the circuit to a plant no plants were harmed in the making of this project. The results? Well we’re not ones who would spoil the surprise, you’ll have to see for yourself in the video after the jump.

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WiFi AP Gets Antenna Augmentation

September 23, 2010 by Mike Szczys 29 Comments

Feeling bad that his access point was being made fun of by models with beefier external antennas, [Customer Service] decided to do something about it. After cracking open the Asus wl-330ge he found it would be quite easy to add a connector. This access point has two internal antennas that are quite small and use a spring connection to the signal and ground pads on the PCB. Those pads are fairly large and separated, making it easy to solder the connections. Scavenging an antenna connector from an older device, [Customer Service] soldered it in place and drilled a mounting hole in the plastic case. After flashing DD-WRT firmware he’s now got everything he wants from the little guy.

Building A Yagi-Uda Antenna

August 13, 2010 by Mike Szczys 35 Comments

[Tommy Gober] built this Yagi-Uda antenna that has some handy design features. The boom is a piece of conduit with holes drilled in the appropriate places. The elements are aluminum arrow shafts; a good choice because they’re straight, relatively inexpensive, and they have #8-32 screw threads in one end. He used some threaded rod to connect both sides of the reflector and director elements. The driven elements are mounted offset so that a different machine screw for each can be connected to the appropriate conductor of the coaxial cable. The standing wave ratio comes in right where it should meaning he’ll have no trouble picking up those passing satellites as well as the International Space Station.

PCB Trace Antenna

August 5, 2010 by Jakob Griffith 19 Comments

If you’re working on a device that includes RF wireless, [Colin’s] Guide to PCB Trace Antenna Design might clear some headaches when sending off for PCBs. While it is directed at devices transmitting at 2.4GHz, the techniques and recommended equipment (read: espresso smith charts and network analyzers) should work for almost any frequency. While trace antennas aren’t as easy to implement as a measured wire, the space benefits make up for the difficulty. Unless you don’t mind how larger your project is, did someone say cantenna?