Weightless, The Hopefully-not-vaporware Internet Of Things Chip

February 14, 2013 by Brian Benchoff 77 Comments

Weightless

Imagine a single chip able to interface with your Ethernet, USB, and serial devices, turn those connections into wireless radio signals with miles of range, able operate off a single AA battery, and costs less than $2. That’s the promise of the Weightless special interest group that wants to put several hopefully not vaporware radio chips in the hands of everyone on the planet.

Long-range wireless networks are a tricky thing; for home networks, Bluetooth and WiFi reign supreme. Venturing into the outdoors, or really any place more than a few hundred feet from a WiFi repeater is a challenge, though. If you’re trying to send data to a fleet of automobiles, track an endangered animal, or make a smart power grid, your only real option is a cell phone tower with very high costs in hardware and battery life.

Weightless hopes to change that with a small radio chip that includes a MAC, PHY, and all the components necessary to turn just about any digital connection into a wireless link between devices. The radio will operate in the spectrum left behind by UHF TV (470 – 790MHz), and the folks working on already have some reference designs etched into silicon.Don’t expect this to replace WiFi, cellular, or Bluetooth, though: according to the getting to know Weighless book, the designers are aiming for a data rate of only a few kB/s.

Still, it’s a great use of now unused spectrum, and would fill a huge gap in what is readily possible with homebrew Internet of Things things.

Tip ‘o the hat to [Mark] for sending this one in.

Arduino As An Inexpensive Ham Radio Frequency Counter

February 9, 2013 by Mike Szczys 8 Comments

[Todd Harrison] really has our number. Like him, we don’t want to spend money when we don’t have to, and hacking our own solutions is a lot more fun anyway. This time around he’s helping out a friend who is a ham radio enthusiast. The friend’s radio didn’t come with a frequency display, and buying the add-on would cost more than the radio did. So [Todd] has set out to build an Arduino frequency counter for a Kenwood TS-520S HF ham radio.

This post (and the video found after the break) doesn’t cover the entire project. It’s rather involved just to make sure that [Todd’s] initial idea is viable so he spends about 35 minutes explaining the problem, then measuring the radio outputs and testing to see that the Arduino can read them accurately. Because the radio has a very large range of operation, [Todd] will need to add external component to facilitate this. That extra circuit design will be the topic of the next project segment.

Continue reading “Arduino As An Inexpensive Ham Radio Frequency Counter” →

BladeRF, Your Next Software Defined Radio

February 2, 2013 by Brian Benchoff 74 Comments

By now you might have a bit weary of your small and inexpensive TV tuner dongle software defined radio. Yes, using a USB TV dongle is a great introduction to SDR, but it has limited bandwidth, limited frequency range, and can’t transmit. Enter the bladeRF, the SDR that makes up for all the shortcomings of a USB dongle, and also serves as a great wireless development platform.

The bladeRF is able to receive and transmit on any frequency between 300 MHz and 3.8 GHz. This, along with a powerful FPGA, ARM CPU, and very good ADCs and DACs makes it possible to build your own software defined WiFi adapter, Bluetooth module, ZigBee radio, GPS receiver, or GSM and 4G LTE modem.

It’s an impressive bit of kit, but it doesn’t exactly come cheap; the bladeRF is available on the Kickstarter for $400. The folks behind the bladeRF seem to be doing things right, though, and are using their Kickstarter windfall for all the right things like a USB vendor ID.

There’s a video of two bladeRFs being used as a full duplex modem. You can check that out after the break.

Continue reading “BladeRF, Your Next Software Defined Radio” →

Great Antenna For Software Defined Radio Is Really Easy To Make

January 28, 2013 by Brian Benchoff 47 Comments

The University of Kent’s hackerspace, TinkerSoc, recently had a talk on software-defined radio using an incredibly inexpensive USB TV tuner. Of course this is nothing new to Hackaday readers, but they did manage to build one of the best antennas for their TV dongle. It’s a discone antenna, and is perfectly suited for tuning into a whole bunch of really cool things such as weather balloons and aircraft transponders.

The idea discone antenna looks exactly like its namesake; a metal disk attached to a metal cone. Of course with the frequencies the RTL software-defined radio deals with, it’s rarely necessary to build antennas out of sheet metal. The team at TinkerSoc built their discone out of galvanized garden wire and attached it to the input of their TV tuner.

All the dimensions for their discone antenna were gleaned from [ve3sqb]’s antenna design programs. Since TinkerSoc designed their antenna for 110 MHz, it ended up being pretty large. For higher frequencies, though, a discone antenna become fairly small and more than portable enough for a mobile rig.

Adding Shoulder Buttons To An RC Transmitter

January 26, 2013 by Brian Benchoff 6 Comments

radio

[Gerard] does puppeteering and animatronics work, and to remotely control his creations and characters he uses an off-the-shelf remote control radio. It’s you basic 6-channel setup, but [Gerard] wanted a way to control eye blinks and other simple actions with the press of a button. Sure, he could use the toggle switches on his transmitter, but he wanted something that wouldn’t require turning a servo on and off again. To fix this problem, [Gerard] added shoulder buttons to his transmitter with only a little bit of soldering.

[Gerard]’s transmitter uses toggle switches to send a signal on channels five and six. To add his push buttons, he simply drilled a hole in the plastic enclosure, installed a pair of push buttons, and wired them in parallel to the toggle switches.

Now [Gerard] has momentary switches on channels five and six, perfect for making his creations blink. Since the buttons are wired in parallel with the switches, flicking the switches to the ‘on’ position in effect takes the button out of the circuit, just in case the transmitter gets jostled around.

Raspberry Pi Used As A Beacon Transmitter

January 25, 2013 by Mike Szczys 14 Comments

[m0xpd] got his hands on an inexpensive AD9850 DDS Module from eBay but needed a way to control it. He took inspiration from the projects that used a PIC microcontroller, but decided to add his own twist by using a Raspberry Pi to build a multi-mode beacon transmitter.

At the center of this breadboarded circuit lies the green AD9850 module. To its left is a level converter he built to get the 3.3V levels from the RPi board to work with the rest of the 5V hardware. The signal then feeds into a QRP amplifier and a low pass filter.

He didn’t start from square one when it came time to write the code for the RPi. Instead he grabbed an Arduino sketch for the very same DDS and ported it over to Python. The first test signal was his call sign sent in Morse code at QRSS speeds. But he also managed to get Hellschreiber messages working, making it a multiple-mode device.

[via Solder Smoke]

Putting The BBC In Seattle

January 13, 2013 by Brian Benchoff 57 Comments

radio

Among great British traditions, there’s tea, knowing how to lose an empire, tea, Parliament, big ben, tea, incalculable wit, Parliament, big ben, tea, and BBC radio. While Britons in foreign lands may not be able receive BBC radio over the airwaves, there is the remarkable BBC iPlayer that allows online streaming of all those awesome BBC radio stations. Unfortunately, moving away from the Prime Meridian means the BBC radio schedule deviates from the schedule ordained by divine right. In Seattle, for example, a Friday evening comedy would be broadcast in the middle of the afternoon. Basically, it’s like listening to Prairie Home Companion on Saturday morning. It just feels wrong.

[Adam] came up with a clever solution to this problem. Yes, it’s really just a Raspberry Pi-powered web radio, but there’s a twist to this build: everything from BBC radio is buffered and time shifted. A program that airs at noon in London will now play on [Adam]’s radio at noon in Seattle.

The hardware portion of the build is an exceedingly British radio which [Adam] deftly modified to include an auxiliary input. The software portion of the build uses ffmpeg, mplayer, and a PHP script to stream the iPlayer audio to a file, wait 8 hours (or whatever the offset from GMT is), and start playing the audio.

In the end, the time shifted BBC radio works perfectly, and even caught the attention of a few people at BBC Radio 4. [Adam] was interviewed about his project, and was even able to listen to his interview several hours later.