radio

570 Articles

Plantenna: The Plant Antenna

October 20, 2010 by 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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Building A Crystal Oven

September 28, 2010 by 13 Comments

Radio communications depend on stable oscillator frequencies and with that in mind, [Scott Harden] built a module to regulate temperature of a crystal oscillator. The process is outlined in the video after the break but it goes something like this: A small square of double-sided copper-clad board is used as a base. The body of the crystal oscillator is mounted on one side of this base. On the other side there is a mosfet and a thermister. The resistance of the thermister turns the mosfet on and off in an attempt to maintain a steady temperature.

This is the first iteration of [Scott’s] crystal oven. It’s being designed for use outdoors, as his indoor setup uses a styrofoam box to insulate the oscillator from ambient temperatures. He’s already working on a second version, and mentioned the incorporation of a Wheatstone bridge but we’ll have to wait to get more details.

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Codec2: GNU Low-bitrate Speech Codec

September 23, 2010 by 11 Comments

Low bandwidth speech compression is a desirable concept for amateur radio enthusiasts. Unfortunately there isn’t a great open-source option out there, but that’s changing with the low-bitrate speech compression package called Codec2. It manages to transmit and decode at 2550 bits per second with results comparable to proprietary solutions like MELP and very near the initial goal of 2400 bit/s. [David Rowe], who spearheads the project, has been simulating communications using a Linux box and has posted audio snippets at the first link above for comparison. They’re looking for feedback and testing so if you interested give them a helping hand.

[Thanks Robomo]

Small And Simple FM Radio

September 21, 2010 by 23 Comments

[gpsKlaus] built this little FM radio (translated) based on the AR1010 IC. That chip is controlled via I2C by an ATtiny45 microcontroller. His tuning implementation relies on presetting 16 stations in the firmware and selecting them with the white potentiometer.

The FM chip came on a breakout board from SparkFun. Not bad at around $15 as it includes the crystal, some caps and a few resistors, and you don’t have to try and solder to the fine pitched pads on that minuscule package. We’re a little unsure of the features included in the part as the datasheet is lacking in detail and the reference datasheet that SparkFun includes in the description is obviously for a much more full-featured chip. Still, this would be a fun thing to play around with if you’ve grown tired of blinking LEDs.

If you don’t want to let an integrated circuit do all the heavy lifting try this post for a guide on building your own radio tuner.

1953 Radio Includes Tubes, AM, FM, And MP3

September 7, 2010 by 16 Comments

This vintage radio can play AM, FM, and MP3, all with a classic sound. Inside you’ll find a new AM radio tube-amp, providing the functionality you’d expect from the device. The rest of it comes from a conglomeration of parts; an FM receiver board from another radio and an MP3 player with remote control and USB connector. The classic sound we mentioned above comes from an AM modulator. That’s right, the auxiliary audio boards aren’t connected directly, but are broadcast on the AM band so that your latest MC Lars album has the same sound quality as the traffic report.

Check out this similar project from last year that adds RDS to a vintage radio.

Adding A Microphone Jack To A HAM Radio Handset

August 8, 2010 by 18 Comments

[dajjhman] wrote in to show us how he added a microphone jack to the handset of his Yaesu radio while retaining the DTMF functions. He states that there were some adapters available on the market, but they are non standard and didn’t really fit his needs. The modification itself is pretty simple, especially with his great documentation and clear pictures. For anyone else who might need this setup, this should be a great resource.

Hackaday Links: July 25, 2010

July 25, 2010 by 20 Comments

Radio Receiver

If you never got the chance to build one as a kid [JoOngle] takes you through the steps to build your own radio receiver. Details are a bit scarce but it’s nothing your friend Google can’t help you out with.

Fixing a Blackberry trackball

If your Blackberry trackball stops working well you can try this non-technical fix. Remember when mice used to have a ball in them and you would need to clean out the gunk from time to time? Forcefully skidding your Blackberry across a piece of paper does a similar service.

Linux time lapse

Open source can be a great help to small businesses. Here’s a way to use a Linux machine to make time-lapse movies from surveillance camera feeds. We especially enjoy the use of a desktop wallpaper that has the terminal commands necessary to start recording.

Host a webpage with Dropbox

Here’s a way to host a simple webpage using Dropbox. It’s one of those easy ideas that you wouldn’t come up with yourself. When you place an HTML file in your Dropbox you can get a public URL which will be built as a webpage when visited with a browser.

Inline splicing

To round out the weekend here’s [Osgeld’s] tips on inline wire splicing. We laughed as he recounted spearing himself with stray strands. This is pretty simple stuff but he’s explained it well and who’s to pass up a good tip?