[Travers Buda] is giving new life to his abandoned childhood toys. He cracked open a set of Family Radio Services radios he had received for a birthday which work up to 2 kilometers apart. With just a bit of extra circuitry he was able to get them to act as wireless modems. The system functions but it looks like it would benefit from some more refinement, including error correction. In the end [Travers] manages to send and receive ASCII based messages at a whopping baud rate of 10.
[Erich] rethought the use of a megaphone and ended up with this Mega-Tape-O-Phone. His first move was to ditch the megaphone’s amplifying circuitry in order to add his own based on an LM386 chip. From there a radio receiver joined the party followed by the guts of a tape player. He relocated the head of the tape deck to the end of a flexible cable and coated the outside of the megaphone bell with magnetic tape. Now he’s surfing the airwaves and scratching away happily.
The use of the tape head has been seen here before, but it was never in a mobile package like this is. Join us after the break for some video of this in action.
[Alex] had an old FM radio tuner card come his way. It used an ISA connector, a standard that went the way of the dodo in the mid-nineties. With the challenge of implementing an ISA-bus to configure the card he set out on his mission. What he came up with is a working radio using the ISA card and driven by a PIC 16F877. Join us after the break for schematic, code, and a few details. Continue reading “Resurrecting ISA Hardware”
In keeping with our opinion that radio operators were the original electronic hackers here’s a guide to building your own transmitting air variable capacitors. Using some roof flashing, Plexiglas, and various fasteners [David Hammack] was able to make it work. It’s not a perfect solution but he has some ideas to make the next one better. Give this a try after you’re done tweaking your crystals and building input devices.
[Thanks Rich]
[W1VLF] is on a quest to communicate over long distances with a 9 kilohertz transmitter. He built this giant coil with that in mind. A round concrete form was used as a base and wound with magnet wire by hand. We’d recommend building an automated winding device, but this method seems to have worked. Operating at 50 Watts on the air-core coil at 8.97 KHz he was able to pick up the signal at a distance of 5 kilometers. It’s not breaking any overall distance or portability records, but on a project like this the quest is where the fun is at.
[Thanks Drone]
If you’re interested in learning about Very Low Frequency communications take a look at what Larry has to offer on his site. He’s put together a guide to VLF receivers that is short enough to read and clear enough to understand with rudimentary knowledge of circuits. He builds a simple receiver as a working example and a high-powered transmitter that can put out over 2600 watts. Let’s face it, radio operators were the original electronic hackers. Get back to our roots and learn the ways of the transistor.
[Thanks Buddy]
It’s got a NIC, a remote, a character display, and can record and play back streaming audio. Thumper is [Harrison Pham’s] contest-winning Internet radio player.His finished board is roughly the same size as the 16×2 character display and piggy-backs the device for a small form-factor. It can be controlled via an infrared remote control, or through a remote web interface. Source files are available from the link at the top, but the really juicy details are included in the shockingly comprehensive PDF writeup.
The photo above is a bit misleading. The board has a micro SD slot on the back even though a USB card reader is shown. This project would need USB host control for Propeller chips in order to use that reader. Don’t forget to check out some of the other submissions to the the contest once you’ve had your fill of this one.
[Thanks Drone]
