Internet Radio Occupies An 80-year-old Radio Case

November 28, 2012 by Mike Szczys 26 Comments

[Florian Amrhein] made use of some old hardware to build his own internet radio in a 1930’s radio case.

The original hardware is a tube-amplified radio which he picked up on eBay. There’s tons of room in there once he removed the original electronics and that’s a good thing because he crammed a lot of new parts into the build. The main one being an old laptop he had on hand. It’s got a 10″ screen which is too large for the opening, but that ended up being okay. He coded an interface with C and SDL which give him a visual representation of his favorite online streams. The knob to the right moves the red line when turned and causes the Debian box to change to the new stream using the Music Player Daemon. Two potentiometers control the tuning and volume, and there is also a rotary encoder which is not yet in use. All three are connected to the laptop via an Arduino.

Check out the finished product in the video after the break. It sounds quite good thanks to the small automotive speaker and amplifier also crammed into the old case.

If you don’t have a laptop lying around to use in a project like this consider a microcontroller and character LCD based system.

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How To Build Your Own Dedicated Pandora Radio

September 20, 2012 by Mike Szczys 18 Comments

This mix of modern and retro acts as a standalone Pandora client. It’s certainly a radio upgrade, falling somewhere in between the passive listening of traditional broadcasts, and the complete control of music players that use playlists.

Inside the wooden case a BeagleBoard does most of the work. It’s running Ubuntu 12.04 on which pianobar, a command line interface package for Pandora is running. Those components alone would make a pretty nice listening experience, but since Pandora rolls different music into the mix it’s nice to be able to see what you’re listening to. The four-line LCD is wide enough to display plenty of information. It’s being controlled by a PIC24 microcontroller which also monitors the controls on the top. As you can see in the video after the break, the user interface offers almost everything you could want. It’s easy to switch stations, and you can still register your preferences on each track being played.

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A Laser Audio Transmitter

August 31, 2012 by Mike Szczys 38 Comments

Here’s a way of transmitting audio that makes it virtually impossible for someone else to listen in. Instead of sending radio waves bouncing all over creation, this uses the focused light of a laser to transmit audio. In the image above you can see the silver cylinder which houses the laser diode. It is focusing the beam on a light dependent resistor to the right which looks almost like a red LED due to the intensity of the light.

The simplicity of this circuit is fascinating. On the receiving end there is no more than the LDR, a 1.5V power source, and a headphone jack. The transmitter is not much more complicated than that. It includes an audio output transformer which boosts the resistance of the audio signal. This increase in resistance ensures that the laser diode modulates enough to affect the LDR on the receiving end. The transmitter uses a 3.3V supply. Check out the video after the break to hear the high quality of audio coming through the setup.

Once you’re done playing around with the transmitter you might try turning the laser into a remote control for your stereo.

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More Small Radio Modules For Your Wireless Needs

August 23, 2012 by Brian Benchoff 18 Comments

In the never-ending pursuit of cheap wireless communication for your microcontroller projects, [kiu] came up with a small board that allows for serial communication via a 433MHz radio link.

[kiu]’s transceiver uses an RFM12 wireless module available online for just a few dollars. Alongside this module is an ATMega8 and a USB to serial FTDI chip. When [kiu] plugs this board into his computer, he’s able to run a terminal, connect to this board, and receive and transmit hex values at 115,200 bps from another one of these boards.

According to [kiu]’s BOM, 10 boards only cost him 180 Euros, or about $225 USD. Considering off-the-shelf solutions such as an XBee could easily cost twice as much, we’re thinking [kiu] did a very nice job here.

[kiu] put all the board files, schematics, and code up on his GitHub, ready for your perusal. A very cool build, and very useful for a high altitude balloon, rocket, or wireless sensor build.

Controlling A Quadcopter With A Homebrew Remote

August 22, 2012 by Brian Benchoff 15 Comments

When [Matt] started building his multirotor helicopter, he was far too involved with building his craft than worrying about small details like how to actually control his helicopter. Everything worked out in the end, though, thanks to his homebrew RC setup built out of a USB joystick and a few XBees.

After a few initial revisions and a lot of chatting on a multirotor IRC room, [Matt] stumbled across the idea of using pulse-position modulation for his radio control setup.

After a few more revisions, [Matt] settled on using an Arduino Pro Mini for his flight computer, paired with a WiFly module. By putting his multicopter into Ad-hoc mode, he can connect to the copter with his laptop via WiFi and send commands without the need for a second XBee.

Now, whenever [Matt] wants to fly his multicopter, he plugs the WiFly module into his MultiWii board, connects his laptop to the copter, and runs a small Python script. It may not be easier than buying a nice Futaba transmitter, but [Matt] can easily expand his setup as the capabilities of his copter fleet grows.

Video of [Matt]’s copter in flight after the break.

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Very Inexpensive RF Module Tutorial

August 19, 2012 by Brian Benchoff 39 Comments

Let’s say you need a way to make a project wireless, but don’t have the scratch for a ZigBee or its ilk. You could use IR, but that has a limited range and can only work within a line of sight of the receiver. [Camilo] sent in a project (Spanish, translation) to connect two devices via a wireless serial connection. As a small bonus, his wireless setup is cheap enough to create a wireless network of dozens of sensors.

[Camilo] used the TLP434A transmitter/receiver combination to get his wireless project off the ground. These small devices only cost about $5, but being so inexpensive means the hardware designer needs to whip up their own communications protocol.

For a microcontroller, [Camilo] chose a Freescale MC9S08QC, a pleasant refrain from the AVR or PIC we normally see. After making a small board for his transmitter, [Camilo] had a very small remote control, able to send button presses or other data to a remote receiver.

After the break, you can see a short demo video [Camilo] posted of his wireless transmitter turning on an LED attached to his receiver. Unfortunately, this video was filmed with a potato, but all the schematics and code is on his web site for your perusal.

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Ancient Radio Repair

July 6, 2012 by Mike Szczys 39 Comments

They sure don’t build them like that anymore. [J.W. Koebel] managed to take this 1934 Simplex Model P radio and bring it back to life.

So where do you start with a repair job like this one? Being a ham radio guy he has a good idea of what he’s doing, and started by replacing the AC capacitor with one which will provide quality noise filtering. He tried to make fixes throughout that would improve functionality and declutter the wire mess. This led him to find a snapped solder connection on the volume knob. Next he tested out the speaker and found that the primary transformer needed replacing. After as replacing the A67 converter (we’ve got no idea what that is) he swapped out the rest of the original capacitors, most of the resistors, and fixed the mechanical problems with the tuning dial. The result is a working radio that looks fantastic!

[via Reddit]