Trash To Treasure Bluetooth Radio And Tube Amp Build

September 22, 2013 by Mike Szczys 8 Comments

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The before image doesn’t look all that bad but we were still impressed with what went into the restoration of this radio. Perhaps restoration isn’t the right word since it didn’t manage to hold on to any of the original internals. This is more resurrection of a retro radio case for use as a Bluetooth radio.

At first look we didn’t notice that the original knobs were missing. The speaker fabric is ripped and the glass on the tuning dial is broken as well. [Yaaaam] happened to have another antique radio with interesting knobs — but he didn’t just transplant them. He made a mold of one knob and cast three replacements for the radio. After refinishing the wood he replaced the fabric and things were really starting to look up.

All of the electronic components were removed and a new tube amp was built on the original metal chassis. It uses a Bluetooth module for input which facilitates using your smart phone as the playback device without involving any wires or other nonsense. Two problems popped up after the project was completed. The first replacement power supply overheated. The second replacement had a different problem, needing some additional shielding to prevent noise from creating unwanted… noise.

This looks so much better than modern injection molded plastic shelf systems. But there are some fun wireless hacks out there for those too.

Talkbot: An Arduino-driven Robot For Beginners

September 21, 2013 by Marsh 5 Comments

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It isn’t exactly WALL-E, but [Bithead’s] affordable introduction to robots — Talkbot — is made out of a trash can. This little guy runs off an Arduino and comes packed with features, including a voice chip, a motor shield, and a pair of bump sensors. Talkbot will cruise around until a bump sensor slams into an obstacle. One of his prerecorded messages will then play through the speaker while he backs up, turns, and tries to find a clearer path.

According to [Bithead’s] build log, tracking down the right bargain voice chip was a bit of a hassle; he skipped over the text-to-speech options only to be stalled by vendor issues. He finally settled on a clone of Sparkfun’s WTV020SD chip sourced from eBay, which allows you to access pre-recorded WAV files stored on a Micro-SD card. The robot’s body comes straight off the hardware store shelf, with PVC pipe for arms and a polystyrene base to hold all the parts. At the bargain price of $110, [Bithead’s] students will have a true hacker experience cobbling the Talkbot together rather than using a prefab kit.

Be sure to see Talkbot in a video below, performing either his green-eyed “friendly mode” or red-eyed “grumpy mode,” which dictates how pleasantly he responds to obstacles. Need something more advanced? Check out the tentacle robot, just in time for Halloween.

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The Difference Between Bitcrushers And Sample Rate Reducers

August 25, 2013 by Brian Benchoff 23 Comments

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If you look around a few electronic music forums, you’ll see a lot of confusion over the difference between a bitcrusher – a filter that reduces the bit depth of an audio signal – and a sample rate reducer – a filter that does exactly what its name implies. With the popularization of 8-bit and retro synth music, this difference is obviously of grave import of concern to saints and kings alike. [Michael] is more than happy to walk us through the difference with real-time sample and bit rate adjustment with his audio hacker board.

The audio hacker board is an Arduino shield with a 12-bit DAC and a 12-bit ADC. With two 1/8″ jacks and a pair of pots, [Michael] was easily able to whip up a sketch that is able to adjust the sample rate and bit depth of an audio signal in real-time.

Contrary to nearly everyone’s opinion of what ‘8-bit’ music is, it’s actually the sample rate that makes music sound like a cassette deck jury rigged into a Nintendo Entertainment System. Reducing the bitrate just makes any audio source sound louder and worse.

Check out the excellent demo video of the effect of bitcrushers and sample rate reducers below.

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Boominator Solar Stereo Keeps The Music Pumping Even In Cloudy Weather

August 12, 2013 by Michael Ciuffo 22 Comments

Despite 40-some years of product improvements, boomboxes today still require a half dozen D-cell batteries and measure their life in single digit hours. After this, the batteries get chucked in the trash. Tired of the absurd cost and quantity of batteries required in a typical boombox, reddit user [anders202] has whipped up a solution that will keep the party going and the landfills empty. Using some off-the-shelf components and some impressive woodworking skills, he created the “Boominator”.

Despite its environmentally-conscious design, this green machine packs a whallop. Using its dual 10W solar panels, it can drive four woofers and tweeters to produce an estimated 102dB of sound with power to spare. This extra juice can be used to charge its two internal 7.2Ah batteries or a cellphone using the integrated USB charging ports. Better still, Anders chose amorphous solar panels (as opposed to crystalline) which produce power even in cloudy weather as demonstrated during a cloudy day at the Roskilde festival in Denmark. For more information, check out the reddit comment thread.

Video demo after the jump

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I Keep My Tunes In An Ammo Can

July 27, 2013 by Mike Szczys 18 Comments

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Calling this a boom box is at least slightly ironic. Instead of high explosives it now carries high decibels in its new life as a self-contained sound system.

Despite the conspicuous power cord a peek inside reveals a big enough battery to keep the tunes playing for hours on end. [King Rootintootin] kept the cost on the build down since he was given the used speakers and amp by his girlfriend’s dad. The amp kicks out about 25 Watts with the battery rated at 7.2 Ah. He added a charger and routed the controls to the side of the ammo box so that it can be charged without removal. The only external component is the audio jack which connects it to the music source.

One of the suggested improvements from the Reddit thread is to add baffles inside of the enclosure so that sound from the two stereo channels doesn’t interfere with each other.

Simple Looking Antique Internet Radio Has A Lot Under The Hood

July 14, 2013 by Mike Szczys 28 Comments

rpi-internet-radio At first glance you might not even notice that this 1934 radio has been altered. But close study of the tuning dial will tip you off that changes have been made. It still scrolls through stations just like the original. But it’s not a wheel with some numbers on it. The rotary motion is an effect produced by an LCD screen.

This is the second time we’ve seen one of [Florian Amrhein’s] Internet radio projects. The first used guts from a Laptop paired with an Arduino to pull everything together. This time he’s chosen to wield a Raspberry Pi board. It feeds a USB sound card for a bit better quality. A small amplifier board us used to power one large speaker behind the original grill of the radio.

Check out the demo video to see that radio dial in action. It’s delightful that he went to the trouble to emulate a rotating disc to keep with the theme of the project.

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Car Stereo AUX Input Taps Into CD Ribbon Cable

June 28, 2013 by Mike Szczys 50 Comments

[Gezepi] wanted to add an auxiliary input to the stereo in his 1994 Camry. At first look there wasn’t an easy way to patch into the system. But a bit of probing with an oscilloscope and figured out that he could inject audio through the CD ribbon cable shown above. The CD reader is a self-contained unit that receives commands through the cable, and passes analog stereo audio back to the receiver portion of the head unit. We’re not sure how he figured out which pins to tap into, but it may have been as easy as probing with some headphones while a CD is playing.

The extent of his hack is documented in the image below. He cut the two audio leads on the CD side of the ribbon cable, then soldered his auxiliary jack on the receiver side of the cable connector. This ensures that two audio signals aren’t being piped into the receiver at the same time. Unfortunately it also means that he won’t be able to use the CD player. We have seen other methods that use a special audio jack as a pass-through which cuts the connection when a jack is inserted. That’s the method used in this Subaru hack.

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