RFID-based HTPC Controller Gets A Wireless Refresh

March 20, 2011 by Mike Nathan 4 Comments

RFiDJ_Refresh

[roteno] recently wrote in to let us know that he has completed work on the RFiDJ Refresh, a follow up to his 2009 project, the RFiDJ.

The concept is pretty simple – he has a set of RFID enabled tiles, which contain references to particular online streaming audio stations. He uses these tiles to tune into audio feeds on his HTPC by placing them on a block containing an RFID reader.

His previous implementation had the RFID reader tethered to his HTPC, which didn’t make it all that convenient to use. The newer version utilizes a 433 MHz transmitter/receiver pair in order to communicate with the PC, so it can be used anywhere through out his house. The reader and transmitter were placed in a shadow box picture frame, along with a rechargeable Li-poly battery that powers the whole setup. He also mentions that he has added a tactile interface that allows him to initiate mobile phone calls from the RFiDJ as well.

It’s a nice update to an already great project. We imagine it’s a bit more fun for [roteno] and his guests to tap a coaster on the transmitter box than fumble with a remote to change radio stations on the HTPC, but that’s just us.

Check out the videos below to see his new setup in action.

Continue reading “RFID-based HTPC Controller Gets A Wireless Refresh” →

Pitch Shifter Makes Your Band Sing Higher

March 17, 2011 by Mike Szczys 23 Comments

[Markus Gritsch] tipped us off about this little module he built to shift the pitch of audio playback. It uses a PIC 24FJ along with a couple of LM386 amplifier chips to manage the input and output signals. At the push of a button, audio being fed through the device can be modulated to a different key without changing the playback rate. Here it’s being used with a iPod but because this device just sits between an audio source and a signal input we wonder if you can have some fun on the cellphone with this circuit?

Check out the video after the break to hear it in action. We must compliment [Markus] on his layout. We haven’t seen the underside of that protoboard but he’s done a great job of fitting everything into a small area. You can find the schematic for the circuit by following the link at the top of this feature. He took a picture of his hand-drawn plans which saves him time from laying it out with something like KiCAD but still gives us the details that we love to see with your projects.

Continue reading “Pitch Shifter Makes Your Band Sing Higher” →

CD Phonograph Brings Old-time Charm To Modern Music

March 13, 2011 by Mike Nathan 23 Comments

phonograph

[Jozerworx] had always wanted to build a CD player that looked like an old-time Victrola Phonograph player, though he never seemed to be able to find the time to do it. With all of his other projects out of the way, he decided to finally get started on building his phonograph.

He went garage sale hunting and found the perfect base for his project – an old wooden box adorned with tarnished brass hardware. He started in on the project immediately, dismantling a cheap CD player and mounting the motor/laser assembly on the top of the box. The CD player internals were installed inside the wooden box, along with a small audio amplifier stripped from a portable iPod speaker.

A brass horn was fashioned out of an ornament, in order to complete the phonograph feel, but also to act as a passive amplifier. He then mounted a series of switches on the top of the box to allow him to control the CD player’s basic functions.

[Jozerworx] says that it sounds decent, though there are some things he would change. He plans on switching out the audio amplifier and possibly the speakers at some point in the future. He is also still keeping his eye out for a larger, and more effective horn.

Personal Soundboard Recounts Years Of Clever One-liners

March 12, 2011 by Mike Nathan 7 Comments

personal_soundboard

[Antibore’s] friend was just wrapping up his Ph.D. Degree and he wanted to build him something special to commemorate the accomplishment. After thinking about it awhile, he realized that his friend was quite gregarious and known to make off-the-wall comments at parties and such. A ton of these one-liners were documented on video over a span of 10 years, so [Antibore] got the idea to make his friend a soundboard featuring his own witticisms.

He found a breakout board capable of playing back OGG files and got to work loading it up with his friend’s random sayings. The board was connected to a small amplifier and speaker, then everything was installed into a black plastic case. Four arcade-style buttons were mounted on the front of the case, along with a picture of his friend. Up to 16 different sayings can be played, depending on which combination of buttons are being held at a particular time.

It’s sounds like a really cool project, and certainly makes for a one of a kind gift. Currently there is no video or audio of the box in action, but here’s hoping we’ll see some soon.

Micro Audio Player Can Hide Behind A Postage Stamp

March 5, 2011 by Mike Nathan 28 Comments

The original iPod shuffle was a pretty small device, there’s no doubt about that. However, in the world of miniature audio players, [Chan] is no slouch either.

A few years ago, he set out to construct a micro audio player that used little more than a small microcontroller and a microSD memory card. He chose an ATinyX5 series microcontroller to run the show, utilizing its pair of PWM output pins to directly drive the speakers. Since there is no built-in amplifier, the audio volume is not loud, but it does sound reasonable if you use a set of high efficiency desktop speakers. He does mention that the sound can easily be amplified after passing the signal through a filter, so there is hope for those of you who like your music turned up to 11.

The only downside we can see is that the audio player can only process Wave files, but it’s hard to expect more from a DIY audio player smaller than a postage stamp. It would be great to see what sort of micro-handiwork [Chan] could perform if he were to update his design and build a full-functioning MP3 player based upon this project.

Bluetooth-enabled Talking Chicken

February 28, 2011 by Mike Nathan 4 Comments

bluetooth_chicken

[Jeri Ellsworth] sent us a video walkthrough of a hack she did a few years ago using a toy chicken with a motor operated mouth. She wired up a Bluetooth headset’s audio output to a LM386 audio amplifier, which drives the speaker she added to the chicken. The output of the audio amplifier was also connected to a 555 timer in bistable mode to activate the motorized mouth. The motor simply opens the mouth when activated, allowing the built-in spring to snap it shut when the 555 is reset.

Obviously Jeri didn’t send us an old project just for kicks, she wanted to remind all of our readers that the 555 Design Contest comes to a close tomorrow night, March 1st at 11:59 EST. If you haven’t submitted an entry yet, get something started while there is still time!

Keep reading to see Jeri give a quick video overview of her talking Bluetooth chicken.

Continue reading “Bluetooth-enabled Talking Chicken” →

A Trio Of Last-minute 555 Timer Projects

February 28, 2011 by Mike Nathan 5 Comments

[Bob] has been busy lately putting the finishing touches on three different projects that he plans on entering into the 555 Design Contest.

His first entry is a low-power H-bridge, which can be used to drive small servos. While he admits that it is a bit odd to build use a 555 timer to construct an H-bridge, they are cheap and plentiful enough to justify their use. Check out the video below to see the simple H-bridge controlling a servo.

[Bob’s] second entry is quite a bit more complex than his H-bridge. His secret knock detector listens for a pattern of knocks, triggering a relay if the proper cadence is detected. If a knock is heard, the first 555 timer starts, listening for another knock within a specific time range. If a knock is heard during this period, the next timer is triggered, and the process is repeated. Subsequent knocks must be timed correctly, or the circuit halts, waiting for a reset timer to expire before listening is resumed. It’s a bit hard to get the knocks just right, but that should be fixable with a few small tweaks.

The third entry he sent us is a project that is pretty common, though with a somewhat uncommon implementation. Class D amplifiers are often built as low-power headphone amps for personal audio applications. He liked the idea of a Class D amplifier, but wanted to build something with enough power to listen to his music in a small room. To accomplish this task, he looked over the internal block schematics of a 555 timer and constructed a pair of high-power 555 timers himself, using discrete components to mimic those usually found in the 555 package. His results were decent, though admittedly not of the highest quality, and could be tweaked a bit to provide better sound fidelity.

Continue reading to see videos of each project in action.

Continue reading “A Trio Of Last-minute 555 Timer Projects” →