classic hacks

2822 Articles

Poddwatt: Tube Amp With Mp3 In Mind

October 23, 2009 by 41 Comments

poddwatt

[Bruce] has designed a push-pull tube amp that has enough gain to connect to a portable audio player. The design is closely related to his OddWatt offering from a few years ago. The new amp has many redesigned circuits and the new hardware choices drop the price tag of the parts by about $50.

This little wonder pumps out 5-7 watts and [Bruce] is please with the end result. It doesn’t put out quite as much low-end as the KT88 amp we saw last year, but compared to some other iPod speaker solutions this provides stellar audio.

Reverse Geocache Puzzle

October 19, 2009 by 32 Comments

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[Mikal] wanted to create an awesome electronic wedding gift for his friend who was moving to France. After experimenting with a few things, he settled on creating a puzzle box that would only open in a certain location. Since his friend introduced him to the Arduino, he fittingly used one in the design, along with a serial GPS module and a mini character LCD. The box itself is locked using a servo-controlled chopstick, which could theoretically be snapped if [Mikal] really screwed something up. To save battery life, he used a small Pololu module to provide power that uses only 0.01 microamps in standby, and can be shut off by the Arduino.

The box was designed to be mysterious yet self-explanatory. When the button on the front is pushed, the box comes to life for 3 minutes, displaying the distance away from secret location. Additionally, it warns how many tries are left: the button can only be pushed 50 times before it is sealed “forever”. In order to open the box, you have to be within 2km of the destination. Theoretically, you can narrow down the location to one of 2 points after 2 readings, but a less scientific approach would probably be a lot more fun.

This seems like an amazing gift, and the same concept could be repurposed into hundreds of other devices. For extra fun, he could have placed it at a geocache location.

Radio Cabinet Media Center

October 17, 2009 by 26 Comments

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[Jon] picked up an old Philco radio from a pawn shop for $81. The electronics were shot and the controls had seen better days. So he set to work giving this old beast a makeover, turning it into a beauty of a media player.

The face plate for the controls had seen better days. His solution was to replace it, which gave him more options for mounting a display and controls. A menu system was implemented on the LCD display using a PIC18F4450 microcontroller. The chip also takes care of the three rotary encoders for the user interface and integrates the whole thing with the PC backend.

We’ll be the first to admit that a full PC is overkill in this situation. That being said, this was slow, unused system that is seeing new life. But is it worth the added noise and energy costs? Who knows, we think this leaves a lot of room for future revisions. Perhaps an NAS and wireless controls via iPhone or a similar device?

We’re a bit disappointed that [Jon] didn’t do some work to get better sound out of this. With a great big cabinet like this, the right speakers with a tube amp will produce some sweet sound. Certainly most things would be better than just using a pair of computer speakers. We’ll keep our eye out for an update that adds a tube kit to the project.

72 LED Persistence Of Vision Globe

October 15, 2009 by 34 Comments

HaD-pov-globe

[Ben] told us about his POV globe yesterday. We took a look and saw just one photo and the code with no real explanation of his project. He certainly set to work over night and now we see all the goodies we look for in a great build log. He even threw the Hackaday logo up for our enjoyment. His build is well executed and he found some creative ways around the common problems in these projects. We take a closer look after the break. Continue reading “72 LED Persistence Of Vision Globe” →

Finally, A Keyboard For The IPhone

October 14, 2009 by 31 Comments

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We can’t say we’ve had problems typing on our iPhones here at HackaDay, must be the elfin fingers, but for [Ben Kurtz] it was a real pain. The obvious solution is to carry around an Arduino, 9 volt battery, iPhone breakout board, a ps2 keyboard, and of course the iPhone itself. Well, maybe it could be a little smaller with fewer parts, but at least it works. The Arduino reads input from the keyboard and converts it to serial, then the iPhone pulls the data via VNC. Like we said, a little roundabout, but we love the amount of ingenuity involved.

Jamin’ To Bach, Commodore 64 Style

October 13, 2009 by 25 Comments

[youtube=http://www.youtube.com/watch?v=MOhzkWZHBfM]

[thrashbarg] missed the sounds of the Commodore 64 and longed to hear the great masters in 8-bit glory. To get his fix, he created a midi device using the original Sound Interface Device from those long-dead systems. He’s interfaced the MOS6581 SID with an Atmel AVR ATmega8 microcontroller. The receiving pin for the AVR’s UART is used as a MIDI-IN connection, with the microcontroller converting midi data into the proper sound generation specs for the SID. The result is the 10 minutes of [Bach]’s Brandenburg Concerto heard in the embedded video above.

We have no idea where he picked up this obsolete chip, but if you want to give this a try, perhaps you’ll have some luck emulating the MOS6581 by using another ATmega8.