Radio Cabinet Media Center

October 17, 2009 by Mike Szczys 26 Comments

old-time-radio-mediacenter

[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.

Polycarbonate Fish Uses Three Servos To Swim

October 17, 2009 by Mike Szczys 15 Comments

polycarbonate-fish

[Amnon] is learning the hard way that water and electronics don’t always like to play nicely together. He’s been working on creating a swimming fish that uses three servos to flex a sheet of fish-shaped polycarbonate. This photo doesn’t really do the project justice but you can get a better idea of what he’s accomplished by watching the videos after the break.

The three servos along with some distance sensors for obstacle avoidance are all controlled by a PIC 16F877A microcontroller. [Amnon] tried out three different waterproofing methods; coating the device in varnish, dipping it in hot glue, and dipping it in epoxy. The first two resulted in water damage to the electronics, but the third managed to work. It kept the water out, but also prevents reprogramming of the controller.

Although not successful, we would have loved to see the process of dipping the fish in a churning vat of molten glue. Once perfected, this may be the perfect platform for carrying our weapons of doom.

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Adding A Keypad To A Key Card Lock

October 9, 2009 by Phil Burgess 19 Comments

keypad

[Colin Merkel] had a little problem: he was continually forgetting his electronic key card, locking himself out of his own dorm room. Like any normal Hack a Day reader, rather than getting in the habit of always carrying his card, the natural impulse of course is to build this elaborate rig of electronics and duct tape. Right?

The result is an additional keypad that can be used to gain access…not by altering the existing electronic lock, but with a secondary mechanism that operates the inside door handle. An 8-bit PIC microcontroller scans the outside keypad (connected by a thin ribbon cable), and when a correct access code is entered, engages a 12 volt DC motor to turn the handle. It’s a great little writeup that includes a parts list, source code, and explains the process of keypad scanning.

It’s similar to the RFID-based dorm hack we previously posted. By physically operating the handle, most any approach could be used: facial recognition, other biometrics, DDR pad, or whatever inspired lunacy you can dream up.

Touchscreen Picture Frame

September 29, 2009 by Mike Szczys 9 Comments

touchscreen_picture_frame

Circuit Ideas Design has posted a digital picture frame project based on their 240×320 16-bit color QVGA display. We made our own digital frame from a smaller screen a while back and this is pretty much the same implementation except with a larger screen and built around the AVR family of microcontrollers rather than PIC controllers.

The thing that piqued our curiosity was the five icons silk screened on one end of the display. That’s right, this is a touch screen. The board also has a built in SD slot and a bit of flexibility for connecting to a microcontroller. It can be controlled from a 40-pin header, or from headers that are designed to work as an Arduino shield. We’d love to get our hands on one but we were unable to figure out what currency the list price was in. Has anyone used this board yet?

Tool Tip: Microcontroller Timer Calculator

September 28, 2009 by Mike Szczys 11 Comments

uC_timer_calculator

In life and embedded systems timing is everything. Give [Frank’s] web-based timer calculator a try. Set your system clock resolution (in hertz making sure you account for any system clock divider), select your timer resolution and prescaler, then calculate based on desired ticks, overflows, or real time. He’s built this with the AVR chips in mind but it should be handy for any family of microcontrollers.

Of course none of this is rocket science, but if you’re trying to use one timer for two differently synchronized events this can save you a lot of trial and error time.

Capacitive Buttons Control All Life

September 28, 2009 by Mike Szczys 7 Comments

capacitive_game_of_life

Projects involving Conway’s Game of Life and utilizing a Nokia 3310 screen are quite popular with electronics hobbyists. [Droky] put these two together and went one step further by adding capacitive sensors to control the Game of Life. His work is a great example of how to use the Atmel QTouch capacitive sensor (QT100a datasheet). This chip does the heavy lifting that we’ve seen in other touch sensitive solutions. It operates from 2V-5.5V, requires only three capacitors and a resistor, has a one pin active high output, and sells for around $1 in low quantities. One thing [Droky] overlooked in his board layout is the ground pad on the bottom of the WSON6 chip. He was able to make it work by masking the trace that runs under the chip but you will want to alter the layout in your own designs.

If you’ve used the QT100a before we’d like to hear about your experience, and find out if button debounce handling is necessary with this chip. Let us know in the comments. You can see a video of it in action after the break.

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Word Clock: Tell The Time With Words

September 27, 2009 by Gerrit Coetzee 24 Comments

[drj113] posts his cool word clock. After seeing a similar clock on an industrial design website, he set out to make his own version. He made custom pcbs with the toner-etch method. The front is a solid piece of copper clad board and the light shines through the etched areas. It’s powered by a PIC microcontroller and uses approximately 120 ultra bright LEDs. [drj113] has all of the circuit board diagrams, silkscreens, etch negatives, and code on the intructable so you can build your own.