Do It Yourself CD Changer 183
SuperDuG writes "This is a true homebrew solution to saving a few bucks when it comes to cd changers. And to make it even better the whole setup is controlled by none other than linux. Seems like a nice setup to do batch burns without user interaction. Source is provided if you wanted to build your own." Not sure if this is very practical, or even if it would be cheaper than buying a changer, but it sure looks cool.
Other goodies (Score:5, Informative)
Be sure to check out the rest [sentex.net] of his page. Fun stuff.
Re:Made out of wood? (Score:1, Informative)
Home built CD changer contraption (Score:1, Informative)
The mechanicals
My first thought was to come up with something extremely simple, with no electronics. Ideally, the motion of the cd tray would trip some sort of mechanism that would eject the CD from the tray and insert the next one. After months of thinking, I still hadn't thought of a mechanism that had a hope of actually working.
The next idea was to pick up the CD, but how to pick it up? Vacuum came to mind, but that would get complicated, vacuum pump, solenoid valves, and all. Finally I decided to just pick up the CD by the hole, with an expanding finger, shown at right. The finger's end consists of a cone that inserts in the CD hold up to the shoulder. The whole finger is cut in half, and pivoted. The pivot is just to the right of the blue rubber band. Its a nail, which rests in a grove in either half. The rubber band is the only thing holding it together. The solenoid on the right pulls the pieces together on the back, which spreads the front of the finger, and holds the CD by friction fit. The shape of the cone is a bit tricky. It has to be made in such a way that it will hold one CD securely, but never a second. I tweaked the shape of the cone a bit after taking this photo.
the next challenge was moving the head around. It has to go up and down, as well as side to side. Stepper motors come to mind, but they do require a fair bit of electronics to drive, with 4 separate coils that need to be switched. Plus they need very precise timing, and still need some sort of "home" switch. Thinking about this a bit, I realized that plain old DC motors with a few micro switches for sensing key positions would be sufficient. The horizontal travel only needs to stop in three positions. The vertical travel only needs to go all the way in either direction. By making down travel gravity based, I didn't have to worry about mashing the stack of CDs or the tray with excessive down travel.
I mounted the pickup mechanism on a block with a hole thru it. This slides along a shaft for vertical guidance. The wheel to its right winds the string to pull the CD pickup mechanism up. Gravity pulls it down. The pickup, pulley, and gear head motor (hidden) make up the carriage, which slides on a smooth metal rod from an old Selectric typewriter (one of the shafts to hold the pinch rollers. The vertical rod also came from that same typewriter. If you ever get a chance to disassemble a selectric, do it. Its a fascinating marvel of IBM engineering from the mechanical adding machine days.
The metal rod, being very smooth, bears the weight of the carriage without too much friction. The wooden rail along the top is mostly to keep the carriage from tipping either way, and to hold the limit switches.
The carriage is pulled back and forth by a string which is driven by the motor on the left. I hadn't installed the string when I took the photo. The string is wound twice around the drive pulley, which gives more than enough friction to drive the carriage. And even if it does slip a bit, its the switches that the carriage hits that determine when to stop.
The Electronics
I was fortunate enough to have a PCB with some solid state relays on it, of the type "ODC-5" from Potter & Brummfield. Solid state relays are essentially an electronic equivalent of a mechanical relay. However, solid state relays only take about 15 miliamperes at 3 volts to drive, and so can be driven directly from digital logic lines or the PC printer port. This saved me from having to wire up a transistor amplifier to drive the relay coils with, like I did in the past. I also had some input relays. I could have hooked the switches directly to the parallel port, but the isolating relays gave me some flexibility in terms of schematic, and are handy for protecting the printer port. Hard t
Re:Made out of wood? (Score:1, Informative)
http://www.sentex.net/~mwandel/legos/legos.html
Color Coding (Score:5, Informative)
They probably don't teach that particular bit of doggerel any more...
Not really a new idea (Score:3, Informative)
Re:Usefull for a small inde band. (Score:3, Informative)
You can get a brand-new autoloading CD Duplicator (either attached [summationtechnology.com] to your PC or standalone [summationtechnology.com]) for $1500. It will also print and attach the labels.
You can probably find something used on eBay [ebay.com].
It seems to me that $1500 - $2000 is a worthwhile investment if it 1) avoids pissed off fans whose CDs won't play because of errors caused doing this by hand, 2) saves hours wasted in front of a PC, and 3) gives a pro-quality image to the band.
Proper way to do a batch burn (Score:2, Informative)
Not only is he a true hacker... (Score:4, Informative)
1. Rather than buy a printer for his C64 back in the day, he elected to build a home made plotter [sentex.net] and make several improvements along the way. It's quite impressive!
2. Before digital imaging was even remotely on the minds of personal computer users, he constructed a slow but functional low-res scanner [sentex.net] That has to be a hallmark of a true hacker--his creations may not be practical and are of limited use, but they are fascinating and forward thinking.
3. Sometimes hacks really do save money, like this multi-megapixel digital camera [sentex.net] made from a cheap $100 scanner at a time when most decent digital cameras cost 10 times that much. Sure, it took 30 seconds to take a pic, but it served the purpose for non-action photography and when motion was involved it could produce some interesting effects.
(bows down) I'm not worthy....
Re:Color Coding (Score:4, Informative)
Bad Boys Rape Our Young Girls But Vilot Gives Willingly, sometimes for Gold, some times for Silver, and sometime for No Charge at all.
Value:
- Black - 0
Tolerance:Brown - 1
Red - 2
Orange - 3
Yellow - 4
Green - 5
Blue - 6
Violet - 7
Gray - 8
White - 9
- Gold - 5%
color1 + color 2 * ( 10 ^ color3 )Silver - 10%
None - 20%
color4 - Tolerance