When [Caleb Kraft] was in full production for Hackaday he pumped a pile of awesome videos. But not every project worked out. He’s been a fan of the Fail of the Week posts, and sent in his own recollection of a project gone wrong. Above you can see his phosphorescent CD player. He prototyped the project in May of last year but technical issues and looming deadlines meant it never saw the light of day. We’ll fill you in on his fail after the jump.
Editor’s note: We need more tips about your own failure! There are a handful of submissions left in our reserves, but to keep this topic as a weekly column we need help tracking down more failed projects. Please document your past failures and send us a link to the write-up. If you don’t have a blog to post it on you may do what [Caleb] has done and email us directly. Remember to include any images and links to video which you may have.
The gist of the project is that [Caleb] wanted to use an LED to charge up some glo-in-the-dark paint. The easiest mechanical setup he could think of was to use an optical drive, with the disc itself as a moving display, and the lens sled as a way to move the light source. [Caleb's] own words tell of the successes and failure he encountered:
Hey Mike and gang, let me start out by saying that I really love the new direction of the site. You guys are kicking some serious butt in my opinion. One of the new things I really love are the Fails. I thought I would share a fail from my time there at hackaday, a project that didn’t get very far, but I think has some really cool potential.
As many already know, I’m a little obsessed with glowy things. I was really inspired by the Ghost Matrix and immediately started thinking of things I could do along similar lines.
What I came up with, code named Enceladus for no apparent reason, was going to be a Compact Disk sized glowing visualization.
In the beginning, things were looking good. I grabbed the clear protective CD off the top of a stack, scuffed it up, and sprayed it down with glow in the dark spray paint. It cracked a little, but I didn’t care since this was going to be a proof of concept. I ripped the carriage out of a CD player and replaced the laser with an LED. At first I used a white one, then I ran to the store and bought some UV LEDs
I thought it looked good enough to continue. So I did! I fixed the LED spacing issues so it wouldn’t rub. Then I added controls for moving the LED as well as controlling PWM on the spindle motor.
At this point I found that the poor motor couldn’t handle low speed at all. It was fast or nothing. I had intended to rip it out and put a stepper motor in there for much better control, but got distracted by my almost coast to coast hackerspace tour that summer.
I’m pretty sure I tossed the hardware a long time ago, but this is a project I wouldn’t mind revisiting in a more refined manner in the future.
The failure here is actually quite similar to the one that we featured last week. The issue is that the CD needs to move slowly enough for the UV LED to “charge” up the phosphors. It also needs to be accurate enough to achieve some type of meaningful resolution. We’d like to know your thoughts on this project. Is a stepper motor replacement the best way to go, or could this be driven reliably with the right brushless motor controller? Even if the motor control was sorted out do you think the single light source will be able to charge the phosphors fast enough for a message to be read before the glow material fades back to normal?
Fail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.