GD Drive schematic

Wednesday, February 4, 2009
Ok so I got the CD-Drive working. For a while now I have been trying to figure out how I was going to get it working and had a few ideas and built a couple prototypes and have finally settled on one that works completely. It uses two 555 timers and 4 sensors, and one button to open and close the drive.

From Dreamcast Laptop

Here is the schematic.

So basically how it works is you have one of the 555's to control when the tray goes out and the other for when it goes in. The 555 that makes it go out, you put the switch/sensor connected to pin 2 of that 555 on the closed side of the tray so that when it is closed it pushes the switch. Put the switch that is connected to pin 4 on the open side so that when it is open it pushes the button/switches the switch.

Then for the 555 that closes it do the opposite. Put the switch connected to pin 2 on the open side and the switch connected to pin 4 on the closed side. Basically what happens is when it is closed you push S1 and that triggers the open 555. When it is open it pushes pin 4 of the opening 555 and resets it sending it back to 0v. It pushes the button connected to pin 2 for the closing 555 so when you push S1 it triggers the closing 555. When it is completely closed it pushes the switch connected to pin 4 of the closing 555 and it sends it back to 0v.

One of the problems I had with this at first was I didn't have the capacitors on it at first and for some reason the circuit would work until I hooked the motor up to it and I'm thinking that the motors induced voltage after it got shut off would cause the 555 that performed the direction opposite to the way it was going (so when it got completely opened it would instantly trigger the closing 555 and begin to close). This would go on endlessly until you took away the power. So I was trying to think of a new way to do it and then I thought about putting in the two capacitors and it worked. Later on I had to switch out the capacitors for some larger 3300uf ones instead because 1000uf didn't seem to be enough. Hooked it up to 12v and all worked.

Video of it working.


JOSHUA said...

Instead of using two 555s you could had used a 556- it has two 555 timers on one chip.

Matthew Sessions said...

this is true. I knew that there was a 556 I just didn't even think about using it. Although when I was testing I'm glad I had seperate 555's because I fried a few in testing and so it was good to just be able to switch out one instead of having to switch out a 556.

Brad said...

What sensors did you used in the circuit?

kyle said...

What do the sensors even do? Can't i just put the disk close switch on the back where when the disk close switch is in the closed position? Or how about a couple of tacts?

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