Motorized Case Side! Man!

[Dr. Kamolly]

Here is a fantasy of mine, a motorized glissening side of a case that opens when you hit the power button at one end revealing LED fans and UV painted speakers.

Something like the steroes in the back of the cars at the beginning of "2 fast 2 furious".

I guess it can be pulled of, if you can adapt the motor to the motherboard control or something.

Has it been accomplished?

[DaveW]

Not too difficult-simply hook it up to a molex and a large capacitor. When the case starts up, the molex charges the capacitor and opens the case. When the power is cut, then the lack of power triggers a transistor, which uses capacitor power to close the case. Not too difficult to accomplish, but i can't remember which transistor to use, PNP or NPN...sure someone else can drop in. The difficult part is the mounting mechanism.

An old PSU would provide a capacitor with plenty of charge to close the door, but they can hold a lot of charge, and it could be dangerous, so don't go jumping in there :)

-Dave

[thechoozen]

hm....i´ve done a case with a motorized sidepanel (it open in suicide door style --> that means that the front part opens in an angle up to 90°, the back part of the side panel is attached to the case itselfs) but i cannot say anything about the electronics you need for the automation so that it opens when you touch the power button, i open it manual with a different button for both directions open and close....

thats an older picture of it (next evo version is already down...)....i only use a small servo to open and close it, like those in paintball hoppers or rc cars...

http://www.babetech.de/images/Formula.jpg

[Dr. Kamolly]

DaveW, can you attach a drawing, that also clarifies how transistors work, I haven't talked electricity since high school physics.

As for the mounting mechansim, very easy! Attach at the front end, that already where the standard metal side latches in a groove behind the plastic front, and any kind of hinges will do the trick.

My problem is finding a motor that can do the job, and SAFELY connecting it to the motherboard without frying the board or the motor, especially it will be new gear. Godwilling.

[xmastree]

I wouldn't go anywhere near the motherboard with it. Run it off the power supply directly. The only problem is making it close. There is power still available, but not much.

Depending on the type of door, you could use gravity or a spring to close it. Power on and the 12V is fed to a motor to wind the door open. When it's fully open it trips a microswitch, turning off the motor and energising an electromagnet (steady on Dave...) to hold it against whatever force is trying to close it.

Remove the power and it closes.

[DaveW]

Xmastree, it's a good idea, but isn't it a little...overcomplicated?

The type of circuit...hold on, i'll see if i can simulate it with some software.

-Dave

[DaveW]

Actually Xmastree's idea is probably the easiest. Although my idea works, it involved a bit more than i anticipated: there were a few things i'd forgotten about.

-Dave

[Dr. Kamolly]

I like xmastree's idea, the power can be obtained from the molex supposed to go into the floppy disk drive, I don't need it. But what does this microswitch look like? What triggers it? I mean mechanically?? Electronically?? And the axis of the door would be vertical, from side to side.

I was thinking something like the motor of an air conditioning unit's splitter or whatever it's called, it just goes left to right or upwards downwards and vice versa. This motor already makes the splitter shut the outlet of the ACU when you turn it off. If the continous up/down movement is shut, maybe it can work. Just shooting in the dark!

[xmastree]

The microswitch (http://feh.eng.ohio-state.edu/Design-Project/References/microswitch_wiring_diagram.gif) is like a mouse button switch, and would be activated mechanically when the door touches it.
http://en.wikipedia.org/wiki/Microswitch
http://images.google.com/images?q=microswitch
In the industry it's also known as a limit switch when used in this way.
Since they're usually changeover switches, it would be easy to divert the power from the motor to the electromagnet when the door is fully open.

The hard part (IMO) would me making the door close again smoothly.

I think something like a roller would be easiest. A door made from cloth, which would roll around a rotating vertical rod, and with the opposite edge running in guides to keep it straight.
As for the closing force, that's the tricky part. A spring would get harder to pull as it is stretched, slowing the door. IMO, gravity would be better.
Some fishing line or similar fastened to the top edge of the door, round a pulley and hanging down with a weight on the end so that as the door opens, the weight rises. To keep things straight, you might have to fasten some to the bottom edge too.
http://www.lotechdesigns.com/host/images/59slider.png

[DaveW]

Crimson's Doom3 had 2 different types of door on it, one using Servos, and one using and old CD drive motor. Both sweet as hell.

-Dave

[Dr. Kamolly]

I've seen CS's Doom3 mod, first of all, the man is a legend, all we need is a mini Marine and some ghosts swarming around the case!!

So, I came out with one question, what makes a CD tray motor change its mind and go backwards and forwards??

I'm sorry if anyone is bugged by all these questions, but I feel if I understand "how stuff works" then I can get a better design.

[DaveW]

Passing the electricity through it in the opposite direction makes it turn the other way. Not all motors can do this, but obviously the motor in your CD drive can.

-Dave

[Dr. Kamolly]

Yes I know that, I was wondering if there was anything inside the motor itself that changed the direction of the current?? You see, I saw the videos in CS's Doom3 mod, and saw the CD motors change directions, may be he used a switch or something. But how does it happen in a normal optical drive??

[xmastree]

The easy way to drive a DC motor in two directions is with an H bridge.

http://www.lotechdesigns.com/host/images/1553Hbridge.png

Turn on the transistors in diagonally opposed pairs.
So, top right + bottom left, current passes right to left.

So, top left + bottom right, current passes left to right.

Turn them all on and it blows up...

[OvRiDe]

Turn them all on and it blows up...

Doh!! Sounds like experience talking there!!! :)

[xmastree]

Sort of. I used to work with such circuits, but driving big stepper motors. Big, as in about 6" diameter and 12" long, running of a 60V supply. If the logic failed, then the wrong combination of transistors would turn on and let the smoke out.

[Mach]

You might want to also look at Mashie's Y2K bug mod. He's using model boat sail servos to open and close the wings of the bug on startup.

I'm currently doing a mod that has a door similar to the Doom 3 mod. I'm using a servo modded to be continuous with a servo tester attached to control the movement from a knob. http://www.robotlogic.com/product_servotester.html
I'll let you know what I find out as things progress.

xmastree is correct that you can burn up the motor if the motor is not stopped before reversing direction or something similar. Most sites that I've found recommend a series of relays to control the motors. I experimented with the phidgets servo kit for the control and will be using their USB knobs for other interfaces but the servo tester above was a more compact solution.

IIRC, the Doom 3 mod doesn't use microswitches. The motor opens with the switch and closes with another. In the off position, the door is stationary. This is the blast door btw.

[xmastree]

xmastree is correct that you can burn up the motor if the motor is not stopped before reversing direction or something similar.It's not the motor which burns. If you imagine all those transistors on at the same time (or any two on one side) there's basically a dead short between the suply rails. The fuse ought to blow, if there is one. If it's a fast enough one, it will blow before the transistors...

[Dr. Kamolly]

I'm electrically challenged, I must admit I understand fragments of what you say! To get started, what does a transistor do and how does it work?? And what makes 2 transistors work alternately?? Sorry if you're getting bored or anything.

[xmastree]

Think of them as switches.
Apply a small signal to the base (the middle connection) and it allows much higher current to flow between the other two.
Actually, they're more like throttle controls. If you know about engines this will mean more to you. However, in this application they should be either fully on (throttle open) or off (throttle closed). Nothing in between.

As for making them work alternately, that depends on the control circuitry.

The bases are the ones without conenctions on my drawing. To turn on the bottom ones, you need to push current into the base, by connecting it to a positive voltage with a resistor to control the current.
For the upper ones you need to pull current out of the base, by connecting it to a negative voltage via a resistor.

You could, in fact, connect them together with the resistor, so that each one becomes the other's source.