Electronic Automated Hidden Stash Built Into Table (easy and Dirt Cheap)

Intro: Electronic Automated Hidden Stash Built Into Table (easy and Dirt Cheap)

Hi guys! So I was playing deus ex 1 and 3 and all the hidden stashes behind the TVs and pictures and under floors gave me an idea! I'll make myself something similar-how about a place to store my pens that slides up from my desk on press of a single button? So... Yeah, so I made it. I gotta admit that this was more like a fun project though; it didn't really take me much time to complete and quite frankly, I could have done better with specialized tools and will to let budget get over 1 buck (really). Therefore, I will do my best describing how I did that, but please keep in mind that although I find the final product fully satisfactory, it could be better. So consider this an inspiration, rather then a tutorial on how to do it the best way. 

STEP 1: Materials

You will need:
        -An old CD drive. I got one for a buck or so. It doesn't have to be fancy as long as it is tray loaded, not slot loaded. (You can't use  the ones with hole you just put the CD straight into.)
        -some thick wire, and also some thin one
        -wood screws
        -plank (length=length of the table; width=10cm or so; height=1 cm or so)
        -cardboard, thick paper, rubber strap
        -poster clay
        -short metal straps, some more wood-we'll use it to mount the plank to the current desk
        -normally off momentary push switches (I got mine from a VERY old keyboard)
        -2x2AA batteries holder or 1x4AA batteries holder (not recommended, but exactly what I used).
Tools:
Screwdriver
combination pliers
needle
scissors
drill (optional, but recommended)

STEP 2: Disassembling the CD Drive

Take the CD drive apart. Just remove the case, the laser, 2 motors and stuff like that. In fact, you don't really need to disassemble that far. I did that because I'll use the other parts. But anyway, it is necessary to get to the wires of the round motor, as seen on images below.

STEP 3: Extending the Desktop

First off, cut the aforementioned plank in three pieces. One will go left to the drive, one right to the drive and one will be 14 cm wide and I guess you could put it on top of the drive, but I replaced it with some much more lightweight cardboard. Using some additional wood, metal straps and wood screws, we'll mount the pieces of plank to the desktop itself. With help of thick wire and even more screws I put into the bottom side of the desk, I can easily make the CD drive stay in place.

STEP 4: Making the Stash Itself

There is naturally not much free space between the table and the drive itself, but I figured out the gap is big enough for me to be able to put some pens there. So I made myself a paper holder for them. Using needle, I poke some holes evenly in a thick paper, then I pulled a rubber strap through them. I just made a knot on the other side of the paper to make sure the band doesn't come loose. I bent the very end of the paper 90 degrees and glued it to the tray using a poster clay. Yeah, I know. But it works. Just some wise words here: to make sure the paper doesn't stick anywhere during the opening/closing process of the tray, you want it to be LONGER than the drive itself, so that it slides on the rear end of the drive. This way it'll stay away from the variously shaped guts of it and it won't stuck that easily. (At least that's my experience talking; you may came across some differently shaped drive where you won't run into this problem.) 

STEP 5: Door

I placed the door on axis so that they open automatically once the drive slides up.The axis is made from a thick uninsulated wire that is secured with 2 wood screws that I put into the plank from bottom side. The door itself rotates freely along this wire with help of thin wire hanging loops, as seen on image. To prevent the door from being stuck every time the tray elevates, I had to "chew out" the middle part of it, but maybe you won't need to do that.

STEP 6: Circuit

Generally speaking, there are 2 approaches to making the motor go both ways, when I don't count some fancy H-bridge or voltage-sinking-using electronic circuits.
        1) Re-purpose a line car remote control.
        2) Resemble the schematics on attached image like I did.

If you have a single 4 AA battery holder, just solder the middle wire in middle. The motor is the motor of the CD drive. You can easily connect it with the rest of the circuit just by plugging wires directly into the motor connector. I did the same thing, securing it with poster clay. 

Remember: Whether you go for the first or second way of doing things, never press both buttons at the same time, as that would lead to a short circuit. 

STEP 7: Fine Polishing

I did none. But I might use some wallpaper along with some fancy metal stripes evenly distributed across the plank to mask the door... That's it for this tutorial, hope you enjoyed it!

Comments

[mdsuave13]

i like the idea.. before i even looked at your guide, i watched the video and immediately knew how you accomplished your task at hand.. Very good idea sir!

[thegoodhen]

Haha, thank you very much!

[SherylinRM]

Just curious. But if it is on your desk then why not

One: just use a molex from your computer to power it. and

Two: why not just use the button on the front of the cassette [dvd] player to open and close the unit?

Just extend the wires until they reach to where you want them?

I am sure there is a logical reason for the way you did it.

I am just not smart enough to figure out what it is is all.

Thanks for replying :)

[thegoodhen]

Hello, sorry about the late reply! Although I have 12 computers at home, I don't have any in the room this contraption is in. Also, there is no power coming from the Molex cable when the computer is off (Although there is some powering the motherboard, I think it's the purple wire coming from the power supply). In order to power the thing from a PC, I would need said PC to be running all the time, which is not practical (is that what you meant?). In case you meant providing the power over the connector from a different power supply, that could be done. But for that to work, I'd need to rule out using the batteries, as the idle current draw of a CD drive is probably around milliamps or tens of those, which would drain my batteries overnight. Also, it would be much more difficult to ensure the tray can go up and down. I'd have to either use 2 power supplies (which is just silly :D) or some sort of special switch (maybe get one from a line car toy) or use additional electronics, such as L293D H-bridge. Power bricks that plug in wall increase the bill (albeit not significantly) and they sometimes tend to emit high pitch sound, and I use that room as my bedroom, which is another reason why decided to stick with this design.

[SherylinRM]

Actually yes I was thinking of using a second power supply.

Examples can be found here. there are literally hundreds of choices for it.

my favorite version of this is this one.

Anyhow, hope this helps you understand my question better.

Thanks again for your project :)

[thegoodhen]

Again, super sorry about the late reply, It'll get better, promise. Well, sure. You could just use a Molex connector from a bench power supply/old pc power supply. From the top of my head I am not sure if you'd need just 5V or both 5V and 12V supplies. So, one way to approach this would be to get an old PC power supply, loading it down using a high power resistor (otherwise it might not even start up) and then using the molex output by plugging it into the drive with the original electronics still in there. This is a bit of an overkill though, since it involves power source orders of magnitude more powerful than you need, which furthermore might not be designed to be running 24/7.

You could use a different power supply, but then I'm not sure if you need to use both 5V and 12V rails for the drive to operate correctly. If that's the case, you'd need 2 power bricks (wallwarts).

Alternatively, you could use just one power brick, microcontroller and an H-bridge, but that would complicate the whole stuff...

This being said, I could make a kit with like a numpad and everything. :D If you put in the correct code, it opens up. That would be kinda cool. If I get some time, I'll take a look into it.

Does that answer your question?

[SherylinRM]

It is a dvd drive so just one molex would be sufficient.

As for running 24/7. Many people leave their computers on 24/7 all the time.

however any cheap old PSU [power supply unit] with suffice.

You just have to short out the green and one of the blacks for "power on test" to work.

Also have a constant load so as not to blow the PSU. A small light bulb is sufficient.

Ok I guess I am done.

Thanks for your replies.

And try out the links I suggested :)

hope this helps :)

[thegoodhen]

Yes, I... I know that. I have a pc power supply modded to work as a lab one as well as many old pc power supplies in my box. Sorry, I am just not sure where you're getting at :)

I thought you were asking a question, but now it seems like you were trying to inform me about the hackability of a PC power supply... Sorry, I am just really confused now.

[SherylinRM]

No problem. Sorry I confused you.

Have a nice day :)

[thegoodhen]

No problem! You too! If I can be of any help, let me know! :3

[HuzaifaT1]

Amazing! I'm definitely going to make it. just waiting for wires and battery holder to arrive.

I just want to ask.. would it possible to add some LEDs (red and green) which would turn on when I press the buttons?

[thegoodhen]

Hello, sorry about the late reply. Yes, you can do that. Just wire them in parallel with the motor. Connect them so that the positive lead of one is connected to the negative lead of the other and vice versa and then connect the whole thing to the positive and negative leads of the motor and you're good to go.

I don't think you need any sort of resistor, since the dropout voltage of the green LED is right about the 3 volts. For the red led, it's gonna be a bit brighter than the green, I suppose, but it shouldn't get blown.

The only risk is when you only put one diode there. You risk a destructive reverse breakdown from the back emf.

Basically, the motor is going to kick back as the electromagnetic field collapses, which might shorten the life of the LED. But with 2 leds wired like I mentioned... Well, it's not the best engineering practice, but it's gonna work just fine.

[HuzaifaT1]

i think it will be better to solder the wires together rather than using poster clay and then insulate it with some duct tape, this would make the connection much more durable.

if I use LED Diodes to light up Green and Red when the buttons are pressed, would it be necessary to use resistors, as sometimes they may be damaged by a too high voltage, the fear is that their may not be enough voltage to charge the motor.

I am open to any elaborations

[bennyj121]

You could use 2 spdt relays and 2 momentary switches or a dpdt toggle switch to move the drive (or any simple dc motor) both directions. Here are quick sketches of how that would be wired.

[mrandle]

Would the motor be strong enough to mount a piece of wood that matches to the top. That way you don't need the flap.

[thegoodhen]

Sure. It can push up a LOT. The problem would be it would probably close once you cut off the power supply... Also, you would probably really need toy stay away from CD-ROM drives that use rubberbands in their mechanism.

[PetrichorXFi]

I would guess that you could use really thin wood, or perhaps a sheet of that "fake wood lamination" stuff.

Probably would not work with wood the thickness of the desk though

[mrandle]

That's probably true, you have to factor in what you are holding up as well. You could plane the wood down possibly so that it looks the exact same as the surrounding desk and also be light weight!

[sherenon]

I have used the cd rom assembly hack for other projects before, it should hold a little more than half inch ply wood .

[hatpaw]

What about keeping the drive's button circuitry intact? As it is, a second press will retract the tray and close the door. You should be able to extend the button to a better location