Cool Ways to Repurpose Old Computer Parts




Introduction: Cool Ways to Repurpose Old Computer Parts

About: I mostly do electronics, PCBs and simillar, but I also like metalworking, woodworking, fixing things and all sort of cool and stupid things :)

In this instructable I will briefly give you some ideas on how to reuse some parts of old computers that everyone is throwing away.

You will not believe, but these old computers have many interesting parts inside.

This instructable will not give full instructions on all the project,because it will get too long. But it will give you many new ideas on how to use these old components you will find inside. Maybe I will cover some of the projects later in following instructables. Post in the comments what do you want to see in detail.

Here you will see some of my past projects I made with these recycled parts. some of them are "mainstream", others are not so much :)

Step 1: Convert the ATX Power Supply to Benchtop Power Supply

This is the first project I made, many years ago, when I was still in middle school.

The project is very easy to do. Just chop off the connector and identify the wires:

- black wires are ground (negative)

- red wires are +5V

- orange are +3.3V

- yellow are +12V

- blue is -12V (comes handy in rare cases)

Connect the above wires to some connectors or therminals, so it will be easy to connect your project boards to them. I put just ordinary screws on some plastic board, because back then I had no money to buy banana plugs.

- green wire is important. It needs to be connected to ground - black wire in order for the power supply to turn on

- purple wire is +5V standby power. If you connect the LED on it, it will turn on if the power supply is plugged into mains. You don't need to connect it if you do not need it.

- grey wire is +5V POWER-OK. Connect a LED here if you want to see when the power is OK. If you overload the power supply, the LED will turn off and you will know that there is no sufficient power.

Most of these ATX supplies need to have some load present on +5V(red wire) if you want to get the full power out on +12V line (yellow wire). So if you want to extract the full power out, you need to draw an amp or two from +5V, so just put a few power resistors (10 ohm or so) or some 12V car headlight bulbs on the +5V line and you are good to go.

It is good to leave one or two 4 pin HDD power connectors hanging out. You will see later that they come in handy.

Step 2: HDD Mini Grinder

Now that you have a power supply, you can put it to some good use.

Take an old HDD and plug it to the power supply you made earlier directly to the HDD connector you left hanging (I told you it is going to be useful). You want the HDD to start spinning. If it does not start spinning, try to switch a jumper on the rear side in order to spin when the power is applied. Just try all the combinations, one should work.

Then, disassemble the HDD drive.

In the guts you will see the plate, arm and two metal things that are magnets that move the arm. You can rip the arm off because you will not need it, or you can just leave it in.

You can take the magnets out. They are very strong and can be used for many cool things. Watch your fingers!

Then unscrew the plate off the motor and glue some fine sanding paper on it. Cut it to shape and assemble it back on the motor. Now you have a mini grinder. I made a slight modification and added more plates from many drives on the same shaft, so the grinding plate is heavier and has more inertia.

The older the HDD, the better it is, because it usually has stronger motor inside.

Step 3: Convert Old CD-ROM Into Music CD Player

If you have one of that older CD-ROM drives that have headphone jack, then you have some cool old junk :)

These players can play regular audio CDs all by themselves!

Just plug them into your converted ATX power supply, or create separate power supply that supplies 5V and 12V and you are good to go.

Just insert the CD, plug the headphones in the jack (or connect it to an external amplifier via this jack) and press the play button. Voila! Music plays! You can ajdust the volume with built in potentiometer and you can also skip tracks with play button.

Step 4: Convert CD-ROM Drive Into Headphone Amplifier

This was some quick fix project I did in middle school.

I needed to make a headphone amplifier for a TV that had only LINE OUT audio output in the rear. The "line out" output does not have enough power to supply the headphones with enough volume for normal listening, so I needed an headphone amplifier. Fast.

I opened one of this old CD-ROM drives I had laying around. Don't be affraid to void some warranty :)

I assumed, that if it has headphone output, it should have headphone amplifier inside. I was right.

Then you open the thing, you will often see 2 separate circuit boards. One big, and one small, near the front face.

This smaller one is the right one.

Just start googling the IC markings and one of them is bound to be an headphone audio amplifier.

In my case it was MS6308 in one device and BH3540 in the other. They are all pretty simillar.

Open the datasheet and see which pins are inputs and which are outputs and which are power pins and what supply voltage is recommended. Follow the traces on the PCB to see where are they connected. Then you can break those traces and solder your wires to them. Inputs and power often go to the connector that goes to the main board. Unsolder the cable and there is a good place for you to solder your wires. Output is of course on the headphone connector.

You basically need to supply the power(often 5V) and left and right channel signal wires and signal ground.

I also had the option to shorten the PCB since I figured out that it has the part of PCB where none of my connections go. Although this step is not necessary an could be risky.

I also made a small 5V voltage regulator board, so I could power the board with wall adapter which had 9V output. but you can avoid this step by using 5V cellphone charger.

Then I quickly put the boards in some old plastic box I had laying around. I just hot glued everything togheter, since it was just a prototype and needed not to be pretty.

Now, about 10 years later, the amplifier still works :) Still hotglued though.. :)

Step 5: Use Computer Case for Something Else

I re-used my case by installing my CNC router electronics inside the case. Including the inverter for the spindle. Everything fitted nicely inside.

These cases are great for some bigger projects. I have seen people use them as bird houses, post boxes, you name it.

Step 6: Do Something Cool With Old Printer Parts

The printers have all sort of cool parts inside. Guide rails, motors, gears.. you name it.

I converted one of those old inkjet printers into the Most Useless Machine - Advanced Edition :)

I stripped the printer of all of the plastics and left only the base, the guide rail, the print head carrier, the motor that drives the head and the optical encoder for positioning the head.

I figured out how to read the incremental optical encoder and drive the motor with Arduino motor shield, added a servo motor on the print head carrier for moving the arm and in few stormy weekends, and the useless machine emerged!

See it in action in the video above!

This project is too big for just one instructable step. I will probably need to make a separate instructable on this one.

Step 7: Save Some of the Components for Later

Save the fans, heatsinks, LEDs, switches and simillar stuff for later to use on different occasions.

Old CPU heatsinks are ideal for cooling powerful LEDs, power supplies have many smaller heatsinks that you can use for voltage regulators, also the wires come in handy



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    23 Discussions


    3 months ago

    "Big f**** aplause!!!!" Amazing ideas, and the last one made me laugh for some time... Can´t stop watching.. Thanks for sharing.

    1 reply

    Thanks to you too ! :)

    Will the CD player play MP3s? I have 2-3 old PCs broke down and was looking for projects for them. Power supply and CD player look good. (I already took one of the CD drives apart for the little drive motor to replace a bad one in a BluRay player I have.)

    2 more answers

    Congrats on your repair!
    Sadly the CD player will only play regular audio CDs which have 20 or so tracks in WAV format. WAV format is just a recorded raw sound waveform, like the grooves on the vinyl record. The reader just reads the waveform and plays it directly. MP3 format is encoded, and you need some digital processing done in order to play it. I don't believe there is an easy way for converting this players to play mp3.

    No, the decoding algorythm isn't implemented in readers.

    Love the useless machine. Have you had tome to creat another Instructable around it?

    1 more answer

    Yes I will. Its on the to-do list now.

    Awesome useless machine from useless parts. :)
    Most desktop PCs are thrown because they are outdated and too slow for newer OS and programs. So a few are thrown in working conditions which can be used for LinuxCNC.
    Your CNC router looks pretty rad. Can you tell me which one is it? And do you have 2 controllers because although one is visible in the front panel, another one is stowed in the ATX Power compartment? Also what are the 100 or so white terminal blocks at the bottom of the enclosure for?

    1 reply

    In the ATX power compartment there is a power inverter for the 800W water cooled chinese spindle motor. The controller is from PlanetCNC, model MK3/4. The router was a design project made by members from the association of electronics engineers and hobbyists in our country. We made kits for around 100 of these machines a few years back. I believe parts are not available any more.
    Terminal blocks are there for the distribution of all the cables that go in the machine. 4 wires per stepper motor, 4 wires for spindle, 2 per axis limiting switch... I connected all those wires on terminal blocks. and from there they are spread to the electronics. The terminal blocks were a way for me to save couple of bucks for the connectors, since I don't need them, because my machine is always stationary, and I will need to disconnect the wires for transportation only in very rare occasions. Terminal block are still better than direct wiring to each component. In the need of disconnecting everything its much easier this way.

    Oh please please please please show us how to make the advanced most useless machine ever! It is so funny!

    1 reply

    A lot of those old scanners and printers will work on Linux. Which is an obvious choice for your old PCs. My newest one is 4 years old.

    1 reply

    The cool thing about those old printers and scanners is that they will not break down. Ever. Those new printers last couple of years if you are lucky.
    I have I have 18 year old inkjet printer on my desk. Still working good enough for what I need.

    I used to do all kinds of reuse of refuse, til the town implemented a 'mandatory' E-waste recycling, and pretty much layed claim to ALL of the refuse disposed of for metals reclaiming. I still have 6 machines up & running that were discarded, with little to no major repairs needed, 2 converted ATX supplies (incidentally, there was also a -5V on some of the older Pre-Core-2 supplies), power connectors for breadboards from old 3.5" floppy drive power connectors, and a 'junk box' of parts for experimenting with Arduino, Raspberry Pi, Etc..

    1 reply

    On the printer box it would be funny if the red switch pusher looked like a finger... fun for kids (or scary).

    1 reply

    I tried to make it to look like a cat paw, but I couldn't make it to look good enough so I abandoned the idea :)

    I'd love to see a follow up instructable on how you got an arduino to control the printer's optical encoder!!

    1 reply

    I will try to make a full instructable on the useless machine.

    My cat Whisper would love the switch-box at the end. ALL cats love apparently autonomous machines like printers, ejection mechanisms like VHS and DVD ejects, even the toast popping up...thanks for your lateral thinking, Dr Bono