Old CD drives are a decent source for parts to make things from. Since the computer industry has encouraged manufacturing churn for so many decades, it is pretty easy to find at least a few surplus drives to dissect. Inside these dusty relics, you will be lucky to find DC motors, switches, gears, springs and more. The tools you will need are pretty easy to come by as well. From the parts you will find, you can make a number of interesting projects.
You can get drives from old computers, which always seem to be at the dump, on the sidewalk of some neighborhoods, out on the loading dock of the school, in basements and garages, etc. It is important that wherever you get them they come to you legitimately free of expectations. These will not be functioning drives after a few minutes of the project. Teach your family to solder! Take a few pictures tagged as “MAKEcation” and put them in the MAKE Flickr pool by September 9th to enter to win a $100 Maker Shed gift certifiate!
Supplies: Old computer CD drives (older ones often have better parts) Plastic bags for storing parts (zippered half size sandwich bags are great) Small cardboard boxes for storing the larger metal and plastic parts Battery holder Tape Paper and pen Digital camera Paper clip
Tools: Safety glasses Small phillips head screwdriver Straight screwdriver Jeweler’s screwdrivers Pliers, needle nose or channel lock Utility knife Soldering iron Wire cutters/strippers
Concepts: How does it work? How is it made? Differences in technique and age of manufacture Identifying electrical components Getting and organizing supplies for future use
Time frame: An hour or more is ideal
Mastery Objective: Students and participants will know how to safely disassemble a CD drive or similar electrojunk for parts and project supplies so that they can name the parts inside the device, compare the varieties of manufacturing techniques to solve the same problem and organize the usable parts and components for future use in projects.
Process: What do you have? Probably the first thing to do is look at the exterior of the drives you have. Make note of any markings on the drive. Some things you will likely find are the manufacturer, model number, read/write speed of the drive and my favorite: Date of Manufacture. The date of manufacture will give you some context to judge the drives in your collection by. Often the older the drive is, the more “off the shelf” the components are.
Use your camera: Take some photos with your camera or camera phone to show the process of taking the drive apart. You can also have participants and students take pictures of each of the systems they find, and each of the types of components they find inside.
Case disassembly: Put on your safety glasses. Use a screwdriver to take the metal case off the drive. It will usually be 4 phillips screws on the sides that hold it together. In taking off the metal case, try to keep it from getting deformed. The steel can be useful later. You may find that there are plastic tabs holding one of the pieces in place. Try to get the case to just fall apart without having to be forced. Most of the time it will just come apart after you remove the screws and press on the plastic tabs. If you do have to tug on the parts, you may have missed a screw under a sticker. If all else fails, make sure all of the eyes are protected, and pull it apart carefully, probably below the table. Pop open the CD drawer by straightening out a paper clip and slipping it into the hole on the front panel. The drawer should open easily. You might even find a disc inside. To remove the drawer, you may have to pry apart the plastic sides, or it might just come apart easily. Different models have varying designs. Be careful if you put force on it that the parts don’t fly and hurt somebody.
Be careful not to Over-Disassemble! You may find that there is a dc motor that is in a plastic housing that holds it in contact with a gear which could serve as a nice little drive wheel. Take it out, but secure it together so it can be used in a future project. If it doesn’t stay together with screws or pressure fitting plastic, run a bit of tape around it to hold it. You may also find that the CD reading eye moves nicely on its’ slides. If it is controlled by a DC motor, this could be a neat system to use later. Basically, look at the things you are taking apart, and see if they can be used as systems or components. Securing the wires coming from the motor with a bit of tape will help keep them from breaking off later.
Motors and how to read them: You should find two types of motors inside: DC motor and Stepper motor.
The easiest way to identify a DC motor is by looking at the number of wires coming off it. Most have just two wires. DC motors are controlled by sending electricity through the motor, causing it to turn either clockwise or counterclockwise. Sometimes you may find that there are several more wires going into another area of the case. These can be to an encoder that helps read the speed and direction of the motor.
Stepper motors have more wires coming from them, and often are built right onto a circuit board. These turn by receiving a series of pulses, each of which advances the motor one step. By controlling the timing and quantity of the pulses with a microcontroller, it is possible to precisely set the speed and even the number of degrees the motor will turn.
Save the good bits As you go, put the useful parts into plastic bags or bins. Label the bags with scraps of paper for easy identification. You should be able to find at least the following:
- DC motors, usually one will open the tray, sometimes you will find a second to move the eye.
- Gears to drive the mechanisms
- Switches, either momentary pushbutton or other mechanical contactors
- Headphone jack
Desolder the components you want from the circuit boards: The headphone jack, LED, momentary switches and sometimes motors will be soldered directly to the circuit boards. You can use a desoldering braid and an iron to free these items from the boards. If they have fittings, you may want to keep the fittings and instead remove the headers that connect them to the board. You should be able to scrape the coating off the metal traces to solder the fittings to a wire for future projects.
Extensions: Make a vibrobot. Practice soldering and desoldering with the components on the boards. Use a battery holder to power some of the things you find inside. Use a fishing tackle box to store your parts in labeled bins. Make a video explaining what you have found inside your CD drives. Make a poster identifying each of the parts of a CD drive and telling what each does. Use the parts of the drives to make something amazing!
So give it a shot! You can try this solo, but it is definitely more fun scavenging old drives in a group with the stuff all ending up on the table. You can compare the differences and similarities between drives better in a group, and you can share observations about the systems. Having a nice collection of stuff to pick from is a great feature of the project. An added bonus is finding handwritten markings made by the people who made the drive. Give yourself and the group some time to explore what you find. In my experience, it takes a few hours to dig through the drives and then make something from the debris. You can do it in one workshop, or you can spread it over a few classes. Share your findings in the comments, and add your photos to the MAKE Flickr pool.