Junkbot Safari: Motors, Gears, Capacitors and Gravy




This tutorial was designed mainly for a group named N-List at the CADRE Laboratory to help explain how to salvage and collect parts for our enthusiast robotics projects. Please if you have some information that would help me or questions please feel free to email me.

I have recently gotten a taste for electronics and despite the fact that I love to ramble around stores like HSC, I am amazed by the largess of the south bay in the way of cheap/free materials that often are abandoned and on the way into our waste stream.

insert a photo of part on my bench

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Step 1: A Few Words of Caution

A few words of caution before I start.

Dumpster diving is a risky activity. Be aware, wear appropriate personal clothing and protective equipment (gloves/boots/etc). Never put yourself in a dangerous situation. You should go with a friend in the case of a mishap there will be someone to help or call help.

Electronic components are hazardous material.

You should be cautious when handling materials such as capacitors, transformers, or anything that stores or builds voltage. These types of parts can kill you.

Many electronic components are toxic you should use due care when handling them and wash your hands, especially before eating, smoking, etc, etc.

Understanding and being able to identify components is very important. I use a bunch of resources but here are a few that I have found:


btw, most of these originally came from a simple google search for identifying electronic components

Step 2: Where to Look

The sites to find materials.

We are luckily to be next to a large and extensive engineering department that seems to be updating equipment all the time. I also look at other dumpsters all the time for potential finds. More often than not the case on old towers and desktop machines will be cracked and this will allow you to quickly see if there is anything that you might be shopping for in the waste.

Step 3: Tools of the Trade

You can do most everything that you need to do in the field with a couple of screwdrivers and a bag or box to cart off your goodies. I find that a a basic multi-tool with pliers, knife, screwdrivers, etc is really handy all the time. You might find it helpful to add some extras though:

-a set of different driver bits for a driver (phillips, blade, torx)
-a set of precision screwdriver
-sometimes I carry an electric Driver/Drill for quick extraction

Step 4: Know What You Looking For

So you should have a list with you that reminds you what you need for the project. For this project I am looking for 470 to 2200 uF Capacitors, 6 to 12 volt motors, and any extra components (i.e. the gravy) that come on these boards for my junk component box.

I know that many older PCs often have capacitors on the motherboard, as most do most PCB's (printed circuit boards). Then it is simply locating the code for the 'size' of capacitors on the side of the component. ( if you need to learn more about components and how to identify them see my links in Step 1!).

Additionally I know that floppy and CDR drives usually contain small motors at the right voltage range; yeah I looked inside one that's how I know.

list pic??

Step 5: Extraction

So the key here is that you are going to locate and remove the boards or drives that have parts that you can use. You will leave behind extraneous cases and parts that will make it awkward or cumbersome to move. The goal will be to remove just the part or board that the component sits ons.

As you can see on this PC the side panel has already been removed, I check the number of Farads on the side of the capacitors. I will take the mother board out if the components are the right size.

Disconnect the ribbon cables, remove screws holding it down. You can remove any cards in the PCI slots if they don't have anything of use for you.

This machine also has CD drive! Excellent! Remove the screws and ribbon cables and slide it out of the case and into your bag. Save any loose screws; you never know when you might need them and they don't take huge amount of room.

Next you will be a responsible citizen. You should put any loose parts into the PC case so that they can easily be picked up by recycler. I make sure the area is as clean or cleaner than when I arrived. Usually the owners of these areas know that folks like me are on salvage operations. A sure way to get them to lock down this valuable resource is to make a big mess of small parts for someone else to clean up. Please be kind to those who allow you access to this material.

pics of dissembly, screws, cleanup

Step 6: Further Extraction

It is time to retreat to your workshop. Here you will de-solder the parts from the board and crack the case of the CD or floppy drives.

Look closely at the board with Capacitors; after you remove them there might be other things you want for you parts box such as resistors, potentiometers, ferrite beads, inductors, etc, etc, remember this is gravy.

Crack the case of the CD/floppy. most of these will have various tab and slots or screws to remove. As you get the case open you will identify small round objects often with two wires coming off to attach to a board. On one side you should see a shaft and you should be able to spin it. Locate what is mounting the motor and remove it. Again if it is screws, save them! Snip the wires as far from the motor as You can. Now look at the drive. A CD drive is full of gravy: laser, gears, sprockets, belts, rails, etc.; part out what you want.

I like to keep some zipper type bags to collect bunches of material and I prefer the divided containers you can get from the hardware store to sort the different types of components. You will have to decide your own organizational scheme.

Step 7: Yee Haw! Parts!

Congratulations: you now have the parts for you robots/project.

Now that you have done that, it is time once again to be responsible, you should take anything that has hazardous material such as the PCB to the e-waste collection. The non-hazardous material like plastics an metal cases should be taken to the recycling as well but obvious don't have nearly the danger of PCB and components.

If you aren't will to do this, don't do this kind of salvage. You will be creating a much larger toxic waste problem for your neighborhood/world.

Thanks for reading. Please let me know your comments, suggestions, thoughts.

happy cracking the case,

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    78 Discussions


    9 years ago on Step 7

    Any idea on what to dissect to get bike-sized gears (meaning gears the size of ones in bikes, not gears the size of bikes :D)? I'm building a pedaled hexapod-type thing for halloween but have no more bikes to scavenge gears from :p

    2 replies

    Reply 9 years ago on Step 7

    i haven't worked on bike gears, but I have see the tool usually used to extract bearings from the center of pulleys/gears. is that what you are looking for? sounds like a very cool project.


    Reply 9 years ago on Step 7

    hmm, i don't really know what you mean by tool used to extract bearings... i don't know much about gears and stuff since i'm relatively new to this and most of my projects so far have been with legos... im going to bike shop tomorrow for gears though since my dad is friends with the owner and we can get free gears/frames and stuff so i dont really need any help with finding them anymore. and yeah im being a unicorn rider for halloween so im making a quadruped robot for the unicorn :D (yeah, im so cool ive been a fairy for the past 2 halloweens)

    i sware with god that i turned my psu-on and while it is on touched capacitors and nothing happened 235w psu (i was making hydrogen)


    10 years ago on Introduction

    What could i use the Cd drive laser for? I've found a use for everything else besides the laser?

    1 reply

    10 years ago on Introduction

    have you taken apart a printer? i found a film canister sized capacitor that still had a charge apparently(i, as a precaution, discharge all capacitors i find with a screwdriver) and it discharged at a high enough heat to actually almost solder the screwdriver to itself!

    5 replies

    I once took apart an old generator, possibly 3000watts if I remember correctly. The largest capacitor was about 2" in diameter and 4" tall. I discharged it with a screwdriver like you did, and I ended up with three parts of a screwdriver that had a 1/4" thick shaft. It had enough power to melt my screwdriver in a sceond! It also melted the handle a little bit.


    crap. i've seen bigger capacitors, though. they come as large as milk cartons, in my experience. fortunately, i've never been allowed within fifty feet of one.


    I know someone that works at this place (don't remember what they were or what they did) that he said had very large capacitors in some of the equipment. When I asked how big they were, his exact words were "Some of them stood about as tall as you do." That's a 6 foot tall capacitor! He said they were 4' in diameter and were upwards of 250lbs! Now that's a big capacitor! Also, why are you not allowed within 50 feet of yours?


    1) they're not mine, they're my friend's, and 2) he knows that i'd end up blowing something up. or setting it on fire. or electricuting it. in short: it's a VERY bad idea to let me near something with any amount of destructive force because i will use it efficiently


    Reply 10 years ago on Introduction

    Here in Ankara,we have this whole street that is FULL of electronics shops.But my dad usually doesn't have time to drive me there and it's like 30 mins away without the nasty traffic over there.


    Reply 10 years ago on Introduction

    same here but I have to get my mom to drive me so I don't get to go near as often as I would like


    11 years ago on Introduction

    Does anyone know what I can salvage relays from? I really need some, but I can't afford the quantity that I need, therefore, I must salvage. Please help me.

    3 replies

    Reply 11 years ago on Introduction

    it is a thingy that you can found in cars with compressed natural gas (GNC)