Introduction: How to Make a Fair DIY Computer Mouse

About: Plastic- and electro-waste recycling Johannstadt

Fair electronic products are very rare. NagerIT & Fairphone are almost the only ones who are concerned about good working conditions and sustainability along the entire supply chain of their products.

In this instructable you will see how to build the NagerIT mouse on your own. If you need a (fair) computer mouse (for you or someone else) it´s a great project to learn soldering, more about fair electronics and optional some 3D-printing stuff (If you you want to build the ergonomic concept design->see the last steps).

Of course you can also buy the mouse from NagerIT if you don't want to build it yourself ;).

For more information check out:


  1. The NagerIT soldering kit:
  2. A soldering station (temperature controlled, but a simple one is enough)
  3. A metal sponge (steel or better brass)
  4. 2 screw drivers (Torx 9 & Torx 10)
  5. A small side cutter (or a nail clipper ;))
  6. A table mat if you have to protect your desk
  7. Maybe a "third hand"
    • You can also use other things to stable/ fix the cicuit borad & parts. Simply lying on the table is often enough.
  8. (maybe more tin-solder from fairlötet)

Step 1: Safety

  1. Do not eat (especially fingerfood): Small particles of tin can be on your hands and are not so nice in your stomach.
  2. Do not inhale the solder fumes directly and ensure a good ventilation: In particular, the flux (contained in the tin solder) smokes. If you solder a lot (like 8h per day) you should use a solder fume extractor.
  3. Be careful with the heated soldering iron: Not only the soldering tip gets hot, but also the whole metal part after the handle. Up to 450 ° C does not go well with your skin or other objects (cable, tools, ...). So always use the holder when you are not soldering!
  4. Don't let the solder legs fly: After soldering a part, the soldering legs remain on the soldering side of the circuit board, which must be snapped off. Hold them so that they don't fly into your or anyone else's eyes.

Step 2: Soldering Tips

    • Soldering temperature: 120-140°C above melting temperature
      • Melting temperature "fairlötet"-tin (lead-free): 227°C --> Soldering temperature: 345°C-365°C
      • (Melting temperature leaded tin: 180°C-200°C --> Soldering temperature: 300°C-340°C)
    • Clean, oxide-free surface (if necessary, remove the oxide layer with an external flux)
    • The soldering tip must always be wetted with solder
    • Soldering time (contact time of the tip with the part leg or cable): Maximum 5 seconds! If the solder does not flow during this time, the settings (temperature, soldering tip) must be changed.
    • Smaller parts are easier to reach with finer soldering tip, but heat dissipation is also faster (cools faster, is more sensitive), so it´s better to use a normal-sized soldering tip as long as possible
    • Strip off excess tin in a metal sponge (less heat loss at the soldering tip than a wet soldering sponge -> more constant soldering tip temperature & better for the soldering tip). Use a metal sponge made of brass or cheap alternative: stainless steel sponge (may scratch the soldering tip a little faster)
    • Soldering circuit boards:
      • Note polarity(+/-,...) of the parts! (LED, Switches, Chip, ...)
      • Fix parts if necessary (clamp, base, ...)
      • Press the soldering iron against the copper pad (via) and the part leg at the same time
      • Hold for 2 to 5 seconds (maximum 5 seconds!)
      • Add solder to the area until an even melting bath has formed (see illustration). Not to bulgy.

    Step 3: Preparation

    • Arrange all parts and tools on the table (possibly on a table mat).
    • Heat the soldering iron (about 350 ° C (662 °F) for lead-free tin).
    • Test the solder settings with a cable or/and an old board (desolder & solder some parts)

    Step 4: Important Instructions

    • Follow the order of the instructions (first flat parts, then higher parts and finally sensitive parts)
    • Always make sure that the parts lie straight and down on the circuit board
    • Polarities! ->Orientation: LED, USB-cable, buttons, sensor (chip)
    • Check always if no soldering point touches the next one (no solder bridges!)
      • (Some solder points are close together!)
    • Always cut off the legs on the solder side after soldering
    • Search "common soldering problems" to see how to not solder ;)

    Step 5: Watch the Video & Animation

    • In this video you can see the construction in a fast run.
    • In the next steps you will find more detailed information about each step.
    • build-yours did also an animation for the assembly steps:

    Step 6: Solder the Jumpers

      • Bit by bit
      • Make sure that the jumpers lie straight and down on the circuit board
      • Insert the jumpers (until the end) into the corresponding holes on the part side (see pictures) and solder the leg with the via (solder pad) on the solder side
      • Cut off the legs on the solder side

      Step 7: Solder the 0,1μF-condensators

      • Just solder ;)

      Step 8: Solder the LED

      • Polarity! Long leg (+) left (top view)!
      • Solder one leg, check, then solder the second leg
      • After soldering, carefully bend the led forward

      Step 9: Solder the Switches

      • Solder one leg, check (maybe adjust a little bit), then solder the second (and third) leg

      Step 10: Solder the Two 10μF-condensator

      • One leg is longer, but easy, no polarity ;)
      • It is a bipolar electrolytic condensator, so the orientation doesn´t matter

      Step 11: Solder the Rotary Encoder

      • This part will record your scrolling :)
      • Start soldering with the middle leg, check (vertical!) and solder the other two legs
      • Check and solder the outer case legs

      Step 12: Solder the USB-cable

      • Start with the shielding cable (silver)
      • Solder black, green white red
      • Check if no soldering point touches the next one (no solder bridges!)

      Step 13: Solder the Chip (sensor)

      This part needs a bit more attention, but with the following hints everyone can do it;)

      • Sensitive component! Discharge the static charge on your body (for example on the bare metal of the radiator)
      • Polarity!: Pin1=dot -> top-left (see pictures!)
      • Only solder with as much temperature as necessary
      • Solder diagonally to better distribute the temperature (see pictures)

      Step 14: Insert the Lens

      • Position the side that directs the light to the table top to the LED

      Step 15: Insert the Scroll Wheel

      • Carefully insert the thin side into the encoder
      • Just push on the thick end, don't bend!

      Step 16: Insert the Circuit Board & the Cable Into the Base Plate

      • Just put the board in (If it doesn't fit, check if you've cut off all of the solder legs)
      • Make a small bow at the beginning so that the cables arrive relaxed at the soldering points;)
      • Lay the cable in the cable guide

      Step 17: First Test!

        • Plug the USB-cable into your (switched on;)) computer
        • Your mouse should automatically work on Linux, Windows & Mac :)
        • Is the LED on?
          • If not check the LED-Soldering (Step 8):
          • Good solder points at the LED?
          • Polarity correct? (Minus is where the LED has a flattening (Search: "polarity led"))
          • Good solder points at the cable?
        • Check the mouse movement
          • If not working, check the polarity and solder points of the chip (Step 13)
        • Check the key clicks
          • If not working:
            • Good solder points at the cable?
            • Polarity correct? (The small rectangle where you can click are above)
        • Check scrolling
          • If it doesn´t scroll well, check if the encoder fits correct (vertical!) (Step 11)
        • If nothing works:
          • Check the colors and solder points of the cables (Step 12)
          • Check the polarity and solder points of the chip (Step 13)
          • Check the solder pointes of the jumpers (Step 6)

        Step 18: Screw the Button Caps on the Upper Shell

        • Guide the tabs through the cutouts and position over the screw holes
        • Screw the 2 short T10-Torx screws in
          • Just tighten slightly! (and vertical ;))
          • Check whether the button caps can click, otherwise unscrew again and carefully bend the tab in the appropriate direction

        Step 19: Screw the Base Plate on the Upper Shell

        • Just tighten slightly! (and vertical ;))

        Step 20: Stick the Sliding Plates & the Sticker

        • Just stick them in the markings and FINITO :)
        • Is everythin working?
          • NO
            • If you can't click, unscrew the upper shell and button caps, carefully bend the caps and test again.
            • Problems other than in step 17 ("First Test!"): leave a comment ;)
            • Here is also a german repair instructions from NagerIT:
          • YES -> NICE! :)

        Step 21: Finish

        You have built a computer mouse yourself that is as fair as possible across the entire supply chain. Check out for more information. There you will find, among other things, the current overview of the supply chain:

        Have fun clicking :)

        PS: Post a picture of your mouse! (Click on "I made it" at the end)

        Step 22: 3D-print an Ergonomic Design

        Because I work so much on the computer (CAD design), I wanted to try out a more suitable design for me. The mouse has an angle of 25 ° (should be the most comfortable for the wrist) and fits directly onto the NAGER-IT-base plate. Use the .stl-file below to print out the ergonomic upper shell. I've been using the design at work for half a year now and I'm very satisfied :)

        Please use a recycled or sustainable filament (whether you print yourself or have it printed). There are already many suppliers of recycled / sustainable filaments, just search the internet ;)

        I chose the GreenTEC filament for my mouse (GreenTEC is made from a high-performance and heat-resistant renewable biodegradable biopolymer).

        After printing, depending on the print quality, you should sand / scrape the edges and narrow passages.

        Step 23: Screw the Upper Shell of the Ergonomic Design

        • As you can see you don't have to screw button caps ;)
        • Just tighten slightly! (and vertical ;))

        Step 24: Finish :)

        Step 25: Share Your Experience

        If you've built the mouse, feel free to share your experiences.
        What went well, what didn't. Feel free to post a picture of your mouse :)

        Have you tried the ergonomic design? How pleasant is the variant for you?

        Have fun clicking :)