ComputingYou will see this often
Optical mouse
Also called USB mouse, wheel mouse.
The best source of small snap-action switches in the house, plus a quadrature wheel and a USB cable. The optical sensor is not a useful camera.
A donor is the dead machine. The parts below are what is still worth removing from it. “Leave it” is a part that is physically in there and should stay in there: too dangerous, too worn, or only useful as part of a repair you are not doing.
A scrapped machine is a box of parts that failed at different times. The reason it was thrown out is often one bad piece. The motor, the cord, the supply, and the screws are frequently still good. This index says which is which.
Why it is in the trash while the parts are not
The cable frayed at the strain relief, or the switches started to double-click. A frayed cable often means the switches are still good. Double-click means the switches are the part you do not keep.
Before you open it
Do this while it is still unplugged, cool, and not leaking. Nothing energetic. Pull the battery on a wireless one.
Where the dead machine usually is
- Home office — In the house
- Junk drawer and cable box — In the house
- Office cleanout — Commercial
A drawer of them accumulates. Sort by whether the click still feels sharp.
How it comes apart
Screws under the glide pads. Peel the pad carefully if you might reuse the shell.
Tools: Phillips 00, Iron if you are harvesting switches.
Words on this page
- quadrature
- Two signals slightly out of step, so a circuit can tell which way something is turning, not just that it moved.
What to take
The table is the short version. The notes under it describe that part inside this machine, not only the general description.
| Part | Call | How many | How often | Where to look |
|---|---|---|---|---|
| Microswitch | Prize | 2–5 | always | Under the main buttons and the side buttons. |
| Quadrature encoder | Worth pulling | 1 | usually | The wheel. |
| USB cable | Worth pulling | 1 | usually | Out the front. |
| Indicator LED | Bonus | 1 | usually | Optical illuminator. |
| Tactile switch | Bonus | 1 | sometimes | DPI button or battery door. |
Prize
Omron D2FC series or a clone. Logic current, not a motor switch.
Under the main buttons and the side buttons.
Desolder. Note the feel. Mushy ones are the reason the mouse was binned.
Sharp ones are excellent. Double-clicking ones are scrap.
Worth pulling
Mechanical quadrature, coarse.
The wheel.
Keep the wheel and the encoder as a unit.
Worn detents are common.
USB-A. The failure is usually the first 50 mm.
Out the front.
Cut off the frayed end and you still have a short cable, after you test it.
Test under flex.
Bonus
Often an IR or red LED aimed at the desk. Not a laser you can use.
Optical illuminator.
Leave it unless you want the LED.
Fine.
Small tact.
DPI button or battery door.
Desolder.
Good.