I've had a lot of trouble designing a power button that worked consistently and looked half decent. There are plenty of switches you can purchase online that look ok, but I wanted to try and keep everything made "in house," using either wood or 3D printed parts.
A PC power switch is a "momentary" switch as opposed to the more familiar “toggle” switch. A momentary switch only completes a circuit for the brief time that the switch is pressed down and fully engaged. When the switch pops up the circuit is broken. The switch is attached to the motherboard and the motherboard starts the system when it detects that the switch has created a live circuit. If the switch were held down, and the live circuit existed for several seconds/minutes, the PC would most likely continue to reboot over and over. When the switch is engaged properly, that is pushed and released, the next time the circuit is detected the motherboard starts the power down sequence.
The momentary switch used in PC’s require that the switch be spring loaded and that the circuit is not “always on” like with a toggle switch. The presents some interesting design challenges.
These are all the parts that compose the power button assembly. The red base plate, the green spring-loaded button, the red electronic switch bracket, and finally the electronic switch itself. You can purchase these small electronic switches for around a $1 each.
The power button with spring is printed in PETG 3D filament. This filament is very strong and will bend without deforming. When the button is pressed down and released it will return to its natural position. This creates the spring effect. The switch is attached to the mounting plate via 2 recessed holes. A small amount of glue is placed into each hole to make sure everything stays in place.
The electronic switch bracket also attaches to the mounting plate via 2 recessed holes. This bracket holds the electronic switch in place and allows the spring button to “bottoming out” at a point where it won’t break. A small amount of glue is also placed into these mounting holes.
This is what the assembly looks like when it’s put together. When pressed, the green spring loaded button activates the electronic switch. When the button is released it returns to its natural position and disables the electronic switch.
The next photograph is the mounting plate installed in a case. Please note that the USB ports appear to be out of center. This is merely due to the angle that the photographs were taken.
I'm happy with how this part came out. It's unlikely to be redesigned for a while due since it took multiple designs to even reach this point. This switch will be going into all our Wooden PC's. If you are interested in tracking the progress of our Wooden PC cases, just click the follow button on the right.
Status - On Kickstarter!
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