Introduction: Remote On/off Switch for Computer
I have a second computer which I access with SSH located about ten feet away. If the motherboard had wake on LAN I would use it but it doesn't and I am too lazy to get up out of my chair. With this remote switch I don't have to.
You will need:
- A piece of a perf-board that you can cut a small piece out of.
- Shield stacking headers for Arduino http://www.adafruit.com/products/85
- 4 x AA Battery Holder with On/Off Switch http://www.adafruit.com/products/830
- DC Barrel Jack Adapter - Male https://www.sparkfun.com/products/10287
- Adafruit Perma-Proto Quarter-sized PCB http://www.adafruit.com/products/1608
- Breadboard-friendly 2.1mm DC barrel jack http://www.adafruit.com/products/373
- IC Socket - 8-pin http://www.adafruit.com/products/2202
- 470 - 560 Ohm resistor
- Optoisolator https://www.sparkfun.com/products/314
- Keyfob Remote Control http://www.adafruit.com/products/1095
- RF receiver - 315MHz Momentary Type http://www.adafruit.com/products/1096
- Hookup wire (22 Gauge, red and black))
I wish it was possible to purchase all these parts from one supplier to save on shipping but that is not the case. Many of these parts are only available from one supplier.
Step 1: Front Panel Adapter for Inside the Computer
The first picture shows the front panel connectors that are standard on most newer motherboards and cases. If yours don't match the drawing you will have to make changes to fit your motherboard/case.
This piece breaks out the connectors for the power switch without interfering with the normal operation of any of the front panel controls.
Cut a small piece from the perf-board like the one in the second photograph.
Cut two pieces of the female stacking headers, one with 5 pins, and one with 4 pins. leave enough extra so you can sand the ends smooth.
Solder the 5 pin header into the five holes on the right in picture two. As the male pins point up.
Solder the 4 pin header into the middle holes, use the bottom 4 holes leaving the top one open.
Cut 2 pieces of the 22 guage hookup wire, 1red, 1black, long enough to reach out of the case to where you are going to want the receiver to sit.
Solder the red wire into the middle left hole, and the black wire into the next hole up.
Twist the wires together loosely.
Step 2: The Battery Box
Connect the wires from the battery box to the DC Barrel Jack Adapter.
You can use a plug in power supply, like this, instead of the battery pack if you want to.
Any 5-6 volt power source will work.
Step 3: A Word About the Optoisolator
The optoisolator is sometimes referred to as an optocoupler. The two names sound opposite but the optoisolator does both. It allows you to pass a signal from one device to another with no electrical connection. The small four pin IC contains an LED and a photo diode. When the LED is lit current is allowed to pass through the photo diode.
Step 4: The Receiver
The first part to solder is the 2.1mm barrel jack. Solder the barrel jack into holes A-2 , A-4, and hole number 3 in the ground rail.
Cut two pieces of the female stacking headers, one with 7 pins, and one with 2 pins. leave enough extra so you can sand the ends smooth.
Solder the headers like in the first photo.
The 8 pin IC socket is not shown in the illustration, it should be soldered into holes E11-14 and F11-14. The alignment notch should be pointing to the right.
Solder the resistor and the wires as shown in the illustration to finish the receiver.
Plug the optoisolator into the left side of the socket with the alignment dot pointing to the right.
Plug the radio receiver into the 7 pin header, like in the third photograph.
Step 5: Putting It All Together
Open your computer case and disconnect the wires to the front panel controls.
Plug the front panel adapter you made in step one into the front panel connector on your motherboard.
Plug the wires for the front panel controls into the adaptor. Follow the diagram in step one and watch the polarity when reconnecting the wires.
Run the black and red wires from the front panel adaptor out the back of the computer.
Connect the red wire to pin 4 of the optoisolator and black wire to pin 3.
Plug in the battery and press any button on the remote to turn on your computer.