The Raspberry Pi is a wonderful little single board computer that is based on the arm architecture. You can use it for everything from a media streamer, as a server, and all kinds of computer applications. It has one shortcoming at least for now that is a small challenge. It does not use a standard power supply input. You can dissect a walwart and make a special adapter. What I would like to do is to make a generic interface that can be reused if the walwart ever goes bad.
Notice: This instructable requires knowledge of electricity and the ability to solder. We are not responsible for any and or all issues. Do this at your own risk to any life and or equipment. Get a professional to help even if you are the least bit unsure.Do not solderor touch anthing while connect5ed to power supply.
Step 1: What Is Needed:
Power adapter via a barrel connector that outputs 5 volts DC with enough current as your Raspberry Pi requires.. (I used the one from my Nslu2 ( 2 amp output) for testing. (Do not use any other boltage (i.e. 12 volts) or you will damage your equipment.
Micro (not mini) usb cable.
Female power plug that will hold the male end of the power supply
We will use the packaging for the female power plug as a temporary case.
Step 2: Dissecting.
You will want to separate the usb cable while not connected to anything. Do not discard the non-microusb end as you may need to use it to check which wires are which.
Once you have cut the cable, strip back the main outer covering.
Strip the red and the black wire so they can be soldered to the barrel connector.
If you do not have the standard color coding, you will have to test the cable manually. Be carefully not to touch any bare wires while doing this, as you could be electrocuted. If you are unsure, get a professional to help.
Step 3: Solder It.
Assuming you know how to solder... If not get a professional to help.
Solder the +5 wire (maybe red) to the tab that goes to the inner tube.
Solder the ground wire (maybe black) to the tab for the outer tube.
Step 4: Wrap It Up.
You can use electrical tape to wrap it up, Using some kind of small container is best. I just used the plastic cover from the package it came in for something quick, I will probably make something nicer later.
Step 5: Bonus: Gpio Adapter.
You can use an old "AT" RS232 to motherboard adapter cable for the Raspberry pi. You may want to cut off the RS232 db25 end so you can tine the wire ends to use in some other adapter board. Actually I needed the DB25 end for a PC project, So, I killed two birds with one stone. One less thing in the storage box.
Note: Looks better than using a disk drive cable.
Step 6: Another Suggested Implementation.
As one other instruble member said you could also use a external hard druve power adapter to also do the same thing. With this setup, you can still use the 12 volt line to power something else. (another rpi with a 5 volt regulator for instance).
Step 7: Use an Old AT (NOT Atx) Power Supply.
Do this at your own risk. We will not be responcible for any or all issues. Chances of electrocution causing death can occur. Get a professional to help before you start this project if you are even the least bit unsure.Be sure to cover any exposed live lines to insure there is no electrocution risk.
Wanted to make a Raspberry Pi where I could have several units in one case. Putting several power supplies in one box seemed like a mess. Instead I decided to use an old "AT" (not atx) power supply. I did not want to cut up the cable from the power supply. I looked for a dead motherboard in the junk box. There was onthe picrure attached:e! Now, had to get out the old heat fun (used for paint removal. Most "AT" motherboards are attached to the pc like
But if you have a dead motherboard it will not need the Power supply header anymore. So the mother board looked like the picrure attached:
Now we want to add heat to the back side of the motherboard to release the header. Be careful as it is HOT. Solder could come flying and burn you. Wear protective clothing. Then once the header is free and cooled, it should look like
the picrure attached:
Ahh, free parts!! So now I can use the header with the Raspberrty Pi once I have soldered some wires to the header. PC Power supply must be turned off and disconnected from wall power while soldering. I.e solder the header disconnected from anything. Hint: Be sure to also use a glue gun to seal the solder connections so nothing can get shorted out.
You will need a pinout listing for that particular power supply you want to use. (Varying power supplies are not all the same when it comes to the pinouts!!)
This power supply only uses two of the three connectors. But what we need is a +5v (usually red) and a ground (usually black) to power the Raspberry Pi. So we could eventually power up to four units. The disk drive cables could aso be used, but we let them be for drives we could attach to the Raspberry Pi.
Step 8: Potential Power Supply Idea.
Warning: Try this at your own risk. I will not be responsible for any or all issues.
Came up with a possible idea for a power supply using a 12v battery so that the Rpi is semi-portable. I also planned on using an NTE931 not the 7805T as the voltage regulator. Still need to add a switch and a fuse to the circuit, so you may see an update eventually. I am not an electrical engineer or anything remotely resembling one. This is what I came up with that might work, but it is definitely untested. Get a professional to help you with this. As I said try at your own risk. If someone has a better circuit please let me know.
Step 9: Yet Another Ps.
While going through my old files, I found this picture, but never tried it though