Today, I'll teach you how to hack a camcorder viewfinder! (Here I have my viewfinder next to a Raspberry Pi)
This is a basic I/O testing screen. You can use it for anything that puts out a composite video signal, like a Raspberry Pi (For an awesome wearable!) Video game console, VCR/DvD/Gaming console tester. It is made entirely from an old junked out camcorder I found in a trash bin, and it works great! The
entire project was 100% FREE! I used the tools any electronic geek should have.
Step 1: Parts Needed: Supplys
These are the supplys you will need for this project.
1: You need an RCA male to female-female splitter. This can be bought at RadioShack or on the Internet.
2: Electrical tape, any brand will do.
3: An RCA cable that you don't mind cutting up.
4: The camcorder you wish to hack apart. (This camcorder must have a viewfinder that uses a CRT display. LCD displays will not work. This display will be about 2/4 of an inch wide and a sure way to tell if it is a CRT is to look at the screen. If the screen is a bright Grey when off, you have a CRT display.)
Step 2: Parts Needed: Tools
For tools you will need the following.
1: A screw driver to take apart the camera and display.
2: A digital multimeter. (This is very important if you wish to correctly determine what the continuity and voltage required by the viewfinder.)
3: A soldering iron. This is used to attach the wires to the correct circuit's. (This is optional. I simply twisted the wires together and covered them with tape.)
4: A wire stripper. You can also use a knife, but be careful when cutting.
5: A bench power supply. (I made mine from an old ATX computer power supply) This is a must have!
Step 3: Safety Precautions
Before you begin, you have to take some safety measures. Enter safety gloves! These gloves will need to be made of a thick rubber that electrical charges can't jump through too easily.
These CRT viewfinders can carry some pretty high voltages. If you come in contact with these voltages, you would wish that you wore the gloves. DO IT! Now if you're the kind to follow the safety precautions in your flashlight manual, you will also want to wear safety glasses in case your flashlight... er, viewfinder spontaneously explodes and blows hot lava and Pop Rocks all over your face costing you millions of dollars in Hospital bills and Lawyer's fees.
But really, take some safety measures when dealing with these viewfinders.
Step 4: Get Crackin'!
First, take your camcorder and locate the viewfinder. This is pretty easy, considering that you had to find it when purchasing the camera. Now look to see if the viewfinder is connected to the camera via a cable or, if you don't see any wires, then the viewfinder is probably connected through internal wires. Take the camera apart, screw by screw until you can pull off the viewfinder. Also, make sure that you unplug the cable going to the camera or, if you get to deal with the internal wires, just cut them off and give yourself a little work room with them.
If you have the viewfinder off, you may dispose of the camera body and housing. Once that's done, go ahead and take off the viewfinder case. Keep the plastic case apparatus and lenses, you will need to put it back together when you are done.
Step 5: Realase the Probe!
When you have the case off of your viewfinder, you should see a small circuit board the size of a stick of gum with a round tube. These are the guts of the viewfinder. So now you need to take your multimeter. Set the meter to test for continuity.
(Be careful here! Though it is tiny, that round tube that you see is what can carry up to a 1500 volt shock if you touch it. I know this from experience...)
First, touch the negative probe to the metal enclosure on the board. This should be the common ground/negative connection. Once you have that, start touching the wires that you cut off or unplugged when you removed the viewfinder. At least one of the wires should make numbers jump on the multimeter screen. This is a wire with continuity. Stay steady and try to get a constant reading on the screen. This constant reading on the screen should be saying any number between "5" and "12". This is the voltage of your viewfinder. Write this number down, because you will need it later.
Now, tape off the wire that you found the continuity on. This is the positive wire.
Step 6: Power Applyed
Seeing that you have identified your positive power wire, take your power supply and set it to provide the number of volts that you wrote down when you found the positive wire. First, touch the negative wire to the negative wire, and apply power to the positive wire that you taped off. If done correctly, you should see the tiny view screen light up!
Step 7: Composite Input
Now is the fun part. To identify the composite input, you need to take the RCA cable and cut off one of the plugs. (e.g. The red plug.) Now strip the plastic cover off so you can see the copper ground wire. You will also see another wire inside of the ground wiring of the RCA cable. Strip off a length of about halfway down of the cover on the inner wire. You can't have the two wires connecting in any way.
This is what the cable should look like: There is an RCA plug on one end, and two bare wires on the other end that are pulled apart. The inner wire is positive, and the outer wire is the negative.
Step 8: Soldering Connections
For ease of use, you should solder some new wires for your viewfinder. If you cannot solder, simply twist the two wires together and tape the connection.
So, for the positive input on the view screen, you might wish to consider using a red wire. Solder or tape it to the marked positive power input. Next, use a black wire for the ground connection. Do the same here and then hook up your newly soldered (Or taped) cables to the power supply. If you see the screen start glowing, you did something right. Tape the connections individually to prevent a short circuit from happening!
For the composite input, take the RCA female-female splitter and cut off one of the female connection wires. Strip back the wire covering opposite the female RCA connector. You will see some copper wire, move it out of the way and strip about half of the inner wire you see.
Now take the inner wire that you stripped back and solder it to the composite input that you identified. Tape the connection to prevent the wire from short circuiting with another. Then, solder the ground wire to the same ground that you tested the power of the viewfinder on.
(For a visual aid, look at the included picture in this step)
By using the female RCA connector, you can simply plug in a RCA male end. (Like from a DvD player)
Step 9: Put It Back Together
Now that you have tested and proven that the viewfinder works with its new video input, go ahead and reassemble it. Simply reverse the process of taking it apart and make sure to fit the new wires into position. Return the lenses so you can view the screen up close. Now tape the wires in place that are on the outside. You are almost done!
Step 10: A Custom Power Supply
So now you have your mighty fine view screen and are ready to make it into a wearable! But... you need a power supply that you don't need to keep plugged in.
If your new viewfinder only needs 5 volts, you might want to consider a usb battery. It doesn't weigh much, so it is a viable option. You would need to wire a usb cable to the power input, but make sure that you put the wires where they go.
If you need a 12 volt pr under supply, you should consider a laptop battery, provided it is regulated to your power needs and is of a DC current.
I made a costom power cable from an old RCA female splitter. (Seen above) I can hook this up to a USB cable and simply plug it in when I need it.
Step 11: Enjoy!
Now you can watch movies in the car at night without distracting the driver, monitor I/O inputs on the Raspberry PI, hook the apparatus up to a Plug and Play console... Look cool walking aroung the local hippie hangout. The possibilities are endless if you can think of it!
Please leave a comment and a like if you enjoyed this tutorial or even made your own! See you in the next Instructable!