Camcorders (those bulky things that dads used for recording birthdays in the '80s and '90s) are all but obsolete these days thanks to smart phones. That doesn't mean they're totally useless though. They can still be a great source of parts for other projects. One of my favorite items to harvest from them are their cathode ray tube viewfinders.
CRT viewfinders are a great way to add interesting flavor to projects because they're so unlike anything else in modern consumer electronics. It's a vacuum tube powered by thousands of volts that displays pictures. How cool is that?
I was recently given an old camcorder by some acquaintances, and when I saw it came with a CRT viewfinder that worked, I knew I had to some up with a project for it.
I didn't quite have a full vision for what I wanted out of the project when I got started, though I knew I wanted the CRT to be the centerpiece -- not just the screen though, the entire tube. I toyed around with putting the CRT under a bell jar, but eventually I settled on doing something with freeform wiring, aka dead bug wiring, aka Manhattan-style wiring. I was inspired in this by the Lethal Nixie Tube Clock and the creations of Mohit Bhoite.
Here's how I got started, how I took this project to completion, and how you can come up with a freeform creation of your own.
Step 1: Find a CRT Viewfinder!
First things first. You need a CRT viewfinder, so that means you either need to find yourself an old camcorder or you need to head over to eBay to buy a viewfinder on its own.
Camcorder viewfinders come in basically two types: CRT or LCD. Older camcorders almost always have a CRT viewfinder, which can be identified by looking for an arm-like appendage with an elbow sticking off the camcorder. LCD viewfinders are flat and usually fold against the body of the camcorder when not in use.
I got my viewfinder when some friends of a friend gave me an early 1980s Canon camcorder after I helped them get rid of a big projector TV. The camcorder seems to be broken, but the viewfinder worked like a charm.
Step 2: Preparation
To get started, I stripped everything off the CRT that didn't need to be there. I didn't take pictures of removing it from the case, but it was a simple matter of removing a few screws and popping the plastic open.
The trickier part is figuring out which wires you need and which ones you don't. Some viewfinders are really simple and have only wires for power and the video signal. Others, like this one, have a bunch of other things attached to them. @devicemodder put together a thorough tutorial on figuring how which wires you need. Go look at it. I found it very helpful.
When your viewfinder is stripped down to the bare necessities, you're ready to put on your artist's hat.
Step 3: Freeforming Your Creation
Now it's time to get creative. For my project, I used 1/8th inch brass rods I picked up from my local hobby store. Brass rods are a nice material to work with because they're straight, relatively rigid, easy to cut with standard wire cutters, and easily accept solder. They're also easy to bend using pliers, your hands, or, as I prefer, round-nose jeweler's pliers you can get from the craft store for about $10. There are other options besides brass rods, however. You can use solid-core copper wire without insulation or pre-tinned wire. As long as you can cut it, bend it, solder it, and it holds its shape while conducting electricity, it will work.
I decided to build a simple box, so I began by laying out a frame around the CRT and its PCBs. From there, I settled on a height for my creation, and cut the vertical rods.
To solder the rods together, you can use a soldering iron, or a small butane torch. You'll definitely want to use flux to make the job easier. Plumbing flux does the job really well, but it has to be removed when you're done or it will eventually start corroding your brass. I prefer to use rosin paste flux, which you should be able to get from your local electronics shop.
Step 4: Your Imagination Is the Limit
The important thing to remember here is that this is your creation, and it can take any shape or form you want. I chose a cube, but you could make a cylinder, or a dodecahedron, or geodesic dome. And since this is freeform, you can substitute the brass rods for wire in just about any part of your circuit. Solder an LED onto a pair of rods and have it stick up like a mast, or use the rods to power a speaker and hold it in place. Your imagination is the limit.
If you choose to do what I've done, look for a CCTV camera rather than a webcam. A CCTV camera outputs a composite video signal, and that's what your CRT viewfinder is built to understand. You will make things a lot easier for yourself if you also make sure you get a camera that runs on the same voltage as your CRT. My CRT needed 12 volts, so I got a 12-volt camera.
Once I had the PC board for the tube and the tube installed in the brass frame, I started working on adding the other components of the circuit: An on-off switch, a battery pack to supply power, a small CCTV camera I got off Amazon for $11, and a red LED to show when the switch is flipped on. I can't tell you exactly how to wire your creation because that will depend on which components you choose to use. You might use motors, solar panels, seven-segment LED displays, an Arduino, a 555 timer, or something else entirely. Just have fun!