If you're wishing for a document camera and have an overhead projected that is ready to be retired, you're only 30 minutes away from getting your wish.
At my previous school, in New Mexico we were able to purchase a handful of Elmo document cameras and detail them to some of our teachers' classrooms. Many teachers became interested in acquiring more of them as soon as possible. In the meantime, we came up with a stand-in.
As is often the case, there were many overhead projectors throughout the school in various states of disrepair. Having a spare webcam, I did some research and came up with a cheap alternative to a document camera. If you already have a projector and laptop, then all you need is a decent webcam and an old overhead projector. Here's the plan:
Materials:
- Mid-range webcam - I picked up a Logitech Quickcam Communicate STX at Goodwill for $20.
- This does determine the quality of your picture, but remember you don't need it to be full-featured device. Microphones, face detection, etc, would be superfluous.
- Laptop (with a video out)
- VLC Media Player
- Digital projector w/ video cable
- Overhead projector
- Ensure that the projector is slated for the garbage or recycling as you will be dismantling part of it.
- Extras
- Zip ties
- Reading light
- Remove the mirror and glass from the unit on the projectors throw arm.
- For my projector, all this meant was pushing in two clips and pulling the box apart. I had to remove two pieces of glass and the mirror which reflects the shadow being projected from the projector body.
- Place the webcam into the unit from which you just removed the glass. You want the camera lens to face down at the projection surface. The rubber band in the photo is holding the cameras foot to its body.
- Connect your webcam to your laptop and your laptop to your digital projector.
- Install VLC Media Player, if you don't already have it.
- You need to add a script to VLC to get it to pick up what you're looking at through the webcam.
- Download the script here
- Run the .exe
- Here's where it can get tricky. The script needs to be modified to pick up your webcam and find vlc on your machine. Here's how it's done:
- the script will have been installed on the c: drive. It will have created a folder on your c: drive called "doccam". Find that folder and open it.
- Within, you'll find three files. The "document camera" with the nice icon gets moved to your desktop. The "copy" file gets left alone. All adjustments are made to the "docccam" batch file.
- Edit "doccam" by right clicking it and clicking "edit".
- A text editor will open and you'll see the file's code. Even if code gives you the chills, stay strong, it's very manageable.
- First, look at the fourth line and make sure that the filepath for VLC is typed correctly. By default, it will look for VLC in c:\program files\VideoLAN\VLC. In all likelihood this is where your VLC is located. On my current machine, I had to change "program files" to "program files (x86)". If you don't know where the vlc.exe file is, you can check it by finding VLC media player in your start menu or on your desktop, right clicking it, and clicking properties. The filepath should be displayed in the popup.
- Next, continue along the fourth line to the next piece of text. In this piece, you'll see the name of a webcam. Right away, you might notice that the model name written is not the name of your webcam. It is the name of the camera used by the person who wrote the script. This needs to be changed to the name of your camera. You can find your camera's name in several different ways, but the easiest is as follows:
- Open VLC media player
- Click the Media button
- Click "Open Capture Device"
- Under Device Selection, click on the button that reads "default".
- You should have some options; "default", "none", and your webcam's name.
- Replace the camera name in the fourth line with the name of your camera, exactly as it is written. If you follow the fourth line to its end, you'll find another instance where the camera name must be changed. It needs to be changed in both places. It is easy to miss the second one.
- Remember to save the file, leave it where it is, and move the "document camera" icon/shortcut to your desktop.
- If you did this correctly, then when you click on the icon/shortcut on your desktop, VLC should open and display what your camera is viewing. Give yourself a pat on the back, you just modified a script.
- Adjust the camera and throw arm on the overhead projector so that you get a good view of the overhead projector's projection surface. Place a piece of paper on the projection surface. If you have a small reading light to clip on (as I have in the pictures), or the camera has a light, experiment with their use to see what looks best.
- Finally, clone or extend your desktop as you would to display your computer via the digital projector. On your screen, you should see a full screen projection of what is on your overhead projector's projection surface. Zip tie your cords and clean up. If you have a desk or cart to keep this all on, that usually works best.
A big thanks to the Fried Technology Blog for some inspiration and a link to the VLC script. Fried also has links to plans for building a much more elegant document camera if you don't have an overhead projector.
I'll definitely be subscribing to your site. Keep up the good posts document cameras for teachers
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