First, what devices to use? We considered many things, such as a salvaged camcorder, a bumper-mounted camera as used on RV's and large vehicles, TV's that are mounted in the back of a car headrest, handheld TV's, a small laptop, and so on. After some exploration we decided the best (and most economical) choice was a small webcam from Pixera and a 5" LCD monitor from Parts Express (an excellent source for electronic supplies). These are pictured out-of-the box on the left. The screen is only a quarter-inch thick, perfect for a front-mounted display. And, it is high-res and IN COLOR! This was convenient for several reasons, most importantly that the screen and camera both "spoke the same language" without need for computer hardware to translate between the two. They both use RCA, and plug directly into each other. Finding an RCA webcam was difficult because most are USB these days, but Pixera came through for us. Finally, these devices were in our price range. Finding an LCD screen priced at $100 or less was also tough (again, Parts Express is great!). The only drawback of the cheap monitor is that it lacks a cover and the circuitry is exposed on the back (see above). After tax and shipping, we spent a total of only $200 on the equipment!

Once the devices had been obtained, we next needed to decide how to mount them. Jesse has kept systems on his chair "modular" by using velcro to hold each in place, allowing him to swap things in and out as needed. For the screen we needed a mounting brace that could be attached by velcro. We considered several shapes, such as a wishbone or football goal post, and settled on a goal post with a large supporting base. After developing a scale drawing of what we wanted, we took it to the Radio Astronomy machine shop, selected a piece of metal, and cut and bent the bracket, as seen on the right. The camera will be held in place by velcro alone because it is small, lightweight, and comes with its own mounting bracket.

Next, we mounted the screen onto our bracket, as seen on the left. At the base of the bracket we attached velcro so that it can easily swap in and out of Jesse's system.

Now that the monitor and camera are ready to be attached, we needed to power them. Jesse's wheelchair operates on 24 V and his power source has a tap for adding devices to his chair. The screen operates on 12 V and the camera on 4 V. Again, the Radio Astronomy Lab assisted us and built the adapter on the right (bottom right of photo). Also we included a switch (top left of photo) so that Jesse can turn everything off when not in use.

The next step involved making the equipment weatherproof. In the Bay Area, you never know when a rainstorm will suddenly pop up. The monitor especially needed weatherproofing because of the exposed circuitry on the backside. Our goal, besides waterproofing it, was to keep the monitor still easily visible, as well as aesthetically pleasing. We considered a variety of alternatives, including a vinyl (like car upholstery) sleeve with a transparent window, scraps of leather, a plastic enclosure, an acrylic box, and so on. We settled on the acrylic box because it was easily manufactured (by an associate of the Astronomy department), durable, and very transparent (see right and below). The bottom of the enclosure was left open to prevent condensation on the inside.

Finally, it was time to mount the system to his wheelchair! With the acrylic box encasing the monitor, the whole unit had become fairly heavy. Attaching it with velcro, as originally planned, was no longer a viable option because the velcro wasn't strong enough to hold up that much off-centered weight. We eventually decided to attach the monitor using bolts. The camera and on/off switch were still mounted with velcro. See below for pictures of the final product.

A monitor with this resolution has the capability of supporting more than a webcam. Perhaps our next project will be a small computer, or GPS, or something similar.

We have also considered multiple cameras, with a switch between the two, so that Jesse can have one aimed high and one aimed low. Or, a more fancy and more expensive solution is to buy a remote-control camera swivel mount.

Many thanks again to the machine shop and Radio Astronomy Lab for their important contribution to this project!

Please email me with questions, comments, and suggestions.