Building the Ultimate Kid's Computer

Davin enjoying his new computer.

Like a lot of kids, Davin started using a computer when he was very young. And like a lot of parents, we want to encourage him. When he was three, we gave him a Vtech V.Smile game console, but by four, he had begun to grow a little bored with it, and was wanting to use a real computer more and more. We decided that he needed one of his own.

Curiosity is, of course, a good thing for a child to have. Unfortunately, Davin's was leading him to explore the computer itself. He was disconnecting cables and pressing any and all of the buttons he could find. This meant that most of his sessions with the computer ended with the machine inoperable. Switching the power on an off quickly, or at least before Windows completes its shutdown, will usually cause a PC to hang, and demand attention before it will operate again. Additionally, there was some danger that he might hurt himself, playing with the power cord.

Searching for a solution, I found a variety of computer furniture designed for children. However, all of them, even those intended for very young children, leave the computer and its cables exposed. Unable to find what I wanted, as a commercially available product, I started thinking about creating one from my own design. Unfortunately, I didn't have any proper woodworking tools. Even worse, I didn't have any real woodworking experience. On one hand, I thought it could be a fun, possibly even relaxing (if kept in the proper perspective), learning experience. On the other hand, I was concerned about how much it might cost. Eventually, I convinced myself to do it with the rational that the new skills and tools would come in handy in the future.

To learn more about woodworking, I bought several books on the subject. The cost of which turned out to be well worth the investment. I was looking for a book that was well illustrated and would work as a reference that I could quickly look up a particular topic. Although I wasn't able to find a single book covering all of the topics I felt I needed, I found a series of books published by Taunton Press that fit my needs. "The Complete Illustrated Guide to Furniture and Cabinet Construction," by Andie Rae, as the title suggests does an excellent job of providing a detailed overview of furniture and cabinet making. "The Complete Illustrated Guide to Joinery," by Gary Rogowski, covers joinery in much greater detail. As I didn't want to spend a lot of time building something, only to ruin it by botching the finish, I searched for a book about that. I found one in "Tauntons Complete Illustrated Guide To Finishing," by Jeff Hewitt – also of the same series.

System Signals Block Diagram

Like a good systems engineer, I started by creating a list of requirements. The first requirement was that the computer components and cables would to be fully enclosed. This led to the first derived requirement, which was that the cabinet would prevent overheating. The next requirement to be added was that on/off control be restricted to administrative privilege.

ON/OFF Keyswitch (Roll mouse over for location)

I knew that Linux allows setting the permission level required to shut down the system. This can be done at the keyboard by logging in as the user with that permission or via SSH through the network. On most PCs, the On/Off control takes the form of a momentary contact switch on the housing. This is connected by wire leads to a header located on the motherboard. I mounted a Key Switch with momentary contacts to the outside of the cabinet, and connected this to the motherboard, in place of the switch on the PC's case.

Davin wasn't quite ready to part with his V.Smile console. It requires a television, with a composite video monitor input, for a display. We had donated the little analog TV he was using with it, before we moved from the bay area, and didn't want to replace it. Connecting his computer to our network, he would be able to access any of his movies that might be stored there, as well as live TV programming from the network tuners. Doing a little internet research, I found the Hauppauge 558 ImpactVCB PCI Video Capture Card to accept the composite output of the game console. VLC, which runs on Linux, can display video from this card. We also have a SiliconDust HDHomeRun, which is a dual HD TV tuner connected to our home network. Running VLC, any computer on the network can access the live HD stream from either tuner. All of these functions can be programmed to launch by clicking a desktop icon.

I sketched up several fun designs. I am sure, any of them would have thrilled Davin, if possible to build. Several, like the one resembling the space shuttle, were outrageously impractical. After getting all of the really crazy ideas out of my system, I came up with a simple design. Davin already had a work table with two matching chairs. I decided to design the computer cabinet as a complement to it.

Monitor Compartment Warm Air Exhaust Fan (Roll mouse over for location)

A Samsung SyncMaster 920WM 19-inch LCD Monitor mounts in an enclosed compartment, at his eye level when he is seated at the table. I was concerned that a monitor without its own fan, on a warm day, would overheat. The compartment should have forced air ventilation to prevent this from happening. The fan would mount in the top rear of the cabinet to draw air through the compartment housing the monitor. Most small fans are DC powered and require a power supply, but I found a small quiet AC powered fan. A vent mounted below the monitor allows cool air to be drawn in.

Monitor Compartment Cool Air Intake Vent (Roll mouse over for location)

The lower compartment houses the CPU. Typically CPUs rely on the power supply fan to draw air in push air from the power supply through the larger enclosure. It would be difficult to match the CPU intake with a vent opening in the cabinet. A seemingly simpler approach is allow air to freely enter and circulate throughout the compartment. Using steel grills in place of solid door panels limit access while allowing the free flow of air.

Smart-strip (Roll mouse over for location)

A Smart Strip LCG3 allows the control of power for a set of devices by sensing the power drawn from one outlet. Originally, I expected to power the CPU from the sensing outlet, thereby shutting everything else down when it was either in sleep mode or off. However, I discovered that the power consumption of the CPU, is too low to reliably activate the other outlets. The power consumption of the LCD is significantly higher, and it does reliably control the other outlets. In Linux, the power saving modes can be configured to blank the video signal. When the LCD goes into power save mode, power to the other peripherals, including the monitor compartment cooling fan is turned off. The CPU is connected to an outlet that is always on. This allows the the CPU to wake up on LAN activity, without waking the monitor or powering on the other devices.

After making several sketches, I realized that the design was complicated enough that it should be drawn accurately. QCAD Community Edition is an open source free 2D drafting application that runs on Linux. It is also fairly easy to learn.

CAD files are available. Download the files in .zip, .tar.gz, or .pdf format.

Another important requirement is that the end result be aesthetically acceptable. With little prior furniture making experience, I wanted to keep my goals reasonable. Fortunately, if things didn't work out well, it could be hidden away in my son's room. A fun design would make my son happy, but I was a little nervous about my wife's reaction if it went horribly wrong. Eventually, I reasoned that I could declare success if my son liked it, and I achieved something vaguely recognizable as furniture, while not causing our insurance premiums to increase.

I didn't use any exotic materials. All of the wood was purchased from a home improvement store. The vertical side panels and horizontal flat surfaces were made from particle board (MDF) shelves. These are available in conveniently short 48" lengths that can easily fit into a small car. I used 3/4" x 1 - 1/2" and 3/4" x 2 - 1/2" poplar hardwood boards to make frame members. I bought a mitre saw to accurately cut the hardwood pieces to length, and a doweling jig to help create the joints.

Assembling Frame Members

I used red oak wood to make the monitor support, and discovered how difficult it is to work with this wood. This was the only thing that seemed to challenge my new rechargeable Ryobi saw. Looking back, the heftiness of this piece is probably over kill. I probably could have used a lighter wood. The monitor attaches to the support with a tilting VESA mount. This allows the angle to be adjusted, and the monitor to be easily removed, if necessary.

Monitor Support (Viewed from rear of cabinet)

Polycarbonate sheet forms a protective window in the front of the compartment housing the monitor. Specialty plastic supply stores sell sheets of this material in a variety thicknesses, and will cut it for you. I have also seen it for sale at some of the home improvement stores. I created a frame from 3/4" x 1 - 1/2" poplar, on which to mount the screen protector. Threaded inserts allow the screen to be secured to the frame by small bolts. I used a special plastic cutting drill bit to prevent the sheet from cracking. To create the speaker openings, I used a 3" diameter hole saw, and epoxied fiberglass window screen material to the back, to cover the speaker holes.

I masked off the viewing area, and painted the back of the screen with black spray paint to create a frame around the edges. This hides the monitor's bezel. This turned out to be more challenging than anticipated. Several coats are needed to get a truly opaque cover, and allowing too much paint to accumulate at once will cause it to blister. Masking tape doesn't provide a consistently strong edge, and paint was able to encroach at some points. Vinyl tape would probably work better.

Applying Primer

I thought over and researched several ambitious paint schemes, but ultimately decided to go with a simple single color glossy finish. I sanded the flat surfaces with my new finish sander. I used filling compound to smooth over the numerous small craters in the surfaces of the MDF and the joints. I followed this with three cycles of alternately applying grain filler, and sanding again when dry. I took Davin with me to the paint store to choose the color. He chose the very bright blue finish seen in the accompanying photos.

The total cost for material and hardware came in a little under $250 – see the last page of the drawings. That doesn't include paint, brushes, glue, sand paper, or any new tools. Of course, it also doesn't include any computer hardware, that if not for building the cabinet would be sitting out on a table. This was my first real woodworking working project. For my level of inexperience and tooling, I think this was a good choice as a first project. There are a few things that, if I had time, would go back and fix. I learned a lot, and was able to achieve presentable results. The comments from the neighbors passing my open garage door, were complementary, but the real reward was my son's happiness when I presented the finished system to him.

The Finished Product

The ordinary black mouse, seen in the photo above, was a temporary replacement for my original choice of mouse, which broke after only a brief time of use. I replaced it and the keyboard with devices sold under the Crayola brand, and have been very satisfied with them. A small mouse is easier for a child's hands to grasp, and the bright colors make it attractive and enjoyable for them to use. The Crayola mouse is colorful and smaller than an adult sized mouse and features a bright flashing multi-color LED. Additionally, it has a unique water filled transparent compartment. The Crayola keyboard is also colorful, and has fewer and larger keys than a typical adult keyboard. This makes it easier for young children to identify the keys.