Built in 1987, my original car computer was an Atari 800XL that sported a blistering clock speed of 1.79mhz with a spacious 64k built in, a 5-1/4" floppy drive sporting 127k of storage space.看 The 800XL was a perfect candidate for a car pc due to it's all-in-one construction.http://www.atarimuseum.com/computers/8BITS/XL/800xl/800xl.htmshapeimage_2_link_0
The 800XL was installed in a Dodge Shelby Charger - a 2.2 liter turbocharged hatchback based on the Dodge Omni 024.看 7.8 zero to sixty doesn蘗t sound very sporty these days, but for a kid on a budget up against K-Cars and Chevettes, this car was a thrill a minute and with 205/50-15蘗s on it, it handled better than any live axle car on the road.


Of course, it being American, if fell apart after 104,000 miles and had to be sent up to that great Carroll Shelby stable in the sky to live among its more honorable peers.看 It was the first real performance car I owned.看 Actually, now that I蘗m married, I suppose that it probably the last performance car I蘗ll ever own!

The 800XL didn't even require a disk drive to boot.看 BASIC was built in and from the time you threw the switch to the "Ready" prompt was perhaps 5 seconds.看

There was no monitor on the Atari -you used your television set.看 In the car, I found a monochrome 12 vo
lt CRT and installed it in the car in place of the entire center console -from that silver cigarette lighter under the radio down to the gear shift, I built a matching enclosure for the CRT.


Below right, you can see the actual computer in action.看 This shot was taken with a slow shutter speed, revealing the scanning of the CRT.看 I蘗ve enhanced it with Photoshop but the numbers and text are accurate.

Software

The display is divided into a couple of sections - a display of your average speed over a series of times, a sectio
n that tells you how fast you have to drive to get where you want on by a certain time input by the driver at the start of the trip and a trip/countdown odometer.看 The entire application was written in Basic and would write the average speed each minute out to the floppy disk drive.

Yes, the speeds on the screen are accurate.看 This photo was taken at speed during an annual "rally" that my friends and I used to run between Annapolis, Maryland and Niagra Falls, Canada - The "Annacan" rally.看 We go the idea from the infamous Cannonball run rally.

Interface with Car

The XL was essentially a rally computer and was connected to the speedometer of the car using a custom digital circuit built by my friend, Jeff Makey.看 Using an infrared emitter and detector from Radio Shack, we bounced the IR beam off of the rotating cuff of the speedometer.看

Using the transmission gear ratios, we figured out that the car traveled 2.4 feet each time the speedometer cable made a half turn and since the speedometer cuff was two sided, there were two opportunities to detect the beam each rotation.

The circuit counted how many times the speedometer turned and held the results in memory on a wire wrapped breadboard that connected to the Atari via a parallel port.看 The computer would perform its tasks and then send a query to the circuit to see how many times the beam had been detected since it last checked.看 Since it knew how long it had been since it last checked for the count, the program could do the math and display the results on the screen.

Average speed for each minute was sent to a file on the floppy disk drive, which also conveniently ran on 12 volts.看 At the end of the run, you could print the results out to the dot matrix printer, an Epson FX-80 that had to be plugged into an extension cord for 110 volt power.

Built for Speed

The install was built specifically for the "Annacan" (more detail on this page) rally, an Annapolis, MD. to Niagara Falls, Canada rally that was inspired by the Cannonball Run cross-country rally.

Held in 1984, 85, 86, the Shelby participated in the 1986 rally as my friend Chris and I sought to break the so-called 6 hour "barrier".

Using the computer, we reasoned, would allow us to keep up with whether or not we were making progress on the goal.看 It worked great.看 We finished the 424 mile journey in 5.91 hours, eclipsing the previous record.看 The computer was a success and at the time was a very big wow! factor.