Precision Scalextric Lap Timer

Accurate to 1/1000th second, the Precision Scalextric Lap Counter & Timer is much superior to the standard Scalextric model. Compatible with any modern computer that can run a web browser. Produces a graph of lap times, not just the basic info produced by the standard Scalextric model. And, you can try it here (see further down this article for instructions)

More Info I've been playing Scalextric quite a lot recently with a few friends. Great fun, but I was dissatisfied with the existing lap timer manufactured by Scalextric - it is only accurate to a tenth of a second which is a bit crude when average lap times are around 5 seconds and it only displays a lap count and current fastest lap on a basic LCD display. Scalextric also sell a "Race Management" software package, but this is also very basic and doesn't begin to tap the potential for this kind of software. There are a number of open source Race Management systems available but these seemed complex and ugly. I decided to make something better :) (If you don't want to read all my self-congratulatory drivel, you can jump straight to trying the software here.) Keyboard MembraneMy idea was to take the controller from a USB keyboard and hook it up to some magnetic leaf switches hidden under the track. When a Scalextric car passes over the switch, the magnets in the car trigger the switch which results in a key press been sent to the computer via the USB. The keypress is then counted by some software running on the computer. One great advantage to this approach is that since I'm using a standardised bit of existing hardware I didn't need to write any extra driver software to interface between my software and the track. Also since the device sends it's signals using key presses I could develop my application in a web browser using html and javascript making it instantly compatible with any relatively modern computer (or for that matter, even a mobile phone). This was one of the those rare projects where everything seemed to work first time. It took me about 3 hours to extract the "brain" of the keyboard, "decode" it's internal wiring and solder it up to the magnetic switches which successfully fired either a "Q" or an "A" when I passed a fridge magnet over the track. Another 5 hours and I'd hacked together some basic software to time the laps, accurate to at least a 1/1000th of a second and display a nice graph plot of all lap times over the course of a race. Version 1 lap timerFrom pipe dream to reality in 8 hours - an inspirational first for me :) ! Unfortunately, the first real test was a bit of a let down. The timer worked great with cars going slowly but didn't work with cars whizzing round the track at full tilt. Having got this far, I wasn't going to give up. After a bit of thought, I decided that using infra-red beams to detect the passing of the cars would be the best solution as there would be no mechanical contacts to wear out or interfere with the cars. Interfacing some infra-red photo-diodes with the keyboard controller was more difficult than wiring the leaf switches and required some experimentation and "bread-boarding" with inverters, resistors and relays. However after a few days and a number of trips to (my new favourite shop) it actually worked. This is the first electronic device that I've designed and then actually made so I was pretty excited ! We've been using the new timer for a few weeks and I've made a few enhancements to the original hacked-together software. One advantage of the software being "browser-based" is that I can publish it online and you can try it out for yourself here. You can press "Q" and "A" on your computer keyboard to simulate cars triggering the lap timer - admittedly not as much fun as real Scalextric but it gives you the idea of how the software works. If you like the software and want me to make you a lap timer I can currently make one for you for £100 GBP given a fair bit of notice and depending on my work schedule. Yes, this is outrageously expensive but I currently have to hand-make the timers which is extremely time intensive. If there is enough interest, I may find a way of getting the timers mass produced which will bring the cost down significantly. Drop me an email at or leave a comment on this blog post and I'll see what I can do.

Try my Precision Scalextric Lap Timer here

Note the software has been designed to be operated using a keyboard (although you can still use a mouse if you wish). Key controls are: 1 = simulate Track 1 lap ("a" also works) 2 = simulate Track 2 lap ("q" also works) n = new race (you need to press this before the software will start counting laps) t = about e = settings f = show times for the 10 fastest laps for each track Note that the first time you press "1" or "2" on a given race, the software doesn't actually record a new lap - it just starts the timer. This is intuitive when used on a real Scalextric track (ie the cars cross the start line) but not so when "testing" the software on a keyboard. Also, note that the "Vroom" noise indicates a new "fastest lap"

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