QUOTE (Maltese @ 14 Nov 2004, 02:26)While waiting for the guys who did the video to respond...each car has a "receiver" looking for a certain frequency. When it hears its frequency it does what it is told...like having five portable radios in the same room on the same station.
The hand controller does not handle the voltage, the box does. The same voltage is sent all the time roughly while the signal to the car tells a device in the car how much voltage to allow through to the motor...thus speed control.
...I now await a well-rounded correction from Tropi or Astro which I probably deserve.
<{POST_SNAPBACK}>
Its a pretty good explanation. The radio analogy works... but you guys are like... so analog
Each car has an numeric ID corresponding to a controller (your 'frequency' above) You assign a car an ID at the start of the race.
Data is sent along the track in 'packets' and each car keeps checking each packet, disregarding any that are not 'addressed' to it. When it receives a packet that is addressed to it it reads the data in that packet. I imagine the packets are pretty simple and pretty small since the ID can only range from 1 - 6 (0 - 110 binary, only 3 bits needed there!) and there are only.. what, 3 opcodes : change speed, brake, change lane. Each of those opcodes will also be a number (cos that's all computers understand kiddies!), so lets say in our imaginary system change speed is 01, brake is 10 and change lane is 11.
In such a system a typical packet would look like this:
0001 0001 1000 0000
So from left ot right this packet says
0001 This is addressed to car number 1
0001 Command is accelerate/decelerate, next byte contains value...
1000 0000 Speed value is 128
I am not saying the Scalextric system is this, this is an imaginary over-simplified explanation, there will definately be more overhead in each packet in a real system (like a checksum so the car can ignore damaged packets) and speed may be expressed in 2 bytes etc. The more bytes used the finer the control.
Astro is right that the system will keep sending the message until the message changes basically, nevertheless its theorectically possible that all your brake messages could 'screw up'.. just extremely unlikely. Still, I think its inevitable that sometimes 'weird ****e' will happend, just as it does with CD's and DVD's and computer programs. Of course analog has its own 'weird ****e', just like static of old was replaced by pixel artifacts, so will 'my car flies off the track whenever the other guy's does' get replaced with the infamous 'every time I put three minis and an audi on my circuit the minis all flash their headlights and do 360's!" bug...
...only kidding