Thank you for the explanation.
QUOTE (blst @ 16 Jan 2005, 21:22)The speed is coded in two parts, synchro and data. the "barrecode" is printed on a silver sticker for a better reading.
an IR transmeter and receiver read the code and transmet it to a decoder (pic for exemple) who drive the motor by PWM.Yes, I get the picture.
There are a couple of points regarding our CarDCC car controller prototypes:
1) The current design won't support the described functionality, as there is no IR receiver on the car controller. It would be possible to make another design that could implement this feature though.
2) If you want to reuse the IR transmitter for both lane change sensor and speed sensor, you have to place the barcode on the bottom of the slot. I suppose it could be done, but you need a reflective detector wit a long focus range (about 10mm), and you might have trouble getting reliable performance on curved sections.
3) If you want to place the barcode closer to the sensor (i.e. on the track surface), you need a seperate IR transmitter and receiver. This can also be done, but you need a processor with more I/O's.
There is also a possibility with the CarDCC system: if we use the guide blade to code the cars with different slits in the guide blade. Not only could the lane change controller detect the car-id and the time of passing, but using the absolute timing between the slit pulses, it could also calculate the speed of the car.
This could then be sent to the track controller together with the timing information. You could either implement the ghost car algorithm in the track controller, or the track controller could send it to a PC, that could implement the algorithm and handle the ghost car control real time.
If you want to experiment with this on your own, you should feel free to use the system specification and interface protocol specification from the CarDCC project. That will allow you to use the other components, like track controller and lane change controller, without modification, and just focus on a CarDCC compatible car controller.
Good luck with your project.