[Xlot]

Since the issue keeps coming up from time to time, this

www.geocities.com/OzDCC/

is the best explanation I've found so far

In short, I understand that :
- you start with DC (say + 18V)
- you chop it to form the digital "message"
- what goes out is a rectangular wave +/- 18V
- the car decoder reads the message(s) - speed and lane change
- perhaps the wave is rectified back into continuous +18V DC before going to the decoder chopper, which determines the output voltage to the motor

If this is all correct, kids had definitely better NOT lick both rails at the same time !

Beppe

 

[Xlot]

Er... , electronics is not my area of competence at all, so I do recommend you look up that Australian site (I don't know why the link did not come out active....)

As a former electrical engineer, I can say that AC (single phase or 3 phase) is classically considered to be a current that varies following a sine wave, at a fixed frequency - so I wouldn't consider the DCC shape as AC

The one thing I've grasped is that DCC was adopted by model trains because the environment is electrically very "noisy" - so that if you classically superimpose the control signal to power it will be drowned out - with DCC, signal and power coincide

Hope this helps a bit.... at the moment, I'm just too excited from astro's revelation of Scalex having used "my" method for LC activation !

Beppe

 

[Xlot]

I'm glad the thread is now in much more capable hands
Just two notes :

- I gleaned that the legal frequency limit to avoid EMI is 10 kHz - this comes from a Finn, Julius Wilkko a.k.a. lordjw, who as a matter of fact would be a very nice addition to SF's talent pool

- as for the maximum number of cars compatible with little response delay under DCC, I'm a great believer in the bumblebee theory (I suppose you know it) : since Davic runs well with 15 cars, I'm not worrying

Beppe

 

[Xlot]

GREAT to hear from you again Julius !!

Look, we need to talk about a number of issues, which I beleve will lead to the much desired open source/ NMRA environment (you listening, Thomas ?)

The starting point is that Scalextric have adopted the LED emissor principle for lane changing. It's totally immaterial whether they saw my proposal or if they thought of it concurrently, what matters is that I believe the concept is not patenteable, and they have proved that it works - so this can be adopted universally
(OK, my only doubt is that there may be an even simpler method - Tropi was hinting darkly at ball-less, wireless optical mouse technology)

The next point is signal coding - it's not as essential, personally I'd be happy to live with a Scalextric monopoly - still, it would be nice if people could make aftermarket decoder chips
Here, I'm absolutely out of my depth - since you already mentioned it, could you elaborate? Oh, and are you saying that Scalextric's might not be DCC as we know it ?

Another point is lap counting : until now, nobody has been able to tell me how SCX and Scalextric make it work - any clue ?

Finally, how do you see your RF link alternative in this context ?

Ciao
Beppe

 

[Xlot]

Julius,

fascinating reading about Generics (although they could have chosen a better name !) - one does feel the might of Scalex's power - but not to worry

OK, so we can live with a Scalex monopoly for the electronics package, at least for the time being - I do not believe price will be an issue, remember slot racers are not the target - toy buyers are, witness the reasonable price of SCX's Digital set
In this respect we are fortunate in being a minority, not like model trains, where DCC cost is significant

But the main implication is that LC operation is independent of the DCC control unit - this means that any track manufacturer can get into the business with a minimum investment, just by developing its own LC track piece - and since track manufacturers also make cars ....

So, come 2005 I can see a lot of clubs converting their 6 laner to a (much longer) 2 laner, with plenty of track left - too bad that corner marshalling effectively limits layouts and the number of curves you can have

Beppe

 

[Xlot]

Come to think of it, Julius, there's got to be another way for the lap counter : Scalex has no second LED, and SCX no LED at all !!