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Hi guys, forgive me for my simple lateralism, but as a musician, when I hear the term PWM, (Pulse Width Modulation), I immediately think of sound generation & synthesisers.

following this thought leads me to the question;

Is there a way to record the output from the RS plug on the SSD base station via (need help here) modem, and/or audio recording so that one could simply playback this stream into the mini-jack controller inputs to create ghost car functionality.

IE: record yourself driving and then playback that stream of information.

Any thoughts?
 

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interesting idea.

the PWM is the signal on the track. Unlike analogue, this is not the signal going through the controller, which may be modulated, but may be DC.

In theory you could record the track signal, as long as the audio sample rate exceded the track frequency quite significantly. (The audio sample rate needs to be twice the maximum frequency of audio, but the filtering would play this frequency back as a sin wave, not the digital square wave. Experimentation would be needed to see if the chosen audio PWM frequency was of high enough resolution to render the square waves sufficiently for the car decoder chips)

When this is played back, a power amp with sufficient power and gain would be needed.

But the track signal is multiplexed, so when you recorded, you would record the signals for all the cars, not just one.

The idea of recording the controller signal is more fruitful, but if the control signal is DC, it will not record well with conventional musical equipment. Furthermore, playing it back into the system will need some investigation, as simply sending it down the jack plug would be replacing passive resistance with active power....

Another point is, the longer the race, the greater the error of acceleration points relative to car position. Any difference in wheel spin, motor behaviour, bearing friction will cause the car to travel a slightly different distance when the identical signal is replayed than when it was recorded. This may end up with the braking not matching the curves.

Just some ideas on the supposition
 

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drummer,

Don't know if these will help or not, but this is a site I bookmarked quite a while back for my DCC model railroading stuff.

http://www.robh.nl/digsoft.html

There's some software for protocol and PWM analysis and monitoring in there. No idea if any of it will be helpful, since I never got around to the project that led me to bookmark it.


If it's helpful, I'd be interested to know what you did with it. If it's not, then..erm...uhh...it's someone else's fault. yeah, that's it.


/gb
 

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Yes folks there's some very interesting stuff out there for DCC model railways, I just knew I'd find interesting things if I persisted in the spirit of 'not waiting for Scalextrics digital Challenger/pace cars solution'.

ON my site there is a ZIP file which contains a small program and help file.

In short it says it'll will do what I postulated at top of this Thread. (!)

Dont know what help it may be to anybody (including me) but just wanted to keep those imaginations fired.



BTW;
Not the being electrical type, can someone tell me what the 2 triangular symbols between the two power leads represent?

Here's the link to the file.
ShowDCC

cheers all
 

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Hey Drummer

They are diodes buddy the only allow current to flow in one direction and you can grab them for a few cents at dick smiths or jaycar

Dont worry bout what one to get just somthing small in fact you can probably use dick smiths signal diodes for 6c each

If I come down again before youve got them I'll bring a couple

Catch ya
Pete
 
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