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CarDCC hardware requirement specification

6K views 36 replies 11 participants last post by  Newbie1/32 
#1 · (Edited by Moderator)
Greetings fellow slot car racing fanatics


I've put up a draft CarDCC hardware requirement specification on a website kindly established by Randy Brown ... thank you for your kind help.


I'm hoping to get some feedback from you about what is god and what is bad, or alternative solutions that you feel would provide a better solution.

Please feel free to comment on any aspect of the proposed digital system.
Your help in making this system the ultimate slot car experience, is highly appreciated.
 
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#27 ·
Hi Soren,

One idea, if possible, would be having the option to wire the l/c's on there own circuit.

Say, for the person just getting into CarDCC with 3-4 cars, 30 feet of track, and 4 l/c's ,the l/c's would run off the track. If a person or club has 16 cars,140 feet of track and 10 l/c's, the l/cs can be wired off their own circuit on the controller.

This would help keep signal traffic on the rails at a lower value on larger layouts with multiple l/c's and cars, with less chance of corrupted or lost/skipped info(lap/sector timing).

Best of luck with your project


Sincerely,Gord
 
#28 ·
Hello Richard,

QUOTE Is PB0 switched between being an Input for Fault Status and Output for brake lights? Yes, correct. The rear lights are used as standard rear lights and also brake lights. in "standard" mode the lights are dimmed by a PWM to get a lower light intensity. In the pause of the PWM the output is changed to input to check the fault status of the H-bridge. During braking the PWM signal is set to maximum to get maximum light intensity.

QUOTE I am not sure what you would call it but the SSD Powerbase has an H-Bridge in the output stage driving both rails with antiphase signals. The 0 and 1 timings are very similar to DCC. (Is this what you call +xV/-xV ?) I think so. Guenter has made two graphics concerning the different data transmission standards.
The first one shows that the voltage at the slot is switched between i.e. +17V and -17V (x=17). This kind of transmission is used by the DCC systems according to NMRA.
The second picture shows the data transmission which is used by Carrera Pro-X. In this case the track voltage is either 17V or 0V.

QUOTE Is your Pro-X car controller electrically the same as Soren's but with modified firmware for the Pro-X protocol? The hardware will be similar but no exactly the same. It looks like it is difficult to get the H-bridge in small quantities here in Germany. And I think a half-brigde is also sufficient.

QUOTE Are you going to put both CarDCC & Pro-X protocols in the car at the same time? I am not sure if there is sufficiant FLASH memory available to keep both protocols. But I will include a possibility to upload different firmware versions.

Regards

Juergen
 
#29 ·
Hi Richard

QUOTE (RichG @ 1 May 2005, 12:09)Have you, or anyone else, enthusiasm for a SSD compatible mode for CarDCC.I think it's a good idea.

I haven't given it a lot of thought, because I don't know very much about the SSD dataformat.

I agree though, that the only difference would be software. We're planning to build a software download facility into the CarDCC track controller. This could also be used to load new functionality into both track controller and car controller.
QUOTE Alternatively the CarDCC car controllers could be used with the existing SSD Powerbase with the benefit of better performance and control.That should not be a problem seen from the hardware point of view. You'd only need to adopt the SSD protocol and add the transmission of the IR-LED identification sequence.
QUOTE What do you think, could be a best of both worlds way forward?It certainly could.

I'm currently working on the CarDCC protocol, but a SSD compatibility mode would be a nice feature to add. It should be possible to make software versions for both CarDCC, SSD and Pro-X compatibility. That way every user has full flexibility from the same hardware.
QUOTE On the cct is the PWM signal for the rear lights generated in the microcontroller, and then brake from the motor driver?Correct, but the the motor driver brake signal is generated in the microcontroller and fed to the motor through the motor driver.

The only motor PWM signal that is automatically generated in the motor driver hardware, is the automatic overload protection system. It has priority over the PWM controls from the microcontroller.
QUOTE I realise you can add a lighting controller to the car if more inputs and outputs are needed but I feel that more inputs / outputs in the base controller would be of benefit.I agree.


With the current design I have tried to balance functionality, size and cost. As the Signal Controller (former Light Controller) is really small (6x34mm), and will easily fit into a car, I thought it was an acceptable compromise. You can also add more than one car controller to a car.

The current car controller has two light control outputs that can be used for various control functions such as brake lights, rear/brake lights, exhaust flames, glowing brake discs and safetycar flash lights.

The downside of adding more outputs are:
-The size of the car controller will be bigger than 15x22mm, and difficult to fit inside an F1 car.
-All the cars that don't need more than two light control functions, will be unneccesarily expensive because of added functionality they're not using.

Extreme example (slight exaggeration ahead) ... You have 20 ordinary cars and a Coca-cola truck
:
It would be cheaper to put a lot of light controllers in the truck, and keep the cost of the ordinary cars down.
 
#30 ·
Hi Gord
QUOTE (Newbie1/32 @ 2 May 2005, 10:48)One idea, if possible, would be having the option to wire the l/c's on there own circuit.Yes, its possible.

You will need an extra track controller, and then you'll need to wire the LC's separately instead of connecting tham to the track.
QUOTE Best of luck with your project
Thank you very much.
 
#32 ·
Hi Gord
QUOTE (Newbie1/32 @ 6 May 2005, 19:18)Sounds like you have thought about darn near everything to make a truely all around system
Thank you

QUOTE How is your prototype coming along?I'm currently working on the Track Controller. The CC seems to be ok, but I can't know for sure until I have the TC up and running. I'm starting out with a very basic system that will only allow you to control car speed and download new software. The plan is then to release a steady flow of software for download as new features are added.
QUOTE May I pry and ask when it will be available,and will it be more affordable to the general public than Davic?I can't really say for sure, but I'm hoping to have the basic system running before the summer holidays. The reason I can't be more specific is that there are many unknowns: how many problems will I meet?, how much spare time will I have?, will I have to redesign parts of the system?.

I'll keep you posted though when I'm closer to having a working system.

I've made a preliminary calculation of the component prices here ... look for the BOM.xls attachment to my post on 05.05.2005.
 
#35 · (Edited by Moderator)
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