DC-Car
How does the digital control work?

All you need for digital control of a vehicle fitted with a DC-CAR decoder, is a DCC Controller or a function module and several infrared transmitters.

Control with a DCC Controller

There are two ways to control vehicles with a DCC controller:

1. With strong infrared transmitters covering the entire road system

Since the sensitivity of the receiver in the vehicles is limited, in order to suppress external influences such as neon lamps etc., several infrared LEDS must be combined into a transmitter. Several of these transmitters need to be installed above the layout.

2.With weak infrared transmitters installed at places on the layout where you wish to control vehicles.

SMD format transmitters can be located nearly invisibly in/under parked cars, curbs, guard rails, sign posts, mail boxes, dustbins etc..

Using 3mm or 5mm diameter LEDs

The resistors shown are suitable for use with 3mm/5mm infrared LEDS. The diagram shows two variants of the transmitter:
1. The connection of infrared an LED with a 220 - 1k ohm resistor
2. The series connection of 6 infrared LED with a 47 - 1k ohm resistor

The longer lead of the infrared LED is the positive (+) connection.

Using SMD (Surface-Mount) LEDs

The resistors shown are suitable for SMD infrared LEDs size 0603/0805.

The diagram shows two variants of the transmitter:
1. The connection of a SMD infrared LED with a 680 - 2K2 Ohm resistor
2. The series connection of 6 SMD infrared LED with a 150 - 2K2 Ohm resistor

With SMD LEDS you need to check the markings to establish the correct polarity.

Notes on LEDs

The longer lead of the infrared LED is positive (+) connection. With SMD LEDS you need to check the markings to establish the correct polarity.

In order to avoid destruction of the infrared LEDs, a 1N4001 diode must be used.

With the smallest resistors shown the range of the transmitters shown above will be at most 50 cm.
The range of the transmitters can be adjusted by changing the value of the resistor.
The smaller the distance between the transmitter and the vehicles, the larger the resistor can be.
In addition, individual transmitters can have different ranges. If an individual transmitter only needs a range of approx. 10 cm, then the resistor for an individual LED could be increased to 1K Ohm.

The transmitters are attached to the track connection of the DCC controller or DCC booster.
Thus you can control trains and cars at the same time.
Make sure that your locomotives and cars do not use the same DCC addresses.

Note:
The transmitter connected to the DCC controller can affect the ABS system if it is too powerful. It is better to use several weaker transmitters. My recommendation is to use weak transmitters where vehicles eed to be controlled.

Using DC-Car with a DCC Controller

The vehicles store the instructions they receive, and implement them even if they are out of range of the transmitter.

All DCC commands are transmitted. Each vehicle will react to its own address.

Once the transmitters are attached, switch the DCC controller on.
Enter the digital address of the vehicle on the controller, as you would a locomotive.
If necessary on your DCC controller select 28 speed steps for this address.

The following functions are supported by the DC-CAR decoder:

• Speed
• Turn signal - right
• Turn signal - left
• Hazard flashers
• Headlight
• Blue light
• Front flashing lights
• Two extra outputs (light 2 and light 3)

Switch the vehicle on and place it on the road.
If it has visual contact to a transmitter, it will probably stop, because the DCC controller will send speed step 0.
Increase the speed to, say, 10.
The vehicle should now drive off.
Set to speed step 0. The vehicle will stop again.
The decoder does not recognise ‘reverse’.

The DCC controller’s function keys operate as follows:

• F0 switches the headlight on or off
• F1 switches the left hand turn signals on or off
• F2 switches the right hand turn signals on or off
• F1 and F2 together switch the hazard warning flashers on or off
• F3 switches the ABS on or off
• F4 enables or disables the reed switch for magnetically stopping the vehicles (if fitted)
• F5 switches the blue light on or off
• F6 switches the front flashing lights on or off
• F7 switches light 2 on or off
• F8 switches light 3 on or off

Note:
With some DCC controllers functions F5-F8 will only be actioned if the vehicle is within range of a transmitter when the key is pressed.
Whilst a car is using ABS to follow another vehicle or respond to a function control it will not accept speed changes from the DCC controller. All other functions will still work.
More information can be found in the section on Driving using a DCC controller.

Control with function modules

With these modules you can control vehicles without a DCC controller.
Each module has eight outputs for infrared LEDS to switch functions on the vehicles.
Each individual transmitter is installed by the road where a certain function is to be switched.
See the section on Driving using DC-Car function modules.

Future plans/development

• Feedback of the battery level to the DCC controller or for switching a junction, so that a vehicle can automatically drive into a battery charging area.
• An inexpensive infrared booster.

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Disclaimer:
This page has been translated, with permission, from a page on Claus Ilchmann’s web site.
The original page, in German, is located here.
This translation is provided with no guarantee of accuracy or liability for errors.
Should you decide to use the DC-Car system then you should check that the functionality meets your needs by reference to the manufacturer’s web site.