Bill of Materials

These are the components you will need in order to use Race Coordinator timing software with Arduino hardware. The links and prices given are from Jaycar Electronics and are generally available in Canberra. These components can be purchased elsewhere, such as eBay, which will be cheaper, but will take longer to be shipped.

Component	Quantity	Details	Approximate Cost
5v Power Supply	1	Use an old phone charger	$0.00
56Ω Resistor	1 per lane	56 Ohm 0.5 Watt Metal Film Resistors	$0.85 for a pack of 8
Arduino	1	Duinotech UNO r3 Development Board	$29.95
Arduino Connector	1	40 Pin Header Terminal Strip	$1.10
Call Button	1 - many	Small Black SPST N/O Momentary Action	$3.95 ea
Call Button Cable	1-2m per call button	Light Duty Fig 8 Speaker Cable	$0.70 per metre
Lap Sensors	1 per lane	Infrared Phototransistor	$1.75 ea
Light Bridge LEDs	1 per lane	White 5mm LED 33000mcd Round Clear	$2.75 ea
Power Cut Relays (optional)	1	4 Channel Relay Shield Module for Arduino	$14.30
Sensor and Light Bridge Cable	2-5m	Cat 5e Solid Core Network Cable	$1.20 per metre

Wiring it up

The below wiring diagrams shows a simplified view of how the timing system should be wired up if you are not using power cut relays.

Standard Arduino Wiring

Power Cut Arduino Wiring

Notes

• The light bridge LEDs and lap sensors will be damaged if they are wired backwards, take note of which wire shold connect to which leg.
• The light bridge LEDs and lap sensor legs can be distinguished by their length.
• It is best to connect the 56Ω resistors directly to the light bridge LEDs.
• Do not get the light bridge LEDs and lap sensors mixed up, they look the same but function very differently.
• Where the colored lines cross other lines, they are not to be connected together.
• If you have multiple call buttons, they are wired in parallel to the call button on the diagram, ie the black wire connects to one pin and the brown wire connects to the other.
• You do not have to use the specific coloured wires shown in the diagram, the colours shown are just an example.

CARRACE uses Race Coordinator for computer timing. Race Coordinator is a free alternative slot car lap counting software package for the PC. It is highly featured and does everything we need for computer timing.

If you like Race Coordinator and use it regularly, please consider donating to Dave, the Race Coordinator developer, or supporting his nominated charity. Click here for more information

Race Coordinator can be downloaded here.

To configure Race Coordinator to use the Arduino timing system:

1. Launch Race Coordinator, then click the Track Setup menu and select Expert Track Setup.
2. On the General tab, enter your track name.
3. Switch to the Lanes tab, configure lanes and colours for your track, then click the Update > > button.
4. Switch back to the General tab. Under Track Interface heading, click Arduino, then click Configure.
5. In the Manage Arduino window on the General tab, select the COM port the Arduino is connected to, yes it is connected to USB and not a COM port, but this is the way the Arduino presents itself. The COM port will differ from computer to computer, but is usually the highest numbered COM port.
6. Switch to the Analog Setup tab, then set all the pins to Unused.
7. Switch to the Digital Setup tab and set the following:

   Pin 5 (If using Power Cut relays)	Relay: L3
   Pin 6 (If using Power Cut relays)	Relay: L2
   Pin 7 (If using Power Cut relays)	Relay: L1
   Pin 8	Lap L1
   Pin 9	Lap L2
   Pin 10	Lap L3
   Pin 13	Callbutton
   Remaining Pins	Unused

   
8. Click Accept.
9. Back on the Track Manager window, click the Update > > button to save your Arduino configuration.

All of the CARRACE tracks use positive polarity wiring, this means that it is the positive rail that the controller varies when the trigger is moved. Most controllers are electronic controllers, which are polarised, i.e., you must use a positive polarity controller on a positive polarity track.

Bill of Materials

These are the components you will need in order to wire up the power for your track. The links and prices given are mostly from Jaycar Electronics and are generally available in Canberra. These components can be purchased elsewhere, such as eBay, which will be cheaper, but will take longer to be shipped.

Component	Quantity	Details	Approximate Cost
Controller Sockets	1 per lane	Clipsal 412/110 Single Socket Outlet	$35.50 ea
Direction Switch (optional)	1 per lane	DPDT 6A 240VAC Heavy Duty Centre Off Standard Toggle Switch	$5.95 ea
Variable Power Supply	1	Compact Switchmode Laboratory Power Supply or HOP WO INT-1288 Power Supply 5-15VDC (0-15 amps adjustable)	$169.00 $79.00
Wire	2-3m per lane	Red Heavy Duty Hook-up Wire Black Heavy Duty Hook-up Wire	$0.65 per metre $0.65 per metre

Positive Track Wiring

This diagram shows the simplest track wiring that is possible, it will only have one direction of travel and no power cut capability.

Positive Track Wiring with Direction Switches

This diagram adds direction switches to the track wiring, allowing you to run your track in both directions.

Positive Track Wiring with Power Cut Relays

This diagram adds power cut relays to the track wiring, allowing the timing software to stop the cars. Your track will only have one direction of travel.

The optional wiring in this diagram will give the cars full brakes when the power is cut.

Positive Track Wiring with Direction Switches and Power Cut Relays

This diagram adds direction switches and power cut relays, allowing you to run your track in both directions, and allowing the timing software to stop the cars.

The optional wiring in this diagram will give the cars full brakes when the power is cut.