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Start sequence to race, then show winner for Hot Wheels type cars. Displays total race time, both car speeds and winning difference in ms.

My Hot Wheels Race Start and Finish Line Timer project is designed to show the winning car in a 2-car race contained in a child-friendly, easily transportable self-contained case that is less than 13x10x12cm. Simply place the unit over the tracks and connect a USB power supply. No additional set up is needed. The race timer starts with a grand prix style audible start sound and flashing light sequence. Once the lights go out, the race starts and the time is measured. As the first car passes the sensors, the winning car’s lane LED is immediately turned on providing instant visual confirmation of the winner. Once the second car finishes, the winning race time and time difference (in 1/1000 of a second) between the winning and losing car is displayed on the onboard LCD . After a short delay, the individual car’s actual speed it travelled through the gate is shown (Km/h), followed by the scale speed of each car (based on Hot Wheels scale of 1:64). The timer then resets for another race with the race start sound and lights sequence. If the second car does not pass the sensors within 10s of the first car passing the sensors, a crash is assumed and the winning lanes times and speeds are displayed before resetting for another race. The theoretical maximum speed the unit can measure is 144Km/h with a time accuracy of +/- 2ms (based on Arduino Uno hardware).

Data can be transmitted to a computer via the USB serial interface to reveal more detailed information, including actual times in milliseconds. This could be used as a record in a Grand Prix style event or for comparing different cars characteristics.

The software can be quickly changed to a debugging mode by simply changing some of the CONST flags at the start of the code. Changing the value of COMP_OUTPUT improves the speed of simultaneous sensor detection of the unit by not outputting data to a computer. Setting the DEBUG flag provides the output of detailed debugging information, such as sensor readings, via the USB serial link. These will prove invaluable in setting up the unit for your individual software. Furthermore, the use of complier #if statements means that unwanted code is not compiled and uploaded to the Arduino. This reduces program space required and improves the execution speed of the program to further improve accuracy.

Further development of the software has resulted in a dual function unit additionally capable of continuously displaying and recording the speed of cars passing the sensors or the race start/finish timer mode as above. Watch the videos for more information. You can purchase a How to Guide and the additional software to make this hardware into a dual function Race Timer and Speed Measurer at:

This add on product includes a workbook with full design detail on how to make the project, including parts list, circuit diagram, technical drawings of the casing with dimensions and the software for the dual function unit.”

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