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Slot car tv cronograph
This design is based on the video DVM design. Furthermore, it adds support for color, so you will get red and green semaphore lights (as those in formula 1) and sound: you will even hear the starting-horn sound!
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Up to 3 times are displayed on YOUR TV screen. When you press the START button, the red semaphores will light on, and, after a random delay, the unit activates the green ones emitting a bleep sound. If one of the runners starts in advance, a jump start (F= false start) indicator is displayed. |
Timers increment with 1/100 resolution until last lap, when they are stopped by the photocells. Maximum race time is 99".99. Even chekerboard flags will appear near the times when each runner comes to end! At the race end, times are transmitted through the serial interface as ASCII strings at 1200 baud. Altough, computer is NOT necessary as the same information is displayed on TV screen.
All is done using only a 512 lines assembler program, showing well the compactness of the Atmel's AVR AT90S1200 code.
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"START" fires the red semaphores. Random time, then lights turns to green and time runs. Here the 3rd car made a jump start, making the race void. |
Time runs. The arrows mean "other laps" to end. Photocells are inhibited until the judge presses the "LAST LAP" key. |
As cars reach the
finish line, time stops and the checkerboard flag appear. |
Times are triggered by photocells, that can be replaced by any other mechanical or electronic switch, so you can time any other short event (up to three timers at once).
Files available:
view or download .gif schematic
download sources, eeprom image, flash image as one .zip file
For additional information don't forget to check the FAQ page.