Speed Climbing Timing - Part 3 Integration
02/21/2009 19:39
Synopsis: This is a video to show the initial integration of the IR sensors with the stop switch interrupt of the microcontroller. There’s more work to do as you will see. Later in the article are a couple videos which show the system working after an EMI issue caused spurious interrupts.
The basic integration of the IR sensors with the AVR is:
Video below the break....
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The basic integration of the IR sensors with the AVR is:
- IR Sensors have a high frequency component and the overall wave goes from about .8v to 2.5-3V.
- I take the IR signal into a low-pass filter to clean up the signal and remove the high frequency components
- That signal goes through a non-inverting comparator and amps the signal to the rail when the IR beam is reflected with a hand
- The output of the comparator goes to a hex inverter (74LS14) schmitt trigger
- The output of the schmitt trigger goes to the interrupt of the ATMega128.
Video below the break....
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Speed Climbing Timing - Part 2 Controller
02/19/2009 17:04
In Speed Climbing Timing Part 1, I introduced the touchless sensor concepts of a speed climbing timing system. In this part, I’ll demonstrate the basic controller and the timing functions as well as the display driver.
The display is based on a Maxim 7219 LED multiplexor. The controller is an Atmel AVR ATMega128. I’ve developed the Max7219 driver code and the basic timer to deal with a two-lane speed climber competition.
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The display is based on a Maxim 7219 LED multiplexor. The controller is an Atmel AVR ATMega128. I’ve developed the Max7219 driver code and the basic timer to deal with a two-lane speed climber competition.
Read More...
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