1/ 100th second Slot car Timer


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  1. #1
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    Default 1/ 100th second Slot car Timer

    I am trying to build a timer for my slot car track with VB and a pic. I am using a pic 16f84a but can also use the 877 for more I/O ports. My question is this ..
    Can the 9800 baud (whatever) serial com port handle a 1000th of a SECOND input or will it crap out under the speed it takes to get the signal and process it into the monitor. I could just trigger the built in timer for VB but as we all know it is not the most accurate of controlls. I want the Pic to tell the PC the elasped time in real time. I might be able to use get time option in VB but I want to use the PIC. Once I get the signal into VB I can generate charts., graphs whatever I just need to know should I be trying to solve this in pic basic and send the info to VB or vice versa....
    Any suggestions (There are no wrong answers)
    Beer is proof that God loves us and wants us to be happy.

  2. #2
    skimask's Avatar
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    Quote Originally Posted by Snap View Post
    I am trying to build a timer for my slot car track with VB and a pic. I am using a pic 16f84a but can also use the 877 for more I/O ports. My question is this ..
    Can the 9800 baud (whatever) serial com port handle a 1000th of a SECOND input or will it crap out under the speed it takes to get the signal and process it into the monitor. I could just trigger the built in timer for VB but as we all know it is not the most accurate of controlls. I want the Pic to tell the PC the elasped time in real time. I might be able to use get time option in VB but I want to use the PIC. Once I get the signal into VB I can generate charts., graphs whatever I just need to know should I be trying to solve this in pic basic and send the info to VB or vice versa....
    Any suggestions (There are no wrong answers)
    9600 baud = 9,600 bits per second. One byte = 8 bits, plus one start bit, plus one stop bit = 10 bits total, plus an extra bit time for a space between bytes = 11 bits....
    9,600 = 11 = 872.72 bytes per second = .00114583 seconds per byte.
    Can the PIC handle the speed? Sure, the PIC can handle a lot of speed. But, as you can see, at 9600 baud, each byte takes more than 1/1000 of a second to transmit. So, if you have 2 cars hit the trap at the same time, and your max resolution is actually 1/1000 second, the second message might get missed.

  3. #3
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    Thank you for your answer I see I have a lot more work to do before I hammer out the details. I will post this when I get it going. As always I can't believe the speed and quality of help in this forum. Thanks again
    Snap
    Beer is proof that God loves us and wants us to be happy.

  4. #4
    skimask's Avatar
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    Quote Originally Posted by Snap View Post
    Thank you for your answer I see I have a lot more work to do before I hammer out the details. I will post this when I get it going. As always I can't believe the speed and quality of help in this forum. Thanks again
    Snap
    You know, with a PIC, an LCD, a couple of push buttons, and a few IR LEDs and IR detectors, you can easily make a slot car track timer and wouldn't even need a PC. There's probably enough on chip eeprom to store several races (if that's one of your goals), then you could download the data to a PC later on thru a serial port.

  5. #5
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    Do a search on the forum for Olympic Timer.

  6. #6
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    I did download your program and greatly apreciate the code but I would like to have it on the PC so I can show it on a projector and play with things like sound and pictures as well as generate an excel spread sheet. I have set up the light tripping start and got it working great I just have to do the homework and see how I can feed information to the PC and have it update every 1/100 th of a second. I will post the code for both when I get it right.
    Thanks
    Snap
    Beer is proof that God loves us and wants us to be happy.

  7. #7
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    Talking Sorry, I was misled by the positive results

    I have finally finished my slot car timer, I had to totally scrap my pot the cad pin programming because it took to darm long. the better way was to use the IR beam break tecnology and use that for my signals. The biggest problem turnrd out to be DC EMI of spikes caused by the car motors. I fixed that in the programming E-mail me if you are designing a simular project and I will help as best I can. Thanks to the forum for all the help.
    Snap
    Beer is proof that God loves us and wants us to be happy.

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