| Author | Message | ||
     Paul Timmermann |
Your past message about timing devices said the video camera idea which measures 1/30 of a second unfortunatly that is not quick enough. I at least need to measure hundreths of a second or even better thousandths. Do you know anyway to measure even more exact than the video camera. | ||
| Simon Quellen Field (Sfield) |
It's easy. Use a strobe. You can make one from an integrated circuit timer chip such as the 7555 and a bright LED. Then take a picture. The images in the picture will be as far apart in time as the flashes were. If you use a 1 Mhz crystal oscillator, and divide the counts down with a divider integrated circuit, you can get very accurate divisions of a second (down to single microseconds). | ||
| Paul |
I am the person who has written Timing Device and Timing Device II. I don't think I was a clear as I should have been. I am not racing cars against each other. I am just running them singlely for elapsed time. If you could help me once again to figure out a way to time a car in hundredths or thousandths of a second from when it starts to where it finishes (which is 45 feet). | ||
| Simon Quellen Field (Sfield) |
A phototransistor can be placed between Ground and Data Set Ready pins on a serial port. An LED illuminates the phototransistor. When a car breaks the beam, the computer notices (the line state changes). The computer is running high resolution clocks (100 nanosecond resolution). You can place a sensor at the start and end of the race, and have the computer do the timing. Using the Carrier Detect and Clear To Send inputs along with the Data Set Ready input, you can time three events per serial port. There are other input signals available on serial lines, but not all systems allow you easy access to them. | ||
| Paul |
I really like your idea and it seems very useful to me so I hate to send things back and forth forever. If you would please post or send me a "grocery list" of what I need to build the timer and if possible tell me where I could get stuff on the list, I would greatly appreciate it. (P.S. You are by far going on my list of people who helped me in my experiment.) |
