| Author | Message | ||
     Monopix Tinkerer Username: Monopix Post Number: 112 Registered: 11-2008 Rating: N/A |
"you really might want to consider a design more like mine" The display was supposed to be able to count much faster than it actually could which is why I ended up with the clock speed I did. A Xtal clock would be more accurate and I still intend to change it at some point but I actually don't use it that often and it's easy to trim the clock prior to each use so it will be almost as accurate. I don't see the need to do anything more complex so I don't see the point of designing from scratch if you can buy an off the shelf module that does all the counting and display for you. Having said that, I would like to find one that's capable of counting at at least 100KHz. Probably the most important thing though is the understanding that the width of the beam needs to be very small to be able to measure fast speeds with any sort of accuracy. If you don't sort that problem, no system, however it's constructed, will be accurate. Just to complicate things further, I also think a tester really needs to be capable of measuring the speed at different points of the shutter travel to be able to check for tapering or capping. Using mine as I do, with the camera on a tripod, the laser on a support in front of the camera and the tester sat on a table behind the camera, I can move the camera around freely to align the setup with different parts of the shutter. That's been of real benefit in the past. |