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Help with Using a 555 Timer Chip as a Pulse Extender — Parallax Forums

Help with Using a 555 Timer Chip as a Pulse Extender

cljennacljenna Posts: 10
edited 2006-06-21 19:27 in BASIC Stamp
I am using the Board of Education to input a signal coming out of a CCD camera and synchronize the camera with the output device, which is a beam shutter (used with a laser). The problem is that the camera's output signal is normally high, but goes low every 1/30 s for approximately 1/500 s. The Board of Education is programmed to detect this "low" and then execute the code. After modifying the code to be as efficient as possible, it seems that the low signal is too short for the Board to assimilate. I was told by Parallax Tech Support that a 555 timer chip could help extend this pulse so that it would actually trigger my loop. I was wondering if someone could help me out with where the chip needs to go and how it should be wired. I currently have a NPN·transistor and·1K resistor·on the board used to trigger the beam shutter. Any help would be greatly appreciated. Thanks!

Comments

  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-06-21 19:27
    OK -- most all of the datasheets of the 555 (and variants) include examples of the standard circuits: monostable and astable.· You want a monostable circuit (also known as a "one shot.")
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