Hi,
I'm trying to use a piezoelectric transducer to trigger a relay, to turn on regular house current. I am using an lm324 opamp to keep the signal positive, and was trying to use a 555 in one-shot mode to lengthen the burst from ~20ms to ~100ms.
However, it looks like the trigger for the 555 is a switch not a voltage pulse. I believe I would need to use a transistor as a switch here, but i really dont know enough to be able to choose what kind of transistor or even how to set it up.
The 555 monostable circuit:
**broken link removed**
(this image is nearly identical to example circuits in 555 manufacturer pdfs)
The output from the lm324 opamp is about 7v, and about 20ms long, but it is not a square pulse at all.
Any help would be great. I'm a software guy, but trying to learn the better side of things here.
Thanks,
ffuzz
I'm trying to use a piezoelectric transducer to trigger a relay, to turn on regular house current. I am using an lm324 opamp to keep the signal positive, and was trying to use a 555 in one-shot mode to lengthen the burst from ~20ms to ~100ms.
However, it looks like the trigger for the 555 is a switch not a voltage pulse. I believe I would need to use a transistor as a switch here, but i really dont know enough to be able to choose what kind of transistor or even how to set it up.
The 555 monostable circuit:
**broken link removed**
(this image is nearly identical to example circuits in 555 manufacturer pdfs)
The output from the lm324 opamp is about 7v, and about 20ms long, but it is not a square pulse at all.
Any help would be great. I'm a software guy, but trying to learn the better side of things here.
Thanks,
ffuzz