I'm working at a project to open gates automatically. When I was about designing an alarm circuit to indicate emergency power cut-off in case the gate is jammed I got the idea that a sweeped tone won't be overheared easily.
I found chips for telephone ringers, but they are single tone only. (The same can be done making a gated oscillator circuit using a CD4093).
You can make either of the warble or sweep oscillators using 2 gates of your cd4093. Set 1 gate up for the high frequency (carrier) and 1 gate for the low freq (modulator) oscillator. Connect the inputs of 1 oscillator to the other using a resistor, this will modulate the frequency of the high frequency osc.
The resistor connecting the 2 oscillators should have a higher value than the feedback resistors on each oscillator.
You can make either of the warble or sweep oscillators using 2 gates of your cd4093. Set 1 gate up for the high frequency (carrier) and 1 gate for the low freq (modulator) oscillator. Connect the inputs of 1 oscillator to the other using a resistor, this will modulate the frequency of the high frequency osc.
The resistor connecting the 2 oscillators should have a higher value than the feedback resistors on each oscillator.
You could instead use 2 555s or a 556 to produce the 2 oscillators. The output of the low freq one is fed through an RC into the control input of the high freq one. This also works and is not ugly.
Radioshack used to have a horrible-sounding people detector at its entrance/exit. It produce square-waves like electric guitar fuzz and did not sound like a smooth chime. It was DING-DONG!
Radioshack used to have a horrible-sounding people detector at its entrance/exit. It produce square-waves like electric guitar fuzz and did not sound like a smooth chime. It was DING-DONG!
You could also get one of the DTMF generator chips. They produce sine wave output, without the buzz. If you press two keys, you get a single frequency (rather than the usual two frequency mix), from which several different tones can be generated. You can alternate between them for warble. Simple. No chirp, though.
With the latest schematic I posted there is a problem. Whenever the trigger output of timer1 is connected to the control voltage pin of timer2, timer1 quits oscillating.
Arnt warning alarms by design supposed to be annoying and unpleasant to the ear?
Its what makes you take notice and correct the problem!
If industrial equipment back up alarms played your favorite song in 7.1 suround sound at the perfect volume would you still jump out of the way so quikely?
If industrial equipment back up alarms played your favorite song in 7.1 suround sound at the perfect volume would you still jump out of the way so quikely?
Hi, Boncuk,
I've just joined on here "Hi" are those People detectors, still available? if so where can I get one please.?
And did you mange to get your sweep Generator completed?
cheers
vortex2009