Car door open alert

tracecom

Joined Apr 16, 2010
3,944
I think that sound is too complex to be produced by a 555. You will likely need a real audio file (such as an MP3 file) put on one of those audio greeting card chips.
 

LDC3

Joined Apr 27, 2013
924
You might get something close with a 555 timer since it is just one pitch, but I think it is a combination of tones, which would need more 555s. Also, you need a sawtooth generator to control the volume (which needs another 555).
 

LDC3

Joined Apr 27, 2013
924
Here is the schematic I came up with which you will need to do some adjustments to for the right tone. The 556 timer is used to produced 2 tones which you can vary by changing R2 and R4. I just realized that C5 should be 1 μF and not 0.1 pF. R6 will vary the length of time the volume decreases over. R8 and R9 should be the same as R2 and R4. This will change the square wave to a sawtooth wave with nearly equal rise and fall times. R10 will control the volume as well as the feedback amplification of R15 and R16.
 

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vivc

Joined May 27, 2013
2
Here is the schematic I came up with which you will need to do some adjustments to for the right tone. The 556 timer is used to produced 2 tones which you can vary by changing R2 and R4. I just realized that C5 should be 1 μF and not 0.1 pF. R6 will vary the length of time the volume decreases over. R8 and R9 should be the same as R2 and R4. This will change the square wave to a sawtooth wave with nearly equal rise and fall times. R10 will control the volume as well as the feedback amplification of R15 and R16.
This looks interesting. I'll give it a try & let you know!

Cheers!
 
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