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MEF Members and site visitors:
On many occasions, we hear mechanical noise in our circuits. This could stem from caps making funny noises, relays slamming open and close, or perhaps other inexplicable phenomena. And to help isolate a problem area, you either need to stick your head into a live circuit or use some other type of listening device.
I have seen and used home made Stethoscope type devices. This included small tubing - one end to poke around, the other in my ear. I have also used the inner tube of a paper towel role. Both help, but not a great solution.
So I did some research and found a cool project board (MK136) from Velleman - the folks that bring you inexpensive project boards. They sell a device called the "Super Stereo Ear." This is a project kit that uses two electret microphones that are amplified using the NE5532 audio amplifier. The cost was just shy of $13.
I made one mod to the kit - instead of mounting the microphones directly onto the pc board, I extended them so that I can have a safer "reach" area into a circuit board and other tight spots. I then twisted the wires and used heat shrink and hot glue to secure the connections.
Hey, this thing works! You can find some demo vids on YouTube. I am considering dropping this into a small project box. But "as-is" and knowing it will get used sparingly, it's fine the way it is. As I move into my elder years, I might even pack this thing in a front shirt pocket and use it as a poor man's hearing aid! Who knows, maybe I will super-extend the mics and have them hanging off my head like "Uncle Martin" (of "My Favorite Martian).
Tom
On many occasions, we hear mechanical noise in our circuits. This could stem from caps making funny noises, relays slamming open and close, or perhaps other inexplicable phenomena. And to help isolate a problem area, you either need to stick your head into a live circuit or use some other type of listening device.
I have seen and used home made Stethoscope type devices. This included small tubing - one end to poke around, the other in my ear. I have also used the inner tube of a paper towel role. Both help, but not a great solution.
So I did some research and found a cool project board (MK136) from Velleman - the folks that bring you inexpensive project boards. They sell a device called the "Super Stereo Ear." This is a project kit that uses two electret microphones that are amplified using the NE5532 audio amplifier. The cost was just shy of $13.
I made one mod to the kit - instead of mounting the microphones directly onto the pc board, I extended them so that I can have a safer "reach" area into a circuit board and other tight spots. I then twisted the wires and used heat shrink and hot glue to secure the connections.
Hey, this thing works! You can find some demo vids on YouTube. I am considering dropping this into a small project box. But "as-is" and knowing it will get used sparingly, it's fine the way it is. As I move into my elder years, I might even pack this thing in a front shirt pocket and use it as a poor man's hearing aid! Who knows, maybe I will super-extend the mics and have them hanging off my head like "Uncle Martin" (of "My Favorite Martian).
Tom
Attached Files
But this would (of course) mean the cap is taking the brunt of whatever anomaly is causing the noise. I suppose mechanical circumstances could happen in that case.
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