Collecting Design Requirements Remote Radio Stethoscope

[Daless2]

Collecting Design Requirements Remote Radio Stethoscope

Hi Folks, I want to build something that I think will be useful for many of us; A remote, radio transmitter stethoscope to be used when trying to diagnose where a sound is coming from under a vehicle.

The idea is to strap this little transmitter (2? cube) to an under body component using a velcro strap.

You would then tune your FM radio to the transmitting frequency and drive away listening for the sound on the Jeeps radio.

It may take placing the transmitter in a few different spots, but I do believe it would work to get down to the component that is causing the noise.

You folks want to give me your input on this?

Here are my design requirements so far:

• Small, target is a 2-inch cube.
  Easily reproduced circuit using minimal parts. (If you can solder you can build.)
  9-volt battery for power.
  Able to receive stethoscope signal on Jeeps FM radio (87.9 or something like that.)
  Able to easily mount on any non-moving under jeep assembly.
  Somewhat watertight, if not waterproof.
  Under $10 in cost.

I have a fiend, Chris B who is a new Jeeper from near Cleveland, Ohio. (I have also invited him to join this forum.)

Chris is not only an Electrical Engineer, but he is one of those really smart ones too! He makes his living designing chips that control CT/CAT scan machines.

Once I collect your thoughts on how this thing should function and what features it should have I am going to enlist Chris?s help in designing the remote stethoscope.

Please share your thoughts.

Frank

[mrblaine]

First off, does your friend know you think of him as a fiend? What sort of fiend is he?


I often have need of a device such as this. Would make my life much easier diagnosing some stuff.

I think you pretty much have the requirements nailed down. Let us know how it goes.

[Daless2]

Originally posted by mrblaine
First off, does your friend know you think of him as a fiend? What sort of fiend is he?

Well Blaine, that just goes to show you, I can get in trouble even when I run something through spell checker first!

What's even more amazing is I had to read your post 4 times before I got it!

I had another thought on this little unit I want to design and build.

If it can be built cheap enough, then why not have four or five of them, all transmitting on slightly different frequencies like

87.1, 87.3. 87.5 ect.

Then they could all be velcro'd in different places under the Jeep and you would just tune the radio to find the unit closest to the noise.

Chris and I will get one working and take it from there. First unit after that will be coming your way for evaluation Blaine.

Thanks for getting me laugh at myself!

Frank

[Daless2]

For some reason Dan is unable to post to this thread. He sent me his comments via PM so I will cut and paste them on the thread.

Here are Dan-H's thoughts.

"Frank,

for some reason the BB won't let me post in your thread on the stethoscope:???: If you want you can copy this into the thread.

Here are my rambling thoughts.

how will the microphone work? will it be protected from wind noise? Will it pickup noises transmitted via vibration into it or will it just listen for noises.

I'm interested in trying one but I'm curious how it would filter out other noises like exhaust noise, engine noise and wind noise.

I'd be happy to test one for you since I have an annoying squeak somewhere on my rear axle when going over speed bumps at about 10-15 mph.

Also, will the transmitter clip to the antenna? or will it have enough power to broadcast. Is a license needed for this? If so, what about FRS frequencies. Then a set of head phones and this could make it useable anywhere.

Thanks for sharing the idea.

- Dan"