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A Half Round Dish would be good, ONLY IF it Were a Real Parabolic Shape.
Just being a Bowl shape, Doesn't mean it directs much sound to the mic.
A true parabolic is Quite Useful and will direct all sound to the mic.
And just put a Cup around your mic, to help prevent pickup from the sides.
I have a lot of experience with this and made Many of these devices.
I would like to see a common household bowl cook a hot dog using the sun's energy.
BUT have a switch that can turn the volume WAY DOWN for using a headphone
I need to investigate the 2n5088 and 2n5087 transistors. maybe sub using 2n2222 2n3906?
There is a definitive math formula for the parabolic curve as used in a sat dish.
No I was thinkingh of 7 watts so I could use a speaker instead of a headphone
To blow the eardrums out!! LOL
No I was thinkingh of 7 watts so I could use a speaker instead of a headphone then more boys could hear what the BIG EAR is picking up instead of one at a time PLUS I have 5 on hand (L4950TA).
BUT have a switch that can turn the volume WAY DOWN for using a headphone ( a switch so a preset volume is used, someone can't be "funny" and turn up the volume.
have a dip switch combolock to control the volume.
remember we as adults have to be smarter than the kids.
you never know what kids will do. be perpared for anything.
I need to investigate the 2n5088 and 2n5087 transistors. maybe sub using 2n2222
2n3906?
I have a big ear listening device that I built using 2 LM386 ICs 32 years ago. I can hear people over a mile away talking and it sounds like they are standing right next to me. As I recall the LM386 have an amplification of 200 so 2 in series is 200 x 200 = 40,000. You need a volume control on the first stage so it will not over drive the second stage. You need to couple the output of 1st stage to the 2nd stage with a capacitor. Mine runs on a 9 volt battery but 12 volts works much better. I a using a cheap quality 8" speaker as the microphone, point it in the direction you want the listen it acts like a dish and pics up sounds like you won't beleive. This is an extremely simple device to build it only requires a few parts to make the ICs work.
If you want the circuit drawing I think I still have it but it might take me a day or so to find it. If not I can probably draw a new circuit from my circuit board that I etched with all the parts soldered to it.
An 8 Inch Speaker as the Mic? Pretty Poor Impedance Matching to the LM386 Input!
And Definately VERY LITTLE Directional Ability!
The speaker is connected to the circuit with a tiny little speaker transformer hooked up backwards. Perfect Impedance Matching. No one uses speaker transformers anymore so this may be the hardest part to find for this circuit all the rest of the parts are common. Remember back in the stone age when speakers used a impedance matching transformer? Maybe your not from the stone age?
Also, the Frequency Response of an 8 inch speaker is Pretty Limited.
A parabolic microphone is limited to higher frequencys anyway.
A parabolic microphone is limited to higher frequencys anyway.
At 6 feet in diameter ya maybe, but try and get good bass out of one using a 18" SAT dish.I have a 6 Foot Diameter Parabolic and it also gets Considerable Bass Response
Ummm... Ya! look it up. The wavelength of low frequencys is so long a small dish will not pick them up. AndyUmmmm ... no.
Ummm... Ya! look it up. The wavelength of low frequencys is so long a small dish will not pick them up. Andy
Actually those tiny transformers are Still QUITE READLY AVAILABLE.
("Mouser", 42TL Series of transformers.)
But as I said, Your Speaker will pick up in All Direction, Unless it is put into a Parabolic Dish.
Also, the Frequency Response of an 8 inch speaker is Pretty Limited.
A Tiny Transistor Radio Speaker (if 2 or 3 Inches) would be somewhat better.