The next metal detector THE BLIND SQUIRREL

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The next metal detector THE BLIND SQUIRREL

Postby Harry Dalek » Tue Jan 14, 2014 6:57 pm

My first pulse induction metal detector works and i am casing up and just working out the coil housing , my thoughts are going to mark 2 .

I am making more as i have a few kids and daddy wants hes own !

What i want on the second one is a more simple power supply for a start !

Looking at a few versions of a Pulse induction type of detector again most were modified versions of the hammer head Pi so all have dual power supplies at best .

I came across this site
http://oldradiobuilder.com/mdetsp.html
and had the main schematic below which i liked but the ic's are hard to get .
I came across a forum some one had the idea to change the parts of that design and see if they could make a simple as possible pulse induction type .

Why i am posting the schematics up is i want to use a 4528 monostable instead of the 4538 as far as i can see they are pin for pin the same ?

i have a TL072 as a replacement for the 71 just i have one handy the 72 is a dual opamp i think the 71 is a single of the same family.

Also i am not sure about the last version in that the circuit for the TL071 is simplified .

Just running it past any one that wants to have a look and may pick up any problems on any of those circuits .

As far as i can see most of it makes sense .
Attachments
original.png
Heres the original circuit
original.png (103.52 KiB) Viewed 2308 times
concept1.jpg
Heres the Modified version1
concept1.jpg (88.87 KiB) Viewed 2308 times
concept2.jpg
simplified version
concept2.jpg (93.79 KiB) Viewed 2308 times
blind S.jpg
BLIND SQUIRREL ; )
blind S.jpg (8.38 KiB) Viewed 2306 times
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Harry Dalek
"Fester! Don't do that to 'Thing'"
 
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