Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

555 timer metal detector

Status
Not open for further replies.
H

human304

Newbie level 6
Newbie level 6
Joined
Jul 30, 2012
Messages
12
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,358
Hello everyone. I am designing a simple metal detector using the 555 timer. This is the link:
https://www.555-timer-circuits.com/metal-detector.html
Capture.JPG

However the sensitivity is very poor. How can i increase the sensitivity of the detector.
 
Last edited:

Instead of a 10 mH coil, use a larger flat coil, like 50 turns of 0.5 mm dia.wire would on at least 6" diameter, in a tight strain. Detecting metals requires to affect the coil inductance by a larger metal mass. Using a small coil might only detect a magnet if it affects coil iron core.
Better metal detectors use larger coils, also the beat-frequency principle for a good sensitivity.
 
Thank you for your reply. can you please give me some details on how to implement the BFO principle using 555 timer.
 

Is there any way of increasing the efficient distance sensing without increasing
the diameter of the coil? I tried various things, such as increasing the induction to 100mH
and different caps with no success.
Amitai
 

amitaiwe said:
Is there any way of increasing the efficient distance sensing without increasing
the diameter of the coil? I tried various things, such as increasing the induction to 100mH
and different caps with no success.
Amitai
Click to expand...

In a metal detector, a flat large coil is preferred as its magnetic field is spread over a wider area. A small coil can help to detect close objects only.
I would suggest you to google metal detectors and see how it is done.
The beat-frequency method uses two or more coils overlapping, and adjusted so that the beat from two oscillators feeding two coils is rejected like in a bridge system. Then presence of a metal object mis-balances the system and the beat frequency is heard. This system also allows to vary the frequency of one oscillator, so the varying pitch helps to approach a hidden object.
 
Why are you suggesting the BFO method? Is that butter then a PI or VLF (in distance maximizing terms) ?
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top