metal proximity

[msovais]

i need to know IC for metal proximity except cs209a?

 

[chemelec]

A TDA0161 is also simular.

 

[msovais]

hey can i use 150uh inductor instead of coils?

 

[msovais]

and wats the detection range in this...

**broken link removed**

 

[jpanhalt]

hey can i use 150uh inductor instead of coils?

I used the TDA0161 and commercially available unshielded, open "bobbin" inductors, such as the Miller power inductors (Digikey p. 1216, P/N M8573CT-ND), with inductances of 470 and 1000 uH and got very good detection at 1 cm, and decent detection at up to 2 cm. My target was a 3/16 steel rod. A larger diameter coil might give more range. John

 

[chemelec]

I used the TDA0161 and commercially available unshielded, open "bobbin" inductors, such as the Miller power inductors (Digikey p. 1216, P/N M8573CT-ND), with inductances of 470 and 1000 uH and got very good detection at 1 cm, and decent detection at up to 2 cm. My target was a 3/16 steel rod. A larger diameter coil might give more range. John

Not All Coils and Cores are EQUIL.

A Pot Core with Litz Wire will give the Best Results.

Range is Also Dependent on the TYPE of metal being detected. Sorry I won't comment on Specific ranges, but it is Not Made to detect at any Great Distance, No matter What you do.

 

[jpanhalt]

A Pot Core with Litz Wire will give the Best Results.

The results I gave were intended only as a brief summary of a series of experiments I did. Those experiments looked at oscillator frequency (28 to 60KHz), inductance, wire (Litz vz. magnet wire), and free-air resonance frequencies of the coils. At the frequency ranges tested, Litz wire made no difference. I also tried a few pot cores and got virtually the same results.

Thus, using small coils of the size described and 3/16" wire (hard-drawn, high-carbon music wire) and under the conditions of my experiments, the TDA0161 can be depended to provide good sensitivity up to 1 cm, and usable sensitivity up to almost 2 cm; however, to get above 1.5 cm, the settings are a bit "touchy."

On the other hand, with a two-coil detector (basically a Zircon metal detector -- a reverse-engineered schematic is available on the internet), I got sensitivities of 5 cm or more.

John

 

[chemelec]

The results I gave were intended only as a brief summary of a series of experiments I did. Those experiments looked at oscillator frequency (28 to 60KHz), inductance, wire (Litz vz. magnet wire), and free-air resonance frequencies of the coils. At the frequency ranges tested, Litz wire made no difference. I also tried a few pot cores and got virtually the same results.

Thus, using small coils of the size described and 3/16" wire (hard-drawn, high-carbon music wire) and under the conditions of my experiments, the TDA0161 can be depended to provide good sensitivity up to 1 cm, and usable sensitivity up to almost 2 cm; however, to get above 1.5 cm, the settings are a bit "touchy."

On the other hand, with a two-coil detector (basically a Zircon metal detector -- a reverse-engineered schematic is available on the internet), I got sensitivities of 5 cm or more.

John

Never seen that Zircon Schematic.

But if you want distance, why not just build a Good detector and get 10 inches or more on a Quarter.

Take care...Gary

 

[jpanhalt]

But if you want distance, why not just build a Good detector and get 10 inches or more on a Quarter.

There was a size limitation in the design. It had to be less than 0.75" across. Eventually went with back-scattered IR.
John

 

[msovais]

Never seen that Zircon Schematic.

But if you want distance, why not just build a Good detector and get 10 inches or more on a Quarter.

Take care...Gary

hey can i get some idea or schematic to build 10 inch or so detector using tda0161 because 1 cm or 2cm are very much less....
...wat will be the values of inductor and capacitor