BFO metal detector

[yhl]

student bfo metal detector

[yhl]

look

look

[WM6]

Hi yhl,

interesting design and nice manhattan board solution. Congratulations.

What are testing results?

[yhl]

q

This one can hear a Taiwan one dollar coin (about the same size as 1 cent US) up to 100mm away.

[jap]

Hi yhl
C13,D1 In case of difficulty in getting them what is the alternative.
-Is your style of component assembly improvement performance or can be assembled on PCB Normal.
Thanks,
best time
j.

[WM6]

Hi yhl
C13,D1 In case of difficulty in getting them what is the alternative.
-Is your style of component assembly improvement performance or can be assembled on PCB Normal.
j.

Probably you can get here some ideas how to make variable tuning capacitor (C13).

http://www.sm0vpo.com:800/use/tuning_caps.htm

You can also use part of thin both side Cu-coated PCB, solder two wire on both side and then cut it of in small pieces for (fixed) tuning.

D1 can be replaced by almost any other HF germanium diode like OA91 etc.

[jap]

Hi WM6
Thanks,
best time
j.

[WM6]

This one can hear a Taiwan one dollar coin (about the same size as 1 cent US) up to 100mm away.

Not bad results for 12cm dia coil.