Look self-made VLF detector on the microcontroller AVR AT90S2313-10

[sevzirfo]

Hi!

Features of the circuit - the microcontroller AVR AT90S2313-10 generates pulses with adjustable frequency from 2.84 kHz up to 74.4 kHz and adjustable phase from 0 up to 180 degrees. The opportunity of adjustment of frequency and phase considerably simplifies adjustment of the search coil, it is possible to use firm coils from VLF metal detectors under them easily to be arranged. The adjustment of frequency or phase is carried out by pressing of buttons S2, S3, S4, S5. The current meaning(importance) of frequency and phase can be kept in non-volatile memory EEPROM, what at the following inclusion of the detector the circuit at once began to work on the chosen frequency and phase.
The microcontroller with my program can be established in many simple circuits: Whites Classic, Tesoro Eldorado, Tesoro Bandido2uMAX. The program and circuit look on my site.

Enjoy!



http://sevzirfo.narod.ru/md.htm

[Chris]

Re: Look self-made VLF detector on the microcontroller AVR AT90S2313-10

Hi Sevzirfo

thanks for sharing your design with the forum. I had a quick look at your diagram. Have you activated the internal pullup resistors in the software? If not S2 to S7 need an additional pullup resistor (4k7).

Chris

[sevzirfo]

VLF detector

Hi Chris

I activated the internal pullup resistors in the software. Program Test OK!

sevzirfo

[PhilippeM]

Re: Look self-made VLF detector on the microcontroller AVR AT90S2313-10

Pretty and simple design!!!!
Can you give us more information about the TX and RX coil that you use : Number of turn and daim of wire.
I understood that this design was expected for a lot of coil because the fréquencie can be ajust but i'm curious about your coil ;o))).
With this design ,can you give us some measure of the sensibility in air for some target?

Thanks a lot
PhilippeM

[Willy Bayot]

Re: Look self-made VLF detector on the microcontroller AVR AT90S2313-10

Interesting.
Is there any AVR source available?

[nickf]

Re: Look self-made VLF detector on the microcontroller AVR AT90S2313-10

Very interesting !

A very minor point: is the crystal supposed to be 10 Mhz rather than the 20 Mhz shown ? (I'm looking at the GIF Mod 0.3 circuit)

[sevzirfo]

Crystal

Hi!

Overclocking is necessary for smooth change of frequency and phase

[sevzirfo]

Coil & sensibility in air

Hi Philippe!

The coil for tests - rectangular DD
Width - 13.5 cm
Length - 21,5 cm
TX - 60 coils of a copper wire in varnish isolation by a diameter 0.25 mm
RX - 100 coils of a copper wire in varnish isolation by a diameter 0.25 mm
Range of detection of a copper coin by a diameter 25mm on air in - 18cm
Frequency 8 kHz

sevzirfo

[PhilippeM]

Re: Coil & sensibility in air

thanks a lot for this informations
Bests regards
PhilippsM

[behrooz]

Re: Look self-made VLF detector on the microcontroller AVR AT90S2313-10

>Hi!

>Features of the circuit - the microcontroller AVR AT90S2313-10 generates pulses with adjustable frequency from 2.84 kHz up to 74.4 kHz and adjustable phase from 0 up to 180 degrees. The opportunity of adjustment of frequency and phase considerably simplifies adjustment of the search coil, it is possible to use firm coils from VLF metal detectors under them easily to be arranged. The adjustment of frequency or phase is carried out by pressing of buttons S2, S3, S4, S5. The current meaning(importance) of frequency and phase can be kept in non-volatile memory EEPROM, what at the following inclusion of the detector the circuit at once began to work on the chosen frequency and phase.
> The microcontroller with my program can be established in many simple circuits: Whites Classic, Tesoro Eldorado, Tesoro Bandido2uMAX. The program and circuit look on my site.

>Enjoy!