IDX-PRO+VDI

[Mullihaka]

Nulling the coils?

What is the target in nulling the DD coils? Do we need a minimum voltage at the input of the preamp, certain phase shift between TX and some point in the circuit or something else?

All hints appreciated.

[verotopasera]

[eduardo1979]

Hello Eduardo which of the two coils are correct wire RX 0.15 - 270 coils or RX wire 0.18 - 270 turns

TX=35 Turns-wire 0,70+1uF parallel capacitor.
RX=270 Turns-wire 0,18+33nF parallel capacitor.
For housing DD27cm.

[verotopasera]

Hello Eduardo which of the two coils are correct wire RX 0.15 - 270 coils or RX wire 0.18 - 270 turns

[MAURICE]

VDI layout

Hi and Greetings
Here is my layout. I have not made provision for a little heat sinking around the regulator. Perhaps a little tin profile soldered on may suffice.
This is my first time for using smd parts.(PIC and REGULATOR)
There are 8 links. Included in zip are:
top jpg
bottom jpg ( reflected image )
both
diptrace source files.
Any quires and I will be more than happy to help.

[shansov]

TX amplitude=16V

eduardo1979 where to get the amplitude? I have AC 2.4 V TX.

[Wiltran]

Hi Holyuser.
Thanks for your reply and posting the link.
It looks very good but I have to make my own boards with single sided PCB.
They have a few links but everyboard is homemade.
If someone needs my layout I will post.
Best Regards
Maurice.

Excellent work Maurice! everyone who builds their own boards from scratch is well aware of how much work it takes to make a well layed out board that works. In my opinion , your work is greatly appreciated! thanks - please post layout.

[bernte_one]

hello maurice

please post yout layout thanks

regards bend

[MAURICE]

Hi Holyuser.
Thanks for your reply and posting the link.
It looks very good but I have to make my own boards with single sided PCB.
They have a few links but everyboard is homemade.
If someone needs my layout I will post.
Best Regards
Maurice.

[holyuser]

Congratulations for hard work, but there are already published version of the VDI board based on SMD PIC16F690 here: http://www.md4u.ru/forum/download/fi...7f9b66a5964b33

[MAURICE]

VDI 690 layout

Hi all.
I have done a layout for vdi 690 NB not built or checked.
It features SMD for the 16f690 and the MCP1703 regulator. The other components being leaded. I post first schematic , Holyuser please check to see if it is correct and make comment. Your help greatly appreciated.
If all looks well will post board layout.
Regards
Maurice.

[shansov]

without coil DC 7,25 V constant, the coil TX1.5 V AC.

[eduardo1979]

eduardo 1979 why such a low amplitude of 7.25 V? where to find the error?

Without connecting the TX coil to the detector, you can not measure the amplitude. You have to connect the TX coil with a metal detector to measure either the amplitude.

[eduardo1979]

hi dear eduardo 1979
first of all i should thank you for this great project presented here , by the way i couldn't locate TX coil capacitor , if possible locate it for me on the schematic witch you have posted

TX capacitor is tucked inside the coil and has the capacity to 1uF. In the scheme TX and RX capacitors are not. These capacitors are put into the coil. The capacitor is 1uF TX and the RX is 33nF capacitor.

[jack_hunter1972]

hi dear eduardo 1979
first of all i should thank you for this great project presented here , by the way i couldn't locate TX coil capacitor , if possible locate it for me on the schematic witch you have posted