'KROT2-XM' (mole), new project Xmega32

[WM6]

Disconnect coil and beeping stops.

Probably still problem with coil shielding.

Check all path of coil wire shielding (you need to screen: not only coil and coil cable, but connector and RX hot wire from PCB to connector too). Coil shielding should be connected to RX ground:

http://www.geotech1.com/forums/showt...879#post184879

[gurdal]

merhaba bobin resonans https://imagizer.imageshack.us/v2/73...910/VgG8zJ.jpg https://imagizer.imageshack.us/v2/73...661/wPtE9h.jpg

[Wiltran]

Probably still problem with coil shielding.

Check all path of coil wire shielding (you need to screen: not only coil and coil cable, but connector and RX hot wire from PCB to connector too). Coil shielding should be connected to RX ground:

http://www.geotech1.com/forums/showt...879#post184879

Gurdals mole2 does not appear to be shielded whatsoever and is not beeping in the video! I wonder what is the function of R10, and if increasing the resistance would eliminate beeping. It seems as if the Mcp601 is getting overloaded. My next step is scrapping this board and building a SMT board if I knew what was the best version.

[WM6]

Gurdals mole2 does not appear to be shielded whatsoever and is not beeping in the video!

Maybe Gurdal has low EMI environment.
Try to check your configuration in field, away from civilization EMI sources.

[Wiltran]

Maybe Gurdal has low EMI environment.
Try to check your configuration in field, away from civilization EMI sources.

Its true Ive never checked stability outside my house.

[gurdal]

mole tx frequ rx frequ.

tomorrow coil resonance in the garden



Could you please give details coil

[WM6]

mole tx frequ rx frequ.

RX and TX F should be different.

According author: RX frequency should be set about 20% (10-20%) lower than TX frequency.

Par example: if your TX frequency is set to 10kHz, then your RX frequency should be tuned at 8 to 9kHz (say 1.5kHz lower)

It is recommended that frequencies are set in range of 6 to 12kHz.

[Wiltran]

Krot2 version 3.4 SMD

I built version krot2xm 3.4 SMD board, and I cant get it to display on a 2X16 LCD display which previously worked on the dip version krot2XM. I got it working on a 3.3 volt display. Does anyone know what if any modifications to make to get version 3.4 working on a 5V display? Believe it or not this 3.4 version double sided board still chatters with false signals. As Andrew pointed out, maybe the chattering would stop if I used the detector away from city noise. If that is the case, this metal detector would be perfectly useless to me, as I detect a lot in city parks and lots.

[reiv]

No, Krot 2XM is really stable even in "city noises" soe don`t wory. Your problem with LCD might be contrast regulation, with mine was the same, have to change resistance to zero, it was R19 i think

[Wiltran]

Mole2 Xm smt board

Hi Reiv, good to see someone who has had success with mole. I tried a 5 volt display and replaced r19 with a 25k pot, but still did not work. It works good with a 3.3V display but I cant seem to be able to change the contrast. This same 5 volt display worked fine with the mole2 Xm dip version I built. Did you build the V3.4 smt board by TCB? As far as the instabilty, the VDI changes rapidly and beeps. I set Urz=0 A=0, and followed the basic instructions for setup. and I used calculations with an inductance meter for winding coils and setting the frequency. I am missing the boat, somewhere, but I dont know where to look.

[reiv]

Yes, I have V3.4 too and it is 100% correctly

At first start up had problem with contrast too (also 5V LCD, with white backlight) soe i play with R19 and R27. Maybe try to increse contrast at menu (I know that can`t see anything) but try:
turn on,wait at last beep,press and hold for second menu button,relase, then press it short 2 times more, and then right arrow to increse the contrast.
About Your chattering, first check if he beeps without coil, if yes problem is in components of PCB. Or You may try go outdoor only with PCB and battery and check if he will react different (maybe strong "noises" in Your appartament), if the same, problem with components. Maybe AD8091, hard to say, Mine KROT2XM without coil at sens. S22,gain-2 is totally quiet, S11-ocasionally beep.
Good luck

[Wiltran]

krot2

Thanks for the picture Reiv, I noticed that you used two large 100 mfd. tantalum caps for C26 and C3. Could you tell me what values of R19 and R27 you ended up using? My detector is perfectly quiet without coil but starts beeping when I attach coil. Any close up picture of back side of board? thanks

[reiv]

If, remember right R19=0 ohm, R27 no change.
Soe Your coil is faulty. What kind of cable (double shielded)? If moving cable and chatters are bigger-change it, concentric S-VHS is good. What value of Rx You have, and what kind of shielding U are using? Resonances are ok?
Sure I have only those:

[Wiltran]

krot2

Thank you for the pictures! I got the display to work on 3.3V i put a 25k pot at r19 and it ranged in around 3.5k for good contrast. I left R27 at 10k. So now its back to fix the beeping. I think it is a cheap S video cable. two sheilded cables in side, but no outer shield. my other cable I tried is two double shielded with an outer shield but still beeped! I only made calculations on the coils by using an inductance meter. It seems to use the most current at 8khz. So I assume thats where its working most efficiently. But I dont have any way to check the actual resonance.

[reiv]

My cable S-VHS is build like this, and works perfectly:

No need to use inductance meter, just simple generator and osciloscope with Your LC circut, check were is max amplitude at wich freq. When Your Tx has 8kHz, Rx must be about 6.5kHz. What is Your Rx voltage measuring by KROT display?