C.SCOPE CS-7 UMD

[beep]

Hi,

are there any known modifications for the C-SCOPE CS-7 PI detector?

I did an air test with a horizontal coil, but wasn't impressed with the depth of various metal coins/objects. Turning the frequency knob clockwise increased the sensitivity for gold, but a thin gold necklace had to be virtually in the coil to give a signal.

What kind of depth should one expect for a low powerd PI detector?

According to the manual the volume of the waterproof headphones could be managed with a potentiometer on a seperate pcb in the casing. However in the casing there is no seperate pcb for the headphones available. On the PCB for the detector there are 2 potentiometers; RV1 and RV2. Does anybody know what they manage?


Also there is a 2 pin header/jumper on the pcb. Does anybody have a clue what the function of it is?



kind regards, bleep.

[Geo]

See the schematic.... i think is the right

[waltr]

Thanks for schematic Geo.

Beep,
This is a very old design. Interesting they use a PIC16C71 which is pretty obsolete since it a One Time Program.
However, it is a micro-processor based timing which is advanced, more than most of the PI projects in this forum.

Small Gold sensitivity with a PI detector highly depends on how soon after TX OFF it can start sampling.
With the pre-amp and coil design I would not expect sampling any sooner than about 20usec, This means very small gold (remember that a gold chain is many Very Small pieces Not the total chain).

I do not see anything in the schematic worth trying to modify.

[beep]

@Geo and waltr: thank you for your input.

Some information about it on different forums:

"example: cs7 to 16/17 us better than cs4 whose delay is given for 25/30 us !!!"
source: https://www.metaldetectingforum.co.u...ic.php?t=49299

"Back to the CS-7. It is a very well designed, very sensitivity, PI detector with unusual features. One of them being a user can tune the detector to be more responsive to different metals as he is hunting with it. It is the deepest, most sensitive to small gold jewelry, Pi detector I have ever used, and the quality of construction ranks with the White?s which is considered the best."
(dated "1998") source: http://www.treasurenet.com/forum/beach/archives/19990416/messages/9606271647.shtml

"I think the CS6PI only goes down to a 17 or 18 uS delay while the CS7UMD goes down to 15 uS. This is due to the fact that the CS7UMD uses a microprocessor to control pulse timing while the CS6PI uses a 555 timer chip."

"Both the CS6PI and CS7UMD have shielded coils. However, the winding and shielding methods are not designed to work at less than 15uS. Too much inductance and shielding not precisely spaced from the winding."
source: https://www.findmall.com/read.php?34,135094

"Basically the only change that CScope did was to use a microcontroller to generate the timing. This did give some problems initially in not starting up, or having started would unaccountably stop after a period of time. This fault was eventually cured."
source: https://www.findmall.com/read.php?34,1250115


Some of my air test results on the highest possible frequency in my test environment:
- 22 carat gold ring 19 cm
- white gold ring with diamonds 6 cm
- gold token 13 cm
- silver US dime 13 cm
- aluminium ring shaped 9 cm
- lead ring shaped 18 cm

The higher frequency makes it more sensitive for gold items. I couldn't test on the higherst frequency possible as there was some kind of interference on some frequencies. It did detect iron as expected, but it didn't detect coke. I first wanted to test it on a different table, but it detected the minor movements of the lamp shade which is located on a bigger distance (55 - 90 cm) from the coil then the items used in the air test. There is a short German video on youtube in which it discriminates a bottle cap, but don't know if it's a modification as the man in the video states "it's something you normally don't see".





air test results (same as above):


air test setup:


some pictures of the cscope cs-7: