C.scope SC4PI Mod

[porkluvr]

YUP, Porkluvr is spot on! Increasing the XTAL frequency to 6MHz has a two fold effect, yes, sure the Tx frequency goes up and your sample delay drops, but what else is going to drop?? PULSE WIDTH and probably by 25% or MORE and I suspect that the 4PI doesn't "hard drive" the coil anyhow (top out on Imax) in order to save battery power .

If you are right about CS4 not hard driving the coil, that would mean battery current should be roughly the same whether at 1x or 1.5x crystal frequency, because an increase in PPS should be met with a proportional reduction in PW.

I was probably just being alarmist, hinting that battery current might go up. Anyway, that's easy enough to measure.

I do wondering about why anybody would want to potentially ruin a perfectly useful machine (not that I haven't done it myself). Answer: for a chance at better sensitivity to small nuggets. I realize that before a change in timing is to have any good affect, the coil also needs changed... requiring a different damping resistor, and also a recalculation of series resistance. No trivial task. And in the end, if your machine still works at all, any increased sensitivity to small stuff will likely be met with a decrease in sensitivity to bigger stuff. Ow.

Yes, there are much better platforms to hack, but I am hoping that if geroms gets to a point to where progress dead-ends he can revert back to the original configuration without too much trouble, with no permanent harm done.

I have in the past been party to advising someone on what I thought should have been a simple straight-forward modification, only to find that the "easy job" went sour due to some unfortunate detail, and repair was beyond the scope of the owner. It sucks.

[geroms]

Thank you for your precious help and advice, sorry for my poor English.

Is a coil of sd2200 is a good choice as a fast coil?

Is it possible to read the program PIC16C711? The idea is to replace it with a PIC18F4550 with a USB port?

At first an improvement of 10 to 15% of the sensitivity to small nuggets would be enough to send the first detector to Africa country.

I want to give this detector to a African, He will have better working conditions than to digging tunnels to find 1 or 2 gram of gold per day.
This is my modest humanitarian involvement.

[Qiaozhi]

Is it possible to read the program PIC16C711? The idea is to replace it with a PIC18F4550 with a USB port?

The code in the PIC is almost certainly locked, which will not allow you to download it. Even if this was possible, you would still only have the firmware, and would need to disassemble the code. Good luck with that.

Your best bet is to monitor the various pins of the PIC with a scope, and (with the aid of a back-engineered schematic) figure out what each pin is being used for. Armed with this knowledge it would be possible to re-write the code from scratch for a different PIC.

So, why do you think you need a USB port?

[porkluvr]

<snip>
Is a coil of sd2200 is a good choice as a fast coil?
<snip>

Could you describe the coil? Is it a monocoil, or a DD?

You are looking for a monocoil preferably but your PCB could probably be modified to accept one of the other types.

[geroms]

The code in the PIC is almost certainly locked, which will not allow you to download it. Even if this was possible, you would still only have the firmware, and would need to disassemble the code. Good luck with that.

Your best bet is to monitor the various pins of the PIC with a scope, and (with the aid of a back-engineered schematic) figure out what each pin is being used for. Armed with this knowledge it would be possible to re-write the code from scratch for a different PIC.

So, why do you think you need a USB port?

And replicate the PIC16C711 04 / P PIC16C711 on another 04 / P, is it possible?

The USB port is for later project with a PC or little but very powerfull Linux box with 300 MHz MIPS processor.

[geroms]

Could you describe the coil? Is it a monocoil, or a DD?

You are looking for a monocoil preferably but your PCB could probably be modified to accept one of the other types.

The cs4pi pulse frequency is variable from 1 to 4 MHz. I guess their coil is an average value.
With Increasing the frequency of quartz, the pulse frequency also increases with a reduction in the delay.

It would be sufficient to adjust only the impedance value and the quartz, what do you think?

[Qiaozhi]

The cs4pi pulse frequency is variable from 1 to 4 MHz. I guess their coil is an average value.
With Increasing the frequency of quartz, the pulse frequency also increases with a reduction in the delay.

It would be sufficient to adjust only the impedance value and the quartz, what do you think?

I assume you actually meant 1 to 4kHz?

[geroms]

Oups, yes it's 1 to 4khz (4 000 pps)