Rating the projects

[golfnut]

All, I have made a kit from here, and am about to make a few more.

In order for people to get the kit/project they require, I would like viewers of this forum to quickly make up their mind which kit to build via user feedback in the form of a score / ranking system.

We may use smileys?

e.g.

Surf Pi
Ease of build -
Initial setting up -
Ground balance in the field -
Sensitivity 10" mono -
Cost/availability/part sourcing -

If useful we could Sticky and maintain

Steve

[Comp]

Good idea, like it!!!!

I see you rated the sensitivity as only 2 smileys,.... I have just put a Surf P.I. (1.2) together, and found it was low sensitivity, (my first play with a MD,) on investigation, I spotted that the resistors R18 & R22 were marked wrongly on the PCB legend, when I swapped them over, I got a marked improvement in detection depth, might be worth a look see on yours.....



Cheers, Fred

[Hannu]

I spotted that the resistors R18 & R22 were marked wrongly on the PCB legend, when I swapped them over, I got a marked improvement in detection depth, might be worth a look see on yours....

I swapped resistors and made quick test without any adjusting. Now US 1 cent coin detected from 24cm (was 15cm before).

Thanks.

[golfnut]

Sorry Fred, that was a 'format' example - not a real review.

Steve

[6666]

Just buzzed the pcb you are right
Pins 1 & 2 of u3a do go to R 18 not R22 as per the schematic
I will change mine and see what happens

Good pick up on the mistake, what made you check it ?

THANKS

[Comp]

Just buzzed the pcb you are right
Pins 1 & 2 of u3a do go to R 18 not R22 as per the schematic
I will change mine and see what happens

Good pick up on the mistake, what made you check it ?

THANKS

Hiya!!!well, as above, really,... It was my first 'build', and I was disappointed with the depth detection, and made about 6 different coils, but none seemed much better than the others,I cold only detect a 2p (even a new, ferrous one!!) to about 1 1/2" to 2". I also noticed that the 'tune' pot seemed to do very little. I stuck my meter on the 'R18', looking for a negative feed to the trimmer, and 'Eureka'!! swapped em over, and now hit a 2P at 6 to 7 inches, easy. It may not make any/much difference on your boards, due to other circuit tolerences, but, as my missus says, every inch helps...

So, now, back to the 'tweaking',..

Cheers Guys, Fred

[ApBerg]

Just buzzed the pcb you are right
Pins 1 & 2 of u3a do go to R 18 not R22 as per the schematic
I will change mine and see what happens

Good pick up on the mistake, what made you check it ?

THANKS

Hello,

Look at the sprint file, there are also the values, put in Sprint Layout all layers on, there are many parts on a small place...

You can find the zip file with the sprint file at http://www.geotech1.com/forums/showthread.php?t=13810&page=2 post # 45

If you find errors let us know..

Best regards.

Ap

[silverdog]

mmm, seems there is some discrepancy here, probably from different versions over time

Attached are the pcb and schematic I have

I think we all agree the board is ok, the silkscreen has part numbers so if we can agree on the required schematic changes, i will amend and update the copy on my shop that most people seem to use with this kit

regards

well spotted though - it only took 1 year for someone to notice

Silverdog

[Comp]

Yep, the circuit schematic is correct, as is the pcb etch,... its just the resistor labelling on the board,.. I'm afraid I was working from just a parts list, and the pcb, so I put the two resistors in the wrong place......

Working really well, now, though,... (sure I can tweak a couple more mils out of it, though!!!)

Cheers, Fred

[silverdog]

ok, I've updated the schematic and partslist in my shop to swop R18, R23

Silverdog

[maikl]

Hi silverdog. I think you are supposed to replace R18 with R22 and not the R23. It is obtained following: R18=100K and R22=47K.

[silverdog]

I knew that

Somewhere between reading and sriting my brain changed 22-23

Corrected now

[ApBerg]

Hello Friends,

Made a jpg that can be helpfull..? if somebody spots a mistake.. (hope not) well tell it then...

Best regards.

Ap

[golfnut]

Clearly ranking performance draws welcome attention.

Seems to raise the quality of the finished product.


for sensitivity now?



Steve

[golfnut]

Hi Fred I notice the Gate on the FET has no bleeder resistor on it. Maybe a 1k on there to gnd may help sharpen up the off time and give a little more kick on the coil!

I dont have a built Pi to try nor scope..

Steve