[x] Welcome at THunting.com!

A fun place to talk about Metal Detecting, Treasure Hunting & Prospecting. Here you can share finds and experience with thousands of members from all over the world

Join us and Register Now - Its FREE & EASY

THunting.com
Treasure Hunting & Metal Detecting Community
   
Advanced Search
*
Welcome, Guest! Please login or register HERE - It is FREE and easy.
Only registered users can post and view images on our message boards.
Did you miss your activation email?

Login with email, password and session length
Or Login Using Social Network Account
News:
Pages: 1    Go Down
Print
Share this topic on FacebookShare this topic on Del.icio.usShare this topic on DiggShare this topic on RedditShare this topic on Twitter
Tags:
0 Members and 1 Guest are viewing this topic.
Offline Mike In2mudTopic starter
Bronze Member
*

My Motto:- Simplest is Best.
Join Date: Feb, 2009
Thank you2

Activity
0%
Male
United Kingdom
Posts: 148
Referrals: 0

745.00 Gold
View Inventory
Windows NT 6.3
Windows NT 6.3
Chrome 46.0.2490.80
Chrome 46.0.2490.80

Awards

Minelab Safari     Garrett Ace 250,       Garrett Pro Pointer       "The Homer" (Home Built Model)
« on: November 04, 2015, 01:50:02 pm »
Go Up Go Down

Hi Golddust Carl,
I liked your ideas you had using a different approach to PI detectors in your first posts on this site.

I've been trying to follow the progress of your PI  you posted under PI Designs & Deepseekers >New Idea and Please, more clear schematic!
I have built the circuit shown in your schematic and have used 22 SWG (0.711mm), which is equivalent to your  21-22 AWG (0.643-0.724mm) to wire the coils, they are tightly bound with Spiral-Wrap. The 8" coil is 407uH  and the 6" coil is 430uH.
My problem is firstly that I can only get a maximum of 5-6us pulse at the resistor divider, the secondary point (no target), whereas you get a 10us pulse.
Secondly I cannot even vary the pulse enough to set-up the Ferrous, Non Ferrous levels unless I heavily dampen the primary coil using an 82R resistor across it, which gets very hot. The circuit is drawing 400mA.
I cannot get any sensitivity from the coil even using a large piece of copper and separately a large piece of iron. If I use a higher value resistor to damp the coil then the width of the pulse is reduced significantly below the 12us. threshold.
If I carefully look at the pulse at the resistor divider, I can see no change in the shape of the pulse, when metal is brought near the coils.
I must confess I am stumped at the moment, all the problems appear to centre around the coil area, but I think I have constructed them both correctly.

Best regards Mike


Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,61089.msg303228.html#msg303228




Logged
Offline geoscash1
Pull Tab
*

Mood:Happy
Happy

Jack Of All Trades, Master Of a Few
Join Date: May, 2014
Thank you6

Activity
0%
Male
United States
Posts: 21
Referrals: 0

120.00 Gold
View Inventory
Windows 7/Server 2008 R2
Windows 7/Server 2008 R2
Mozilla compatible
Mozilla compatible

WWW Awards

PI Treasuresweeper v-1.0, Minelab Goldenhawk, Mirage PI, Mirage CBSII, Minipulse plus, BH Sharpshooter II, SM PRO Surf PI, Barracuda
« Reply #1 on: December 12, 2015, 08:44:00 pm »
Go Up Go Down

Hi Mike,

Saw your post and then reread the old thread, were you ever able to get this working or are you still having problems with it?

Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,61089.msg305247.html#msg305247




Logged

You are not allowed to view links.
Please Register or Login

http://www.treasuresweeper.com

Offline Mike In2mudTopic starter
Bronze Member
*

My Motto:- Simplest is Best.
Join Date: Feb, 2009
Thank you2

Activity
0%
Male
United Kingdom
Posts: 148
Referrals: 0

745.00 Gold
View Inventory
Windows NT 6.3
Windows NT 6.3
Chrome 47.0.2526.80
Chrome 47.0.2526.80

Awards

Minelab Safari     Garrett Ace 250,       Garrett Pro Pointer       "The Homer" (Home Built Model)
« Reply #2 on: December 13, 2015, 05:47:30 am »
Go Up Go Down

Hi Geoscash1,

The first circuit I built (the one mentioned above), I tried to cut down on the IC count to fit my Control Box, I succeeded in getting it working, BUT I couldn't get the exact 250uS pulse width at the MOSFET, which is important.

After PM e-mails with Golddust Carl I completely rebuilt the circuit as per his drawing. The circuit now works fine.

I wound both the coils near to 400uH and set up the damping, but as yet I can only detect large chunks of metal. I cannot detect coins at all.

Large Iron is now detected at 3” and Large Copper at 2” with the sound just starting in the background. If I set it to be just silent first, then nothing is detected.

That is the stage I am at now, still trying but haven't got there yet.

Best regards Mike.


Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,61089.msg305282.html#msg305282




Logged
Print
Pages: 1    Go Up
Jump to:  

Powered by SMF 1.1.19 | SMF © 2005, Simple Machines | Sitemap
Copyright THunting.com