GEB

[green]

Being discussed on more than one thread. Didn't know where to put it so I'll start another. A circuit I've been using on the bench, been modified and rewired a few times. Has some timers not needed for coil off GEB. It works. Don't know how to program micros, been a long time since I did logic. Trying to learn PI and making coils I decided to go the logic chip route. I'm hoping someone that does micro's would feel sorry for me and do one and post it. Hard wiring logic with soic chips isn't fun. I see I didn't reduce the picture enough and you have to scroll down.

[greylourie]

The micro seems to be a step in the right direction. Theres a couple of projects that could be looked at here on Geotech.

Carl did the HH2 with a pic, and theres some work contributed from a few on that. Carl also did the groundwork for a usb pic project. Then there is a huge amount of stuff done with Dspic (?), by Moodz. He went on to work some with a ready made board.

If you want to use a micro, there is just so much choice. Someone recently posted links to stmicro boards. Another one that wont hurt the pocket if a screwdriver/probe slips, is the $4 PSoC 4 CY8CKIT-049 4xxx Prototyping Kits. And for that there is a load of example projects (Psoc4 Pioneer) from which useful bits could be cherry picked and ported over.

http://www.cypress.com/?rID=92146
http://www.element14.com/community/t...ullThread=true

[green]

scope pictures of integrator switch control with and without GEB

[green]

The micro seems to be a step in the right direction. Theres a couple of projects that could be looked at here on Geotech.

Carl did the HH2 with a pic, and theres some work contributed from a few on that. Carl also did the groundwork for a usb pic project. Then there is a huge amount of stuff done with Dspic (?), by Moodz. He went on to work some with a ready made board.

If you want to use a micro, there is just so much choice. Someone recently posted links to stmicro boards. Another one that wont hurt the pocket if a screwdriver/probe slips, is the $4 PSoC 4 CY8CKIT-049 4xxx Prototyping Kits. And for that there is a load of example projects (Psoc4 Pioneer) from which useful bits could be cherry picked and ported over.

http://www.cypress.com/?rID=92146
http://www.element14.com/community/t...ullThread=true

I know zero about micro's but for the price of a hamburger I guess I can try. Thanks I hope

[greylourie]

I know zilch about micros, but Cypress put a lot of PR into trying to convince people that you can use the product - and can get your feet wet without writing code. They offer loads of examples. Even if the bits inside are not as high spec'd as offerings from others..... the price is good enough for getting ones feet wet.

I watched one of their videos where some of those cheap female pin headers were soldered to the holes along the side of the board, and in minutes the user had loaded a cap sense program. And the darned thing was picking up and reporting the movement the finger sliding along the row of connectors. Just like your mobile phone or tablet screen does. Amazing.

[6666]

What micro pulse train are you wanting ?

[green]

What micro pulse train are you wanting ?

What I have seems to work. Right now a circuit that does what I have with fewer packages and less wiring.

[6666]

Hi Green
could you maybe draw the pulse train that you need something like in this example, and I'll try and produce it, thanks.

[green]

Hi Green
could you maybe draw the pulse train that you need something like in this example, and I'll try and produce it, thanks.

What I'm using on the bench. The times are a guess for small gold. The 90.4usec is what it takes to GEB the ground samples I have with the preset times listed on the graph. Works on the bench. Maybe there is a better way, open to suggestions. Removed added sentence

[green]

New schematic. Tried to reduce number of chips. Haven't built it yet, not sure if it works.

[6666]

Good work

[green]

Wired controller reply #10 to see if it would work. Oscillator wouldn't auto start on power up. Used one of the unused gates to start it . Everything seems to work. The times on the schematic are calculated. The circuit times are close to calculated. Added a switch to turn GEB on or off if not needed.

[green]

Used controller_4 to chart some data with and without GEB

[Chet]

Hi Green
Was the clay left in place during the "no GEB" measurements? Do you have any thoughts or conclusions on your overall results?
Thank you,
Chet

[green]

Hi Green
Was the clay left in place during the "no GEB" measurements? Do you have any thoughts or conclusions on your overall results?
Thank you,
Chet

The reading is the change from no target to target. The bag of clay measures about 200mm x 150mm x 80mm thick and didn't cover the 200mm ID coil. The clay wasn't there for the coin measurements, just to show GEB works, no change in reading when adding the clay. I just tried the US nickel at 100mm with and without GEB, with and without the clay between the coin and coil. The clay being there didn't change the difference readings. I'm still trying to figure out what timings look the best. Probably makes a difference what your looking for. Low time constant targets need to sample early. Longer GEB sample times amplify long decay targets and increase the hole time. KR has been trying changing pulse rate and EF delays. Lots of things to try.