Blind Squirrel PI.

[DanZ]

Thanks! Yes. I thought I was going to need an adjustment pot in there for it but it reads good with those value components. It stays near zero until a full squeal then it goes to full scale (not slammed full). After you get the settings settled so you hear just a couple clicks every second or so the meter settles down around 1/3 scale and pulses upwards along with metal detected. I just bought 3, 6v SLA's and have them charging so I can out and play later. I want to get to understand the settings better and also see what kind of run time these batteries will give me.
Cheers!

[Toros]

Hi
I`m finishing Blind too. I have changed only transmitter to get linear frequency regulation by poti. It is from Delta pulse and gives range about 196-600Hz and tx width from 30-150us.
Chears
[ATTACH]28427[/ATTACH]
[ATTACH]28426[/ATTACH]

Interesting mod Reiv!
Would you say a little more about how the scheme works. How do you achieve power supply stabilization.

[reiv]

Sure, as I wrote earlier just changed transmiter using LM556 in place of 4536B circut, scheme looks like that:

Change R1 to 100k becasue with 470k there were small range of regulation about to 200Hz.As for now I just turn on this transmit and seems to work fine, missing 2 chips to get all parts, soe have to wait for delivery.
At my PCB there is no voltage stabilization, I will power it from 12V gel aku. Friend of my some time ago built this MD without stabilization and works fine. I think I will only ad some voltage indicator using zener,led and LM358 to be sure when aku charge off.
Meantime making a coil big one 41cm

[sinclairuser]

hi reiv, how do you get the wire in the pipe?

[reiv]

Before glue all, disconnect in one place and insert wire turn by turn, nothing hard to make.

[sinclairuser]

Before glue all, disconnect in one place and insert wire turn by turn, nothing hard to make.

thanks, i kind of figured it was done that way i just wondered.

[bernte_one]

hello reiv,

nice done.
would you post the sprintlayout file here
maybe as zip/rar file?

many thanks

[reiv]

Yeah, but first wanna turn all on and check that is ok.
Now I can upload sprint file 2steps voltage indicator for aku- simple pcb, works like this:
http://www.youtube.com/watch?v=dmWJlPMbqGo
Can use 2 leds or one 2colors, turning potentiometers is how to chose indicate voltage
wskaznik.rar

[Toros]

Many thanks Reiv. I'll try to do your modification. The detector will be much lighter if it can work on 12 volts.

[reiv]

No problem. Soe if U want make it too, here You go "BS" sprint file:
BS2.rar
Just check it once again. I checked few times, but we are just humans

[bernte_one]

thanks reiv
will see what i can do the next nights

[DanZ]

nice job mate, what does the meter respond like?, i mentioned to a mate of mine who works in parts aquisition that i wanted a small u meter for a project and he gave me a box with 4 in i think they are samples as they are all slightly different but the same company, the box says no resale on it, anyway i did not want to add one to what i'm building if it just flicks to the end pointlessly.
so is it readable on the pi?.

Like I mentioned, the meter works good but after today's hunt and experimenting with the detector I found that I was hardly ever looking at the meter. My eyes were mostly on the ground and ears listening. I guess if you were in a noisy environment and trying to pin-point then the meter might come in handy.

[DanZ]

Need to run out and buy a couple SLA's then take it outside to try but it seems to be working with a bench pwr. supply.
[ATTACH]28433[/ATTACH]

After a day with it out in the field I've built two more coils to try with it next. A 6" and a 9.5". Both using 24 SWG (.558mm) enamled copper wire. I'll try the suggested PVC coated/insulated wire for the next coil(s).

[6666]

After a day with it out in the field

What did you find ?

[DanZ]

Lots of trash! lol. I expected as much. It is a field down the road a bit that's used for special events and celebrations. I thought maybe I'd see some coins here and there but mainly wanted to get the feel for the detector's controls, the effects of their adjustments, and battery run time. There are some big lakes around with man made beaches I want to try these new coils on. Hopefully I'll see more than bottle tops. pull tabs, bailing wire, etc.