Hays Mark 1 schematic

[Reg]

I couldn't find the schematic for the Hays tr detectors so I thought I would post one for those interested to the Hays Mark 1 and Mark 2 metal detectors. As far as I know the only difference between the two is the coil size.

Reg

[homefire]

Cool Beans and Thank you.

[Anwar2]

thanks Reg
Iwould ask there are any good small size coin and gold pic finder circuit schematic and good deep 50 -100 cm
Ihave built Tarsos project its working but not small siz of metal and not than 15 cm deep

[Reg]

Hays 8 inch coil info

Here is the info on the 8" coil used on the Hays units. The information was provided by Bill Hays on a different forum so I took the liberty to copy his information and post it here.

Reg

8" COIL WIDINGS, RECEIVER TOTAL TURNS 89 TAPED AT 45 TURNS, WOUND ON 5" I.D. COIL FORM,
TX COIL FIRST TAP FROM STARTING WINDING IS 10. SECOND TAP IS 15 TURNS FINISH WINDING 30 TURNS ALSO WOUND ON A 5" I.D. COIL FORM
BOTH WINDINGS ARE #31 WIRE.

[Reg]

I talked to Bill Hays the other day and he informed me that this same detector was made under a different name early in its existence. Also, the schematic was different since it had fewer transistors.

Now, here is the interesting part, the schematic posted can be used for the older versions but only part of it. The first part of the schematic up to 5 transistors was the schematic of the early model. Additional circuitry was added to increase sensitivity at a later date.

So, the schematic still works even for the earlier models. You just use less of it.

On a different note, Bill would like to provide some history of his detector and metal detectors in general and how they evolved. Our brief conversation indicated he is a wealth of information in this regard. As an example, early in the history of metal detectors, there was no listing for metal detector in the phone book. So, Bill offered to take out adds across the country in phone books providing they added the metal detector listing. Thus, a new listing begin to show up in the phone books across the country.

More interesting bits of history to come once Bill provides the info. He buzzed off names that I recognized and others that I had no idea who they are. So, hopefully, more info will be posted about the evolution of the metal detector, especially at its early history.

Reg

[Melbeta]

That had to be Dumais Electronics Corp...

Here is Dumais Electronics Corp advertisement featuring the Hays Metal Detector. They made some pretty good claims here. You did some testing of the Hays unit, would you say these are a bit out in left field? Or were they that good?

If the Dumais is clearly different, would it be possible to get a a schematic of this Dumais unit?
Melbeta