HH Meter

[Unregistered]

Hi,

How would I add a meter to the HH PI detector, where would I connect it for correct reading.

Thanks

[Unregistered]

Maybe check Gary`s PI for an idea on how could do it, but maybe HH not useable with meter??

[Carl-NC]

What do you mean by "correct reading?" You can add a meter at the output of the final opamp. How you do it depends on the meter you want to use.

- Carl

[Unregistered]

What do you mean by "correct reading?" You can add a meter at the output of the final opamp. How you do it depends on the meter you want to use.

- Carl

Thanks Carl, just wanted something for easier reference, to connect standard digital panel meter(or vu met.), so for a given item, coin, or gold ring etc. could make note of number, if you know what I`m trying to explain.
Output of final opamp is that round TP9.

Cheers
Nugget

[Carl-NC]

What it sounds like you want is an ID meter. Can't do that on HH, or just about any PI, as PI does not provide conductivity information. If you add a meter to HH, it will deflect the same for any metal.

- Carl

[Unregistered]

What it sounds like you want is an ID meter. Can't do that on HH, or just about any PI, as PI does not provide conductivity information. If you add a meter to HH, it will deflect the same for any metal.

- Carl

Thanks Carl

Just put together Rev C version, been abit of a minefield so to speak getting through all the info, in the instructions and board for bits that weren`t in the instructions. and getting it to work in some fashion, so far I have a frequency generator as it doesn`t do much more than make a noise, can adjust from clicking to a pretty much flatout chirp & whistle or eeeeeeeeeeeee (you know what I mean). the thing is can`t seem to get anything registering at the coil.
The only bit of test equipment I have is a DMM, I have managed to take a reading from the coil (out/in -TX/RX) on the board. sheild has been attached to return wire which as you mentioned is strangely enough the +ve rail on the board. Readings with coil connected with DMM on the V with underscore and 3 dotted lines set at HV 1000V = 550, Set at 200V = 62 (in both cases reading on -ve/shield side was 12.23) . DMM set on the V underscored with squiggly line set at 200 was 66 on + coil side, & 26.1 on coil/shield side.

couldn`t get any response originally from coil end even from shorting coil wires together, had to put a jumper in at/from Q3 area r8 i think it was
(don`t have it here beside me) found that r35 has more effect on threshold than r31, if thats what it is, r35 will change tone from lower to high pitch squeal, where as r31 seems to do very little, the two that are side by side r2/r3 work to change the tone as does r42 or 46 (the one at the top of the board), vol works fine.

Single Coil was made from approx 27 turns of .4 wire about 10.5inDia. & another coil at about 13inDia.19turns, two wraps of insulation tape, for shielding used was fine wire about 0.1mm(real thin) wound one way then came back on itself the other way so ended up where started winding the shielding (turns spaced about 1/4 inch right the way around), covered with a further couple of wraps of tape. Made DD coil approx 12+3/4 inches wire Diameter, have not tried this one just the two others. however, as stated earlier theres no response. I haven`t a clue how to proceed.

I guess if it doesn`t work as intended, I could probably hook it up to the artificial grid point and see what happens.

Cheers
Nugget

[Unregistered]

Can`t seem to get it silent, checked some of the other older posts/threads circa2004, notably Molzar & Nick, yet not much of it seems to apply.

Going by the parts list, a couple of the resistors were mentioned twice (I put in the 1M ones first, then changed them to 100k as they were listed there too).

Checked R18, no apparent difference in adjusting it.
Output/volt at IC8 pin 5=11.55v other points 12.2
IC2(78L05) has reading of 12,12,22v at pins1,2,3 (maybe faulty part?)

Did anyone get it working first go? How about the new ones seems quite a few put them together, how many got them working to satisfaction.

Thanks
Nugget

[Unregistered]

:banghead:Thanks, guess its screwed, I`ll just trash it, this whole embarkment on this HH sort of defeated the purpose.:stupido2: Now Im depressed, what a waste of time and money. Guess Ill have to look at something else.

Oh, by the way, the other reason for the meter, regardless of discrim. or ID, would sort have or atleast partly answered the problem of more volume for the hearing impaired or what have you in one of the other threads, atleast they`ld have a bit of a visual, guess should stick with my own probs, adopt a seemingly common attitude and bugger the rest, like who really gives a flying rats ***.

Goodluck
Nugget

:stupido: :bike:

[Carl-NC]

Checked R18, no apparent difference in adjusting it. Output/volt at IC8 pin 5=11.55v other points 12.2
IC2(78L05) has reading of 12,12,22v at pins1,2,3 (maybe faulty part?)

These voltages don't make sense. Start with the power supply. Make sure you are getting +5, -5, and -5 at the outputs of IC2, IC3, and IC4. Make sure you have the DMM ground lead on ground, and not -VB. If you don't get the right voltages, then there is no point in proceeding until this is fixed.

Did anyone get it working first go? How about the new ones seems quite a few put them together, how many got them working to satisfaction.

This is not a trivial project, especially if you have no oscope. But lots of people have succeeded, even with just a DMM.

Oh, by the way, the other reason for the meter, regardless of discrim. or ID, would sort have or atleast partly answered the problem of more volume for the hearing impaired or what have you in one of the other threads, atleast they`ld have a bit of a visual

You can do that, by adding a meter to TP9. I would suggest a 50uA or 100uA meter with a series resistor.

- Carl