Microprocess monitoring of HF 9 function MD

Some pictures of adding a PIC chip, display and firmware to monitor the HF 9 function detector.

After many hours with a storage oscilloscope and the testpoints provided on the PCB of the HF detector.

Powers up, scans for frequency of the coil
All timing controlled by one of the PIC's internal 12Mhz timers (48Mhz PIC chip), resolution is 83ns or 5.48 clocks/degree of phase shift.
First pic shows the average  HZ found (6079) and the min/max counts detected in 12k cycles (1973/1976)

Second pic shows display while live monitoring, there are no algorithms for auto discrimination. This display shows
Top row: max voltage deviation and phase shift and GB voltage
Bottom row: Current voltage, phase shift and GB phase shift
Voltage is in ADC counts, 0 to 1023.
Three buttons, one for clear max's (min's) found, one for menu selection, one for set ground balance (GB)

Current menu's provide for voltage delta to trigger, phase shift delta to trigger. Much more planned.

Third pic shows side view. I threaded 4 wires to a 4p4c jack out of the unit.

Fourth pic shows bottom view. Micro mounted to the sliding battery door.

The micro can be attached to USB for flash program updates (many of those going on currently).

All cobbled together from my spare parts box, including display (An orbital digital 16x2 display that provides for key scanning).

You may ask why or offer advice to buy a full unit. My comment is best way to learn a new thing is to do. Now when I read all the manuals about the dream machines I have a clue of what it takes to do the features they provide, and all it cost was $40, a well stocked spare parts box and a LOT of my time :-)

Thanks for your time!

Gene



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http://www.thunting.com/smf/index.php/topic,45695.msg248181.html#msg248181

 So how does it go out in the field? It looks and sounds impressive.

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Been working the firmware. A good soaking rain followed by mist and fog showed me some 'issues' in use :-)
It is very  dependent on operator currently. Provides detected zero crossing phase shift to <0.2degrees (sub-sampled 200X per 'sample' and averaged) and return signal amplitude (resolution 5.3mv after amplification, 0.41mv prior sampled and averaged 100X sub-sample's per 'sample'). Each sub-sample being 164us, 1974 ticks of the 12Mhz clock.

Basically an all metal mode detection with operator providing the intelligence currently based on readouts. A run through my yard (about an acre+) with a backyard an old farm field that was turned residential 55+ years ago has provided a few surprises (nothing of real interest but a variety of items, many ferrous, not dug). Never knew I had permanent ground mounts for a badminton set, even after living there 20 years. Iron spikes, pull tabs and aluminum bottle caps around the horseshoe pit areas), wads of aluminum that make no sense, totally corroded wads of crumpled sheet metal, coins (though no silver which surprises me based on age of house). Have not done a run through the local state park with the new firmware yet (an OLD state park near Philly with required permit).

The basic 'logic' voltage of the HF 9 function is 5.47V and the coil drive voltage is (on mine) 6079hz (6075hz through 6082hz, mostly 6079hz average when 12k samples taken 12 seconds after power up by the firmware) with an 8V+ swing with fresh 6X AA batteries.
The 5.47V is tapped at the discriminator/All metal/Audio switch. Switch must be in discriminator mode to power the PIC and display. Of course other 'logic' power tap points available.

The TX is tapped at TP1, the RX is tapped at TP3 of the unit. There are a total of 9 TP's. TP 6 though 9 are after detection.
TP 1 is TX to coil
TP 2 is RX shifted 90deg ( or non shifted, see TP 3 next)
TP 3 is RX (or 90deg shifted, do not have unit available right now).
TP 4 and 5 are 'logic' level of TX output and selectors B and C of a 4053.

I tap at TP-1 and TP-3.

Gene


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http://www.thunting.com/smf/index.php/topic,45695.msg248749.html#msg248749

		Quote:			Posted by GoldDigger1950
	After that, it's a project done.

Yep and then you start looking for a new one  :

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http://www.thunting.com/smf/index.php/topic,45695.msg248823.html#msg248823

Xavier

Sure looks like you have been quite busy...well done to you

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http://www.thunting.com/smf/index.php/topic,45695.msg248876.html#msg248876

Xavier