Vallon VMH3CS Mine Detector

[Ferric Toes]

My Vallon can detect a jean rivet at 30cm depth, but it's blind at all to this 0.3g flat gold nugget. My MiniPulsePlus can see it at 3cm though.

What are your experiences with gold nuggets and the Vallon?

I would imagine that this 0.3gm nugget is very thin as it looks about the same area as a 1gm nugget I have. At 6uS delay you are detecting it with the MPP but the Vallon is rather different. Nobody here at the moment knows what the Vallon timing is but it must be equivalent to a longer delay. My 0.3gm nugget is more spherical.

Eric.

[Mdtoday]

Hi Eric,

Thanks for that, I had a thought that it was a marking paint, I cleaned it with a diluted pcb cleaning agent without any damage.

Well, I also put the unit back together after an internal clean down, did the audio mods added the stand and tested the Bluetooth, all working Ok, no latency.
Had to add a switch for internal / external audio as I did not trust the quality of the switchable 3mm phone jacks available, works fine.

A couple of quick photos here, I will add more once I tighten everything up and give it a final clean.

Brian

[Mdtoday]

Some more photos showing Eric's audio transformer mod and an added switch for internal external audio.
the Bluetooth headphones and transmitter are V4.2 and are very low latency. Transmitter from EBay , headphones from Target Australia.
Total for BT $65



more later

Brian

[kingswood]

Great work Brian!
I like the stand, will have to follow your idea

[6666]

Some more photos showing Eric's audio transformer mod and an added switch for internal external audio.
the Bluetooth headphones and transmitter are V4.2 and are very low latency. Transmitter from EBay , headphones from Target Australia.
Total for BT $65

[ATTACH]40128[/ATTACH] [ATTACH]40129[/ATTACH]

more later

Brian

I get invalid attachment message

[kingswood]

I get invalid attachment message

Me too on those pics

[Carolina]

Same here. Contact administrator.

[Mdtoday]

Thanks Kingswood,

I had the idea after seeing some of Eric's work and started thinking about it and chatting with Eric, I set about the task.
He has been very helpful and without his input and sharing of ideas via this forum, it would have been a much longer job. So thank you Eric!
The Vallon is a very well designed and sturdy unit, I have enjoyed working on it.

I am not sure what happened to the attachments in the last post, I will try again shortly

Brian

[Mdtoday]

I have uploaded again, see how we go this time.




Brian

[Mdtoday]

For those interested. Here is the detail on Bluetooth gear used.



This image shows the machined parts for stand.

The ribs in the cover section were to hold the Bluetooth transmitter but I decided to mount it outside mainly to reduce weight..I thinned the stand section from 40 to 20mm.

Brian

[chevesne]

All attachments are OK now.

Nice job, thank you.

[Ferric Toes]

Display investigation

I didn't want to go this far, but the right hand switch was jammed solid and the whole display was in a poor state. As you can see, there were four layers to peal off before getting to the contacts. What seems to have happened is that some adhesive or sealant had run down and collected under the right hand button. It had the appearance of hot melt glue and it was difficult to prise the button off, but taking things slowly, it eventually came free and I cleaned up the contacts on the pcb.

It almost looks to me as though that button never worked as the wear marks that are visible on the other contacts are absent on the right hand one. The other interesting point is the number of contact buttons I removed. All of the buttons were in fact pairs, so there should be eight in the photo as I didn't discover the other until I used calipers to measure thickness, and after the photo was taken. Maybe this was to increase the pressure required to depress the switches as Vallon state that the detector can be used in up to six feet of water. More depth than that and the switches depress.

The existing layers of plastic (polycarbonate?) are unusable, so rebuilding the display/control unit is out of the question, but what I might try is wiring a 4 x1 keypad onto the existing contacts and rehousing the whole detector in a different way.

Eric.

[Mdtoday]

Finally cleaned and tightened everything up. Job done.
Came up OK. I will take it out on the weekend and see if I can make it dirty again.





Brian

[Mdtoday]

Hi Eric.

It looks to me like you can get away with wiring another keypad onto those pads, good quality ones will have OK debounce Chinese E bay specials will be woeful.

Brian

[Mdtoday]

All attachments are OK now.

Nice job, thank you.

Hi chevesne, thanks, I'm not sure what happened with those attachments

Brian