Vallon VMH3CS Mine Detector

[Ferric Toes]

I've got the bug to purchase another Vallon and noticed some units still available from the UK EBay site although they do look a bit ratty.

So that is the plan but wondering if anyone else has purchased a Vallon from this latest seller and if so are the units ok electronically?

Given, I'll be re housing I'm not fussed about appearance.

Brian

See my PM.

Eric.

[Mdtoday]

I've got the bug to purchase another Vallon and noticed some units still available from the UK EBay site although they do look a bit ratty.
Basically, I'm looking to design a dual purpose rod / hip mounted enclosure in the smallest footprint I can and include LI batteries, Bluetooth and design an audio mod to reduce the frequency of the sound.
The plan is also to either bypass or blank the audio output when the confidence beep occurs as just dividing the frequency by 2 gives a horrible sound. So bypassing or routing the original confidence beep around the divider circuit and blanking the divider input during that same period will still provide the original confidence beep/s but also allow the new divide by X sound.

So so that is the plan but wondering if anyone else has purchased a Vallon from this latest seller and if so are the units ok electronically?

Given, I'll be re housing I'm not fussed about appearance.

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

Eric,

Maybe a good idea to check if keypad inputs to processor have ESD protection if wiring off board.
One would hope there is some form but it's hard to tell looking at the pcb in my unit.

Brian

[Mdtoday]

All attachments are OK now.

Nice job, thank you.

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

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]

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

[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.

[chevesne]

All attachments are OK now.

Nice job, thank you.

[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

[Mdtoday]

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




Brian

[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

[Carolina]

Same here. Contact administrator.

[kingswood]

I get invalid attachment message

Me too on those pics

[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]

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