APEM Piezo Issue

[350xfire]

There is a single battery with a driver per head running at 3000ma. Drivers are wired in parallel off battery (no on/off switch other than h6flex). drivers are in ubi2 mode.

One interesting point is that on power up (where the drivers flash for a few seconds), one head flashes a few seconds longer before going steady. I'm not sure how to explain this since they're configured identically.

Interesting... I know there are some drivers out there that don't play well in parallel or series. May be disconnect one head at the driver and go dive it and see what happens as well... This way it's one battery and one driver running.

 

[350xfire]

Any suggestions for a momentary toggle design that can be used underwater. I've got a couple of Hallsw boards and was thinking about using them as a momentary switch, or even just a glass reed tube. Question I have is how easiest to make a spring loaded toggle switch - current thought is to drill a hole for some kind of sliding barrel and mill a hole into it for the sliding know. Either way, I don't think there is space in these housings to do so and I might have to leave them at fixed power and put a switch in the canister.

You can get any standard toggle type with 15/32" shaft in a momentary configuration. They are usually around $7-10. Put a boot over it and you have a sealed toggle.

 

[DIWdiver]

Shield with what?

There are lots of possibilities. You could buy some braided metal tubing that's made for that purpose, or get shielded cable that has it already inside.

You could use aluminum tape. There's even some that's made with conductive adhesive so you stick it to the body and it makes a good connection.

I've even seen people use aluminum foil, though that's normally used just for experimenting.

Basically, you want to wrap the wires with something metallic, that forms a continuous sheath around the wires and is open only at the ends where the wires come out to attach to something , then ground the shield somewhere. One way to do that is to include a bare wire inside the shield, so it makes many contacts to the shield, and gives you something you can easily solder to a ground point. The best point to use for ground is probably where the battery (-) connects to the driver. Just make sure it doesn't short something that shouldn't be shorted!

 

[georges80]

Is there ONE piezo PER h6flex or are you sharing ONE piezo with BOTH h6flex drivers?

From your pictures I assumed each head has it's own piezo, but maybe that's not the case.

cheers,
george.

 

[lucca brassi]

Piezo should have twisted pairs and mybe shield mesh from some coax cable ground to GND led driver ( but not to touch piezo enclosure ). Coax mesh can be then placed in heatshrink.

Don't know exactly but if power supply is not ''clean'' from noise should be piezo pumped and oscilate on its own ?

 

[betti154]

Is there ONE piezo PER h6flex or are you sharing ONE piezo with BOTH h6flex drivers?

From your pictures I assumed each head has it's own piezo, but maybe that's not the case.

cheers,
george.

One piezo and driver per head.

 

[betti154]

You can get any standard toggle type with 15/32" shaft in a momentary configuration. They are usually around $7-10. Put a boot over it and you have a sealed toggle.

A traditional boost style toggle is no prob. I problem should have said momentary, not toggle as I need clicks and presses.

 

[betti154]

I actually now wondering if a relatively simple exercise of changing the layout of the current carrying wires might help my cause.

At present, I've got all wires coming off the front of the board so that I can heatsink the board. With some strategically drilled holes, what I could do is send the LED +/- out the back and shorted the IN +/- wires.

This should clean up the wiring considerably and I presume this means less opportunity for interference.

It also sounds prudent to replace the piezo wires with a thin coax, though sadly I glued the piezo into the housing back and changing the wiring close enough to the piezo is going to be very difficult or impossible. Lesson for young players - don't glue piezos in!

 

[350xfire]

A traditional boost style toggle is no prob. I problem should have said momentary, not toggle as I need clicks and presses.

There is such a thing as a momentary toggle. It is spring loaded to go back to open after it is switched!

 

[betti154]

There is such a thing as a momentary toggle. It is spring loaded to go back to open after it is switched!

Not a bad idea, though still wont' solve my interference issue.

I think I'll install the capacitor and change the wiring layout, then cross my fingers!

 

[Klem]

I actually now wondering if a relatively simple exercise of changing the layout of the current carrying wires might help my cause.

, though sadly I glued the piezo into the housing back and changing the wiring close enough to the piezo is going to be very difficult or impossible. Lesson for young players - don't glue piezos in!

There are glues, and glues... If you think you might need to undo them again you can always use silicone sealant or something even less permanent like liquid gasket sealant (e.g. Silastic). As long as the piezo is held firmly in place by it's own nut then all you need do is waterproof the join. A nice tight fit with Silastic and you can 'crack' it open again later...clean up the cured residue and seal it back up again. Or, as you imply source a decent sized O ring and provided there's enough lip on the switch use that.

 

[georges80]

Try a cap across the SWA/SWB connections on the h6flex. Something in the 0.01uF to 0.1uF range should be fine. That should help a lot if it is an interference issue versus something else.

cheers,
george.

 

[betti154]

Try a cap across the SWA/SWB connections on the h6flex. Something in the 0.01uF to 0.1uF range should be fine. That should help a lot if it is an interference issue versus something else.

cheers,
george.

Will be doing so tonight.

 

[betti154]

There are glues, and glues... If you think you might need to undo them again you can always use silicone sealant or something even less permanent like liquid gasket sealant (e.g. Silastic). As long as the piezo is held firmly in place by it's own nut then all you need do is waterproof the join. A nice tight fit with Silastic and you can 'crack' it open again later...clean up the cured residue and seal it back up again. Or, as you imply source a decent sized O ring and provided there's enough lip on the switch use that.

Agree totally. I used JB Marine Weld exoxy, so the only way it's coming out now is to drill it. Thread sealant may have been a better choice since I tapped an M16 hole, though ignorantly I saw no need to use anything less than bombproof. Orings, sealants, and definitely silastic are all opportunities for failure in my experience.

I'll apply the cap on one head, and run a red LED piezo test in the other and report back progress.

 

[Klem]

I've used Silastic many times in underwater torches and it's never failed. The torch floods I have had over the years have been from O rings and cracked lenses, and one from a too thin PVC end cap flexing at depth and cracking the seal of a JB Weld'ed screw. The JB weld couldn't flex with the PVC, too hard and brittle. Flexible cured sealants like Silastic, Silicone and Sikaflex (polyeurathane) have never failed me.

 

[Flo1]

I've used Silastic many times in underwater torches and it's never failed. The torch floods I have had over the years have been from O rings and cracked lenses, and one from a too thin PVC end cap flexing at depth and cracking the seal of a JB Weld'ed screw. The JB weld couldn't flex with the PVC, too hard and brittle. Flexible cured sealants like Silastic, Silicone and Sikaflex (polyeurathane) have never failed me.

Klem, what sort of depths are you taking your lights to?

 

[Klem]

Max depth around 45M mark but mostly between 20-30M.

 

[betti154]

Max depth around 45M mark but mostly between 20-30M.

Last time I used silicone glue to seal thread into a battery canister it was fine on one dive to 15-20m. I did a subsequent dive to 90m and sprung a canister leak at 85m; lipos in the canister caused a fire and boom BOOOOOMMM - the bottom of the Sartek canister blew off, lights went out and I was left in a dark scary place. My buddy is still talking about the resulting pressure wave that came off my hip (felt like I'd been crash tackled), and the inside of the canister was all burnt up.

Now I'm not blaming this totally on the silicone, but you can't blame me for being paranoid.

 

[Klem]

Last time I used silicone glue to seal thread into a battery canister it was fine on one dive to 15-20m. I did a subsequent dive to 90m and sprung a canister leak at 85m; lipos in the canister caused a fire and boom BOOOOOMMM - the bottom of the Sartek canister blew off, lights went out and I was left in a dark scary place. My buddy is still talking about the resulting pressure wave that came off my hip (felt like I'd been crash tackled), and the inside of the canister was all burnt up.

Now I'm not blaming this totally on the silicone, but you can't blame me for being paranoid.

Wow, what a story.

I have never dived to 90m although have seen someone bounce to just over 100 on a single-tank normal air and lived to tell the tale (at the Rowley Shoals, Western Australia). Said he saw the 'Marshmallow Man' down there beckoning him to stay a while...

The several canisters with lithium batteries that I have flooded in my time have never done anything more spectacular than turn the light off. Certainly no explosions or fire. Open them up after and there's a smelly brown soup that goes straight in the bin with the rest of the torch.

Can't see how a decent silicone bead on a tight fitting thread would be the culprit but I hear what you are saying about the need to be extra careful at 90m

 

[betti154]

On a more productive note I've installed a 0.1uf capacitor in parallel with piezo signal wires on both my heads, and a mate will take them for a test dive this weekend.

Prior to installing the capacitor I ran some in air and bucket of water surface tests, and noticed power level changes. One light head was notably worse than the other in this regard (all this aligns to my underwater observations), and upon disassembly I noticed that the piezo wire on that head was 50mm longer than the more stable one. I'd say the total length of each wire is about 80mm, so that would have been up to 130mm on the longer one; keeping in mind though that the extra wire was jammed in the small cavity around the h6flex, LED +/- and battery +/-. During reassembly I took more care to position the piezo wires away from the power ones, though this may be futile given the small space.

After installing the capacitors I did not experience an unintended power level change or turn on. I also could not get either head to react to touch or static electricity, which was a earlier problem.

After running the aforementioned tests I also enabled Superlock mode on the h6Flex which worked very nicely. Fingers cross I've got a solution and will update my findings after the weekend.