Magnetic swithces for lights

[bevansmw]

Here's a picture of the driver board of the Cree MC-E diving light that is switched by a rotating magnet on the body. I don't understand circuit boards but perhaps you can. I don't see any reed switches. Someone said it was just switched with FET's.

In case this helps, here is the picture:

Is this the DX $95 light? Can't really tell much from the bottom of the PCB. So all of the electronics for this light are in the reflector & PCB on the pill?

 

[gcbryan]

Is this the DX $95 light? Can't really tell much from the bottom of the PCB. So all of the electronics for this light are in the reflector & PCB on the pill?

Yes. The reflector has a copper heatsink attached and at the base of that is the PCB. I don't know how any of that comes apart assuming the copper has some hollow space in it for components. I guess the PCB is soldered to the copper and the reflector/copper connection seems to be glued but perhaps it's just a press fit.

 

[adm3745]

the reflector unscrews from the copper pill. The driver is just conected by those two solders. IT has what looks to be 4 hall effect switches spaced every 90 degrees. I would really like a very basic circuit for this light..

 

[gcbryan]

the reflector unscrews from the copper pill. The driver is just conected by those two solders. IT has what looks to be 4 hall effect switches spaced every 90 degrees. I would really like a very basic circuit for this light..

Thanks for that info in case I need to take things apart one day.

I'd love to find more lights with this setup (minus the external heat fins and scalloped bezel).

 

[lucca brassi]

@DIW diver

IP67 means it is waterproof to 1m depth. Most divers go deeper than that . I'm not saying these won't work, just that they aren't designed for this application.

Agree - but people there uses only 5% of all switches (with exception of reed switch) that are rated IP68 or even IP69 (conditionally).

There is also a problem with all pushbutton switches that at some depth, the water pressure will activate them, and you can no longer control the light. For some switches this may occur at a depth far greater than the light will ever see, but I have heard of case where it happened at recreational depths. It might be a problem if the switch activates with little force.

Not always - depends of some conditions like air behind switch which can not compensate pressure because it is compressible. Problem is here with switch like piezo- deeperyou go , more more pressure you got. But piezo not activates on uniform pressure but on momentary pressure (look on piezo effect need - pulse force)

In that case of ELOBAU there is no air because switch itself it is potted in the plastic , which it is screwed in to the enclosure. Push button which contains magnet potted in to the plastics (to prevent corossion ) it is surrounded with water - so there is no real pressure depended from deepth ( just your force and counteracting force from spring) .

I have forgot - look only switches withoud led. IP67 can also mean that there is no additional washers for deeper tightness but I think that can be DIY solved.

But as I have said -I agree IP67 means that they aren't designed for deep submergion .

 

[wes_wall]

The pic of the printed circuit shows very little. It appears the center dot is what the battery contacts while the outer ring is for the ground (earth in the UK). The reverse of the green circuit has the switching business on it....I guess.
There is a Yahoo web site dedicated to HID dive lights. You'll have to sign up, but there is a schematic on there by Laslo that shows how to make a reed/MOSFET.
I have spent hours searching for a reed switch to contain the power (high enough amp rating.) As we say in the South "there ain't none."
I do have an old Darrell-Allan Dive light (as a collector piece) that uses a reed for the switch. It is a big reed, and carries all the power. It is rather crude, but pretty cool for the time.
I agree that magnetics is the way to go because there are no penetrations. If I can, I'll post pictures of my magnetic switch made from the schematic on the HID light forum.

 

[DIWdiver]

...I don't understand circuit boards but perhaps you can...

Well, I design circuit boards for a living, and without seeing the other side of that one, there's no telling what's on it. It could easily be a reed switch, an FET, and two resistors, plus the LED, which is all it takes for direct drive. Next to the LED, the reed switch would be the largest part.

Of course it could be vastly more complex. My prototype light has 20+ components on a 1.25" diameter board, including three hall effect sensors. It does current regulation, five-step dimming, and could be made to do other modes as well, using a magnet ring outside the body.

D

 

[DIWdiver]

There is a Yahoo web site dedicated to HID dive lights. You'll have to sign up, but there is a schematic on there by Laslo that shows how to make a reed/MOSFET.
I have spent hours searching for a reed switch to contain the power (high enough amp rating.) As we say in the South "there ain't none."

Here's a link to a reed switch that can handle 3A. Do you need more than that? It is pretty big though. I have no idea what it takes to activate it. The one that takes less field to activate it is not a stocking product.
Digi-Key - HE509-ND (Manufacturer - DRR-129 47-68)

Here's one that has screw terminals and looks a little more rugged, comes with its own magnet.
507-382I AMSECO Magnetic / Reed Switches

Seems to me like there were diagrams for reed/FET circuits on candlepower forums, which you can browse without signing up. If you need, I can design one for you in a few minutes. Just tell me the battery voltage and lamp current you want.

D

 

[adm3745]

I'm a little ashamed at my circuits knowledge but heres whats in the SSC P7 LED driver board from DX... It is 2 boards thick. The top board has an inductor on one side. On the other side there are 7 very small components. Maybe 2 resistors and a small IC. it has 6 pins.

The second board has 4 hall effect sensors an 8 pin IC another IC looking thing but smaller and one unkown component.
Don't know if that helps

 

[gcbryan]

Well, I design circuit boards for a living, and without seeing the other side of that one, there's no telling what's on it. It could easily be a reed switch, an FET, and two resistors, plus the LED, which is all it takes for direct drive. Next to the LED, the reed switch would be the largest part.

Of course it could be vastly more complex. My prototype light has 20+ components on a 1.25" diameter board, including three hall effect sensors. It does current regulation, five-step dimming, and could be made to do other modes as well, using a magnet ring outside the body.

D

This one has 4 modes, a magnetic ring outside the body, constant current regulation on a board about .75" diameter board. If it floods again I'll have to desolder it I guess and see what's on the other side but given the small size I doubt that I would be able to do much with it even if I could see it.

Is your prototype light finished or are you still working on it?

EDIT-I see adm3745 just posted ahead of me. That should be the same board(s) as mine and I definitely couldn't repair anything on that!