15A tailcap controller, multimode pwm, piezo/magnetic/clicky, feeler thread

[DIWdiver]

I'm thinking of building a new board. It would be an interface from various switch types to a load up to 10A (20A or more with heatsink)
Some of its potential uses are:
- DIY piezo switches using a cheap piezo element instead of an expensive switch
- latching circuit for piezo switches
- single and multi-mode hall interfaces
- high current PWM driver for any switch type

I'm sure forum members will come up with many other uses.

The hardware would have the following features:
- Interfacing with 1-3 switches. Switch types could be piezo, reed, mechanical, or hall effect.
- three hall sensors can be mounted on board for multi-mode rotary magnetic switch
- no heatsink required for supply voltages above 2.5V, currents to 10A
- with minimal heatsinking 15A, could go to 20A or so with better heatsink
- Switch a load to ground (FET between load and ground)
- 15 to 50 uA maximum quiescent current, depending on configuration (hall sensors are about 10 uA each)
- Quiescent current can be reduced to a few uA (FET leakage) by disconnecting power supply with a low current switch
- sized to fit in the spring groove of a Mag-D tailcap, can be ground to 1" (25.4mm) diameter
- with a Mag-C spring and insulating ring, can be installed in Mag-D with NO WIRING
- all components on one side of board. Only 0.15" (3.8mm) thick
- supply voltage 2.0V to 16V (lower and higher voltage ranges are possible)
- 120 Hz PWM dimming, 0-100% output, but gets non-linear below 3-4%, max 95% DC with no power connection
- Microchip PIC16F685 processor
- schematics and parts list provided for those who want to work on UI
- can be fitted with in-circuit programming connector
- possible to build a USB or RS-232 adapter for programming

The UI is limited only by the imagination, but I am thinking to offer the following:
Single switch:
- single mode
- three modes, hi-med-low-off
- smooth dimming, touch for on/off, hold for up/down.
Three switch:
- primarily intended for rotary switch with hall sensors on board
- can be cycled in either direction
- three modes, high-med-low-off
- four modes, high-med-low-moonlight-off

I haven't yet decided whether I would release source code for everything, but some basic working UI would be released.

Pricing would be $20-30 USD.

Please reply with interest, comments, needs, and desires.

Don

 

[350xfire]

Reed and piezo interested!

 

[lucca brassi]

- softstart

-I like to have options of wet contacts or thermal shut down

( in night dive I have full power in water , when I rise myself from water
(boat or beach with bulky stones - have enough troubles to find way out from water ; keep balance,.... )
circuit should detect coming out of water and protect led from over heating ... but could still run led for example at 10-20% to have minimal light.

It is nice to made such swiss army knife circuit for all purposes , but I think you have some troubles with space and more important wiringor have different modules which directly fit modular like http://pcb-components.de/index.php?...product_id=97&option=com_virtuemart&Itemid=64

Wish you luck!

 

[DIWdiver]

- softstart

-I like to have options of wet contacts or thermal shut down

...

It is nice to made such swiss army knife circuit for all purposes , but I think you have some troubles with space and more important wiring...

Wish you luck!

Softstart is possible, since there is a processor with PWM capability, just has to be programmed into the UI.

I forgot to mention that there are thermistors for both the onboard FET and for the LED. The one for the LED must be wired to the module from wherever the thermistor is attached. So thermal protection is available.

With a resistor change the remote thermistor contact could be used for wet contacts. The UI would have to be changed.

The board would be offered with 0, 1, or 3 hall sensors. If all 3 hall sensors are installed, you cannot use the other switch types.

I've also completed the circuit board layout, so I'm pretty confident everything will fit! Wiring will be an issue in some cases. In other cases, like incans with no remote thermistor, there will be no wiring to do!

I think the biggest problem will be managing the UI with all the options.

The only question is whether it's worth spending the time to write the UI and the money to build some.

Don

 

[wquiles]

Very cool! I just got proto boards for a somewhat similar design, also one inch diameter, but using an Atmel processor and using 7 on board Hall Efect sensors, so it is awesome to see somebody else thinking alike.

I honestly feel your idea/design is a great idea, and I also feel these is a real need for this type of switch/controller, so I am very very encouraged and happy to see another fellow EE working on this type of designs :wave:

Will

 

[gav6280]

3 Mode
Soft Start
Piezo Latching
Boost Driver
Output Power selection from 1A to 5A so could drive SST

Low voltage flashing warning, and Thermal protection dropping the power to a low setting, the light must never just turn off. I would favour reliability over efficiency as it wouldn't be good if your 200yds into a big wreck and your light says NO!

 

[DIWdiver]

Must have had a brain fart. I actually meant to start this thread in the Homemade and Modified forum, as it has applications far beyond dive lights. Maybe a mod could move it there, pretty please?

Don

 

[wquiles]

Must have had a brain fart. I actually meant to start this thread in the Homemade and Modified forum, as it has applications far beyond dive lights. Maybe a mod could move it there, pretty please?

Don

Good idea. Your board/project has a wide variety of uses, and folks with LED/incandescent bulb projects will be delighted to have it available. I feel the features vs price point you have is unbeatable :thumbsup:

You will also likely get a lot more feedback/suggestions on features since that is one of the most active subforums. Just sent a PM to David (DM51 - one of our moderators), and he will move it over

Will

 

[baywatch106]

I would buy one

 

[kubi]

Is it only me who would go for a simple but robust solution? Do not implement 3-5 current levels, blinking and fancy stuff.
I'd just overdimension the battery pack to be enough for 1.5-2 hours with the highest output to be on the safe side.

If you are willing to dive in a cave and spend down 2-3 days you will need professional light anyway.

 

[DM51]

Must have had a brain fart. I actually meant to start this thread in the Homemade and Modified forum, as it has applications far beyond dive lights. Maybe a mod could move it there, pretty please?

Don

PM also received - moving it now...

 

[ma_sha1]

Can you make it work with mag switch?

only Kai domain has a PWM board that dont need momentary mod, max 2.8A.

3 mode, 15 or 20A no need for momentary mod, it'll be a god send, I need 5-10.

 

[DIWdiver]

Can you make it work with mag switch?

only Kai domain has a PWM board that dont need momentary mod, max 2.8A.

3 mode, 15 or 20A no need for momentary mod, it'll be a god send, I need 5-10.

When you say 'mag switch' do you mean the standard stock switch that comes in a Mag-Lite? If so, then you're in luck! Except that they aren't available yet.

The UI could be offered to work with either the click-on, click-off type switch that's standard in the Mag, or with momentary switches that are available in other products.

 

[Aircraft800]

Keeping my eye on this thread, sounds like a great idea!

 

[DIWdiver]

Is it only me who would go for a simple but robust solution? Do not implement 3-5 current levels, blinking and fancy stuff.
I'd just overdimension the battery pack to be enough for 1.5-2 hours with the highest output to be on the safe side.

If you are willing to dive in a cave and spend down 2-3 days you will need professional light anyway.

[Note: this thread was originally posted in the Dive Lighting forum]
If all you want is on and off, maybe this controller is overkill. Do you want or need some features that can't be had from a simple FET/reed assembly?

 

[b-bassett]

is there any progrss on this?

iv got a few housings with piezo's already installed, could do with a driver/latch circuit to finish them off

 

[DIWdiver]

Actually, it didn't sound like there was a lot of interest, so I never pursued it. You could have a look at George's one at TaskLed.

Don

 

[b-bassett]

i thought that might be the case,

iv looked at george's drivers before, but that would require a seperate latching circuit to be able to use a standard piezo switch.

 

[DIWdiver]

iv looked at george's drivers before, but that would require a seperate latching circuit to be able to use a standard piezo switch.

Yeah, I forgot that. Pity, as piezos are pretty cool!

 

[DIWdiver]

Okay, I just ordered a few boards. It will take a while for them to arrive from China, and a while after that before I'm ready to release the first boards. But we're on the way!

D