Remote switch tail board with FET, so no added resistance

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Lexel
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Remote switch tail board with FET, so no added resistance

Annoyed with the low output with remote pressure switches for flashlight?

I did a board with a MOSFET to eliminate the extra resistance from the external switch
size 16-17mm, for 16mm the battery holder fins need to be cut a bit

I use a MOSFET with a low gate voltage which gets full output down to 1.8V

The MOSFET is powered by a CR1225 Lithium battery with 36mAh should run easily hundreds of hours on

Aliexpress has cheap remote switches, you could dismantle for the cable and pressure switch, or one that fits your flashlight
https://www.aliexpress.com/w/wholesale-remote-pressure-switch.html

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[Sale] TA drivers Narsil or Bistro / Remote switch tail DD board with FET

Edited by: Lexel on 11/06/2017 - 13:37
maildroid
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Please forgive me as ask . What is fet ?? # newbie question

"Let your lite shine "

AlexGT
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Very Interesting, Beer And if you do a copper bypass on the spring, by how much do you think it can reduce the resistance? Maybe something to incorporate to the illuminated switches…

Good job!

pinkpanda3310
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If you do a run I’d be interested in a couple of these Love

Lexel
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maildroid wrote:
Please forgive me as ask . What is fet ?? # newbie question

for FET read this
https://en.wikipedia.org/wiki/MOSFET

AlexGT wrote:
Very Interesting, Beer And if you do a copper bypass on the spring, by how much do you think it can reduce the resistance? Maybe something to incorporate to the illuminated switches…

Good job!

The intention for this is not to replace a normal tail switch, but external switches
with a spring bypass this will be the same as with a normal tail switch, so you can run your 3000 lumens light with a remote pressure switch without smoking the switch

the external remote switch becomes basically just an e-switch, with the FET replacing the tail switch

[Reviews] Miboxer C4-12, C2-4k+6k, C2, C4 / Astrolux K1, MF01, S42, K01 / BLF Q8 / Kalrus G35, XT11GT / Nitefox UT20 / Sofirn SF36, SP35 / Imalent DM21TW / Wuben I333 / Ravemen PR1200 / CL06 lantern / Xanes headlamp

[Mods] Skilhunt H03 short / Klarus XT11GT, XT12GTS / Zebralight SC50+Imalent DM21TWcolorful anodisation

[Sale] TA drivers Narsil or Bistro / Remote switch tail DD board with FET

pilotdog68
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I always wondered why nobody had done this, but didn’t really have a reason to myself. Nice work.

My Favorite Modded Lights: X6R, S8 , X2R , M6, SP03

Major Projects:  Illuminated Tailcap, TripleDown/TripleStack Driver

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Can you make a part list for this? I mean what resistor valuse and diode and an example fet type. And then I will build some for me. Can you eliminate the button battery with a bleeder resistor or it doesn’t work without it anyway?

Lexel
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You can use a 4.2V supercapacitor, or 3.3V supercap with 3.3V LDO or a 3.7V rechargeable button cell with bleeder

But the 20 cent button cell should last for several 100 hours you push the button, and it is as expensive as the shottky diode

I will make it open source when I have tested it

The first 9 boards I ordered had a error rendering em useless

[Reviews] Miboxer C4-12, C2-4k+6k, C2, C4 / Astrolux K1, MF01, S42, K01 / BLF Q8 / Kalrus G35, XT11GT / Nitefox UT20 / Sofirn SF36, SP35 / Imalent DM21TW / Wuben I333 / Ravemen PR1200 / CL06 lantern / Xanes headlamp

[Mods] Skilhunt H03 short / Klarus XT11GT, XT12GTS / Zebralight SC50+Imalent DM21TWcolorful anodisation

[Sale] TA drivers Narsil or Bistro / Remote switch tail DD board with FET

ZozzV6
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Thank you!

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Subscribing

Tom Tom
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If you used a PFET you wouldn’t need any gate supply at-all.

And a couple of nand gates could give you a toggling on-off switch, it might need e.g. a cap. and maybe a little bleed resistor to hold up supply to the toggle, or not.

I think someone on CPF used to make these, with NFET and cell, a while ago.

But for e.g a gun torch, just direct drive through a FET in the tailcap works so well. Whether triggered by a button, or remote switch.

Lexel
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Tom Tom wrote:
If you used a PFET you wouldn’t need any gate supply at-all.

And a couple of nand gates could give you a toggling on-off switch, it might need e.g. a cap. and maybe a little bleed resistor to hold up supply to the toggle, or not.

I think someone on CPF used to make these, with NFET and cell, a while ago.

But for e.g a gun torch, just direct drive through a FET in the tailcap works so well. Whether triggered by a button, or remote switch.

You mean a P-FET should work just connecting ground to it, this one needs a bleeder probably on the main driver
just unsure if this one would need a gate resistor to positive side, which would let the main LED glow very low
I have searched for a suitable source and I think I found a few with lower resistance and working voltage down to 2V

[Reviews] Miboxer C4-12, C2-4k+6k, C2, C4 / Astrolux K1, MF01, S42, K01 / BLF Q8 / Kalrus G35, XT11GT / Nitefox UT20 / Sofirn SF36, SP35 / Imalent DM21TW / Wuben I333 / Ravemen PR1200 / CL06 lantern / Xanes headlamp

[Mods] Skilhunt H03 short / Klarus XT11GT, XT12GTS / Zebralight SC50+Imalent DM21TWcolorful anodisation

[Sale] TA drivers Narsil or Bistro / Remote switch tail DD board with FET

luminarium iaculator
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I just wan’t ready plug and play versions of this Smile

Modding is making something how you want it to be, not how it comes stock...

Old-Lumens

Tom Tom
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The gate resistor is necessary to keep the thing switched off, but it passes no current when off. It is just there to ensure the gate is discharged, any tiny leakage might mess things up. No power consumed. No LED glow.

It does work. There are good PFETS around these days, this is a standard arrangement for reverse protection or totally removing power (ignition switch) in automotive applications, and there are some great devices.

NFETs are what youngsters are trained about, and the modern logic-level ones are so impressive, compared with e.g the first IR HexFets that I helped design over 30 years ago. But PFETs have developed too, and are fit for purpose in this sort of thing. On and off. Maybe not fast PWM.

We used to worry about mobility of holes vs. electrons, but that is less of a problem these days (but electrons still move much better) Wink .

Lexel
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Tom Tom wrote:
The gate resistor is necessary to keep the thing switched off, but it passes no current when off. It is just there to ensure the gate is discharged, any tiny leakage might mess things up. No power consumed. No LED glow.

It does work. There are good PFETS around these days, this is a standard arrangement for reverse protection or totally removing power (ignition switch) in automotive applications, and there are some great devices.

NFETs are what youngsters are trained about, and the modern logic-level ones are so impressive, compared with e.g the first IR HexFets that I helped design over 30 years ago. But PFETs have developed too, and are fit for purpose in this sort of thing. On and off. Maybe not fast PWM.

We used to worry about mobility of holes vs. electrons, but that is less of a problem these days (but electrons still move much better) Wink .

I looked at good P-FETs and I found one Vishay, the thing is it costs more than the battery with holder for the N channel, also the battery increase the overall thickness of the board so it is more compatible to regular switch boards with the switch taking a few mm extra space

luminarium iaculator wrote:
I just wan’t ready plug and play versions of this Smile

I have ordered 3 remote switches
9 boards
10batteries
not ordered the Mouser parts yet
if there is demand here to buy this board please respond if you want it with switch or just the board assembly

1. luminarium iaculator
- one board?
or all parts to mod your tail cap?
size 17 or 16mm?

[Reviews] Miboxer C4-12, C2-4k+6k, C2, C4 / Astrolux K1, MF01, S42, K01 / BLF Q8 / Kalrus G35, XT11GT / Nitefox UT20 / Sofirn SF36, SP35 / Imalent DM21TW / Wuben I333 / Ravemen PR1200 / CL06 lantern / Xanes headlamp

[Mods] Skilhunt H03 short / Klarus XT11GT, XT12GTS / Zebralight SC50+Imalent DM21TWcolorful anodisation

[Sale] TA drivers Narsil or Bistro / Remote switch tail DD board with FET

DavidEF
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Cool! I have no use for this. But still cool! I’m subscribing to see where this one goes! Party

Reason is not automatic. Those who deny it cannot be conquered by it. Do not count on them. Leave them alone.
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Well I can’t remember where I posted it years ago but I made my own FET remote switch with some air wiring and random parts I had laying around. Currently on my 12-gauge pump switching an XHP50 in a C8 fed from a couple 18350s. I’ve been meaning to teach myself Eagle so I could design a neater solution, but I haven’t. So I’ll be in for a few if these turn out well. I’m actually really interested in a PFET version if it saves space as the 2S 18350s are a bit of a squeeze. Plus I’m considering boring a C8 tube to take a 21700 and need the length there too. Additionally, I’d feel more comfortable not relying on the coin cell connections in a high recoil application. Though my hack job homemade setup has done surprisingly well..

luminarium iaculator
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Lexel wrote:
luminarium iaculator wrote:
I just wan’t ready plug and play versions of this Smile

I have ordered 3 remote switches
9 boards
10batteries
not ordered the Mouser parts yet
if there is demand here to buy this board please respond if you want it with switch or just the board assembly

1. luminarium iaculator
- one board?
or all parts to mod your tail cap?
size 17 or 16mm?

Hi Smile

Sure put me in a list for one with cable… If I will like it I will order more.

I thought that 20mm boards are more standard ones? 90% of Uniquefire flashlights, Brinyte, Mitkos Supwildfires etc….

Let the reference of Omten or Kan 28 switch guides you… Flashlight who has them installed must have at least 20 mm switch board because their size is 18mm(cube) and 19-19,5 at contacts below.

But of course I am still in cause it is no problem for me to piggy back it to 20mm board Smile

Modding is making something how you want it to be, not how it comes stock...

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luminarium iaculator
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JaredM wrote:
Well I can’t remember where I posted it years ago but I made my own FET remote switch with some air wiring and random parts I had laying around. Currently on my 12-gauge pump switching an XHP50 in a C8 fed from a couple 18350s. I’ve been meaning to teach myself Eagle so I could design a neater solution, but I haven’t. So I’ll be in for a few if these turn out well. I’m actually really interested in a PFET version if it saves space as the 2S 18350s are a bit of a squeeze. Plus I’m considering boring a C8 tube to take a 21700 and need the length there too. Additionally, I’d feel more comfortable not relying on the coin cell connections in a high recoil application. Though my hack job homemade setup has done surprisingly well..

Yes… Contacts must be solid and I think it wont be problems.

How to simulate recoil? Take flashlight in one hand while holding pressure switch turned on with other hand and then take your best and hardest twitch with a hand like you’r gonna throw it to floor. Do several of “simulating throws” in a row and if flashlight will not loose a contact you have good setup.

Edit: It should not change modes either…

Modding is making something how you want it to be, not how it comes stock...

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Lexel wrote:
I will make it open source when I have tested it
BeerBeerBeer

I wanted to build this for a long time (but lack of electronic knowledge stopped me doing that).

 

Tom Tom
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I have probably misled myself, and you, about the PFET implementation, It isn’t really any different from the N version, i.e. still needs gate drive, which isn’t available at the tail, once the FET is turned on.

Sorry about that. I was mis-remembering a design for a gun torch, where the “driver”, actually just a FET, was in the head, and the remote switch hardwired into it at the head, not the tail. A PFET was used to switch the positive, it was a modified incandescent torch being used, not LED, and this seemed the easier way at the time.

I found the old CPF article where a similar method was used to replace a mechanical clickie tail switch, which were not so robust at high current in those days.

http://www.candlepowerforums.com/vb/showthread.php?296127-The-quot-FETti...

The replaceable coin cell seems the best way, but if wanting something permanently soldered in, even potted, perhaps e.g. a Panasonic VL series, recharged through a bleed resistor and some simple method to maintain the correct 3.4V.

https://industrial.panasonic.com/ww/products/batteries/primary-batteries...

https://industrial.panasonic.com/cdbs/www-data/pdf/AAA4000/AAA4000COL17.pdf

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Another application for this switch is to allow the use of longer cells in some clicks lights or as a tool in many homebrew builds. I’ll be waiting for the final parts list as I’ve too been waiting for something like this:) it’s been talked about a number of times but nothing ever really came of it. Looks like you’re making it happen. Yay!

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I’m running a boss head with 2x IMR 16340’s so probably well over 2,000 lumens. Using a stock SF tape switch and have had no issues. I would certainly be interested in looking at this for a different build I’m working on.

I’m still fairly new to BLF, hope a cut-down image of a rifle forend is allowed

have light, will travel

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DrafterDan wrote:

I’m still fairly new to BLF, hope a cut-down image of a rifle forend is allowed

TexasAce and WarhawkAWG have shooting guns in their avatar, and they are still here Big Smile
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I’m interested!

Can you put me down for a kit please?

Is there a list of remote switches for various lights around?

I thought I saw a remote switch for the Brinyte B158 but can’t locate it on GearBest right now.

Lazy-R-us

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I have ordered some switches that can be fitted in tailcaps, so you can convert the normal one to remote

[Reviews] Miboxer C4-12, C2-4k+6k, C2, C4 / Astrolux K1, MF01, S42, K01 / BLF Q8 / Kalrus G35, XT11GT / Nitefox UT20 / Sofirn SF36, SP35 / Imalent DM21TW / Wuben I333 / Ravemen PR1200 / CL06 lantern / Xanes headlamp

[Mods] Skilhunt H03 short / Klarus XT11GT, XT12GTS / Zebralight SC50+Imalent DM21TWcolorful anodisation

[Sale] TA drivers Narsil or Bistro / Remote switch tail DD board with FET

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Wonder how much resistance it would lower if u make a battery free (the coin battery) remote FET switch.

Like the remote switch is connected to the flashlight AND the FET.

Doesn’t current like to flow where there is least resistance?

Like when you press the switch the current flows thru the remote switch to the flashlight but at the same time activate the FET in the tailcap so the current flows thru there to the flashlight and this are lowering the resistance?

.

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EagleShield wrote:
Wonder how much resistance it would lower if u make a battery free (the coin battery) remote FET switch.

Like the remote switch is connected to the flashlight AND the FET.

Doesn’t current like to flow where there is least resistance?

Like when you press the switch the current flows thru the remote switch to the flashlight but at the same time activate the FET in the tailcap so the current flows thru there to the flashlight and this are lowering the resistance?

.


The FET IS the switch for the flashlight, in this case. The ‘remote’ switch activating the FET is so that the total current of the flashlight doesn’t have to travel through the tiny wires of the ‘remote’ switch. It’s like having a relay for the ignition switch in your automobile so that the full starting current for the car doesn’t have to flow through the tiny wires of the ignition switch.

Reason is not automatic. Those who deny it cannot be conquered by it. Do not count on them. Leave them alone.
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Lexel
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you have to use a coin battery to activate the MOSFET,
you may choose a rechargeable one or super capacitor with a bleeder on driver, but a 25 cent battery will last for over 100 main battery cycles at high level output and 10 years

If you want a coin cell free tail FET variant you need an additional wire from the driver to the tail

the external remote switch has only the coin cell current flowing through it

It is possible to mod the tail cap and board to have a conventional switch and the external switch

[Reviews] Miboxer C4-12, C2-4k+6k, C2, C4 / Astrolux K1, MF01, S42, K01 / BLF Q8 / Kalrus G35, XT11GT / Nitefox UT20 / Sofirn SF36, SP35 / Imalent DM21TW / Wuben I333 / Ravemen PR1200 / CL06 lantern / Xanes headlamp

[Mods] Skilhunt H03 short / Klarus XT11GT, XT12GTS / Zebralight SC50+Imalent DM21TWcolorful anodisation

[Sale] TA drivers Narsil or Bistro / Remote switch tail DD board with FET

EagleShield
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Lexel wrote:
If you want a coin cell free tail FET variant you need an additional wire from the driver to the tail

Yeah. I don’t really know how I was thinking, but since I’m not a electrician the idea was great in my head.

My idea was to use the cells in the flashlight to power the FET since the remote switch is powering the flashlight also and it could steal some of the current to activate the FET.
And if the FET gets broken the flashlight would still shine but with the extra resistance from the remote switch.
Like the FET is connected in parallel before the remote switch.

Thinking about its still feels like a good idea but since I’m not an electrician I calculate my idea to be 99% wrong since I don’t know how those FETs work.

Lexel
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also another member said, you could use a P-channel FET without battery

the problem is you can switch the light on, but then you have not a positive potential to switch it off again

the resistance of the FET is 4-5mOhms at 2.4-3V, so probably less than a conventional switch, I see no problem add a normal switch in the tail and connect it to the 2 pads for remote switch and use the light that way
you will need 3 mm additional length in the tail cap assembly to make it fit

I received the FETS and battery holders today, but still waiting on the boards

[Reviews] Miboxer C4-12, C2-4k+6k, C2, C4 / Astrolux K1, MF01, S42, K01 / BLF Q8 / Kalrus G35, XT11GT / Nitefox UT20 / Sofirn SF36, SP35 / Imalent DM21TW / Wuben I333 / Ravemen PR1200 / CL06 lantern / Xanes headlamp

[Mods] Skilhunt H03 short / Klarus XT11GT, XT12GTS / Zebralight SC50+Imalent DM21TWcolorful anodisation

[Sale] TA drivers Narsil or Bistro / Remote switch tail DD board with FET

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