The There Are No Stupid Questions Thread

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JasonWW
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Boaz wrote:

Why do people say “You cut yourself more with a dull knige compared to a sharp knife? 


 


One downside to me finally learning how to sharpen my knives is… I have cut myself more often and much worse . 


 


 Lets dispell this myth


It has to do with the fact that you have to apply more pressure to the blade of a dull knife in order to cut something which can lead to the blade slipping and you accidentally cutting yourself. A really sharp knife requires very little pressure to cut something.

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As Jason said, but I think it has two sides.

Yes you might ‘touch’ yourself with the blade more often and thus having the possibility to cut yourself.

But a dull knife won’t cut your skin as easy as a sharp knife.

So yes, with a dull knife you increase the possibility that the edge of the blade touches your skin when handling a knife.
But with a sharp knife you increase the possibility to cut yourself when the blade touches you. Big Smile Beer

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First off, I don't use knives hard, and I'm pretty careful with them.

I have rarely cut myself with sharp knives.

I have never cut myself with dull knives.

myth_busted

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I have done a lot of dry walling. Use a utility knife all day everyday. Cutting yourself does involve how much pressure applied but also presence of mind and a little luck. Knock on wood, never cut myself scoring drywall. Bought a knife once. First time I opened it I cut myself. Never liked that knife.

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Boaz wrote:
Why do people say “You cut yourself more with a dull knige compared to a sharp knife?

‘Cause then you gotta press harder on the knife, risk having it slip, and cut your arm off at the elbow.

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JasonWW wrote:
vinte77 wrote:
Can anyone tell me how to find common ground on a driver?

Yes, you need a multimeter of some sort. Put one probe on the outer edge of the driver which contacts the body and then use the other probe to poke around. Your looking for continuity.

If you give specifics, we can be more exact.

Specifically, I’m looking for common ground spots to wire an e-switch for the meldx driver (I know I can just PM Everett and get the answer). However, it got me thinking that I wanted to figure out a way to do it in general since I have a multimeter. I usually do my wiring for drivers looking at pictures or looking at the labels on drivers but I don’t understand more technical stuff to do more custom driver mods (I can stack chips, change out small parts on drivers, and add resistors for tail lights).

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Some friends of mine use to take people for bushcraft and wilderness life training.

As most people used to work with knives do, they went with the usual "“You cut yourself more with a dull knige compared to a sharp knife" and usually started teaching people how to sharpen their knives and tools before using them but after some time they eventually decided to remove the "really sharp" part of the sharpening lessons because  it was obvious that even with the best safety precaution people who are not used to work with cutting tools (and even some who are used to Wink ) will cut themsleves anyway and that cuts made with a not-so-sharp knife were a lot less harmfull.

 

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I have heard “a sharp blade is safer than a dull one”

Perhaps with knives it isn’t true in actual practice.

However pertaining to power tool blades (table saw, circular saw, etc.) it is definitely true. A sharp blade will handle the material feed in a predictable manner. If it is dull it will resist cutting and can lead to kick backs and other dangerous situations.

Sorry for the mini PSA. But remember you are the softest thing in the shop. Both a sharp or dull blade can hurt/injure you faster than you can say “ouch”. Using a sharp blade (in a proper manner) will reduce the chances of an incident.

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vinte77 wrote:
JasonWW wrote:
vinte77 wrote:
Can anyone tell me how to find common ground on a driver?

Yes, you need a multimeter of some sort. Put one probe on the outer edge of the driver which contacts the body and then use the other probe to poke around. Your looking for continuity.

If you give specifics, we can be more exact.

Specifically, I’m looking for common ground spots to wire an e-switch for the meldx driver (I know I can just PM Everett and get the answer). However, it got me thinking that I wanted to figure out a way to do it in general since I have a multimeter. I usually do my wiring for drivers looking at pictures or looking at the labels on drivers but I don’t understand more technical stuff to do more custom driver mods (I can stack chips, change out small parts on drivers, and add resistors for tail lights).


Here is a switch connection guide.
https://drive.google.com/file/d/0B8AQ5y6R0lboRTlUaVlhamtBNmc/view

Here is one of his drivers where you can see the circuit pretty well. We know the edge is ground because the retaining ring clamps here. So anything directly connected to the edge is also a common ground. You can probe these to confirm.

.

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vinte77
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Thanks JasonWW. So the battery ground is separate from the all the other ground spots? Does that mean that you can connect the e-switch negative wire to the ground ring as well?

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vinte77 wrote:
Thanks JasonWW. So the battery ground is separate from the all the other ground spots? Does that mean that you can connect the e-switch negative wire to the ground ring as well?

Most drivers, maybe not all, have positive battery power going straight to the led then the negative side of the led is controlled by the driver to give the correct brightness level. The driver circuits regulate how much current gets to the driver ground/flashlight body.

The negative from the battery usually goes directly into the body of the flashlight.

The MCU, or little computer brain of the flashlight, will have multiple legs or pins on it. A particular pin will be assigned to the e-switch through the software/firmware User Interface. So this pin has a small positive charge on it looking for a ground signal.

The e-switch is just a simple spring-loaded contact. When you push it you get continuity through the two wires. So one switch wire will go to the MCU pin and the other switch wire will go to any type of main body ground (any of the green areas I labeled).

When you press the switch, the small positive signal from the MCU pin connects to ground and the MCU senses this and performs it’s function (turn light on/off, etc…)

So a regular two wire switch does not care which wire is used for ground or the MCU pin.

The exception to this is when you have small LEDs on the switch PCB (lighted switch). These types of switches typically will use a single common wire to act as either a positive or negative for both the switch and the LEDs next to it. So these types of switches are polarity sensitive, meaning the correct wire needs to be going to ground and the other correct wire needs to go to the MCU and led circuits.

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Boaz wrote:

Why do people say “You cut yourself more with a dull knige compared to a sharp knife? 


 


One downside to me finally learning how to sharpen my knives is… I have cut myself more often and much worse . 


 


 Lets dispell this myth

I have several accidental cuts on both hands and arms after keeping knives razor sharp. Just carelessly closing one almost reached bone. Nothing like knowing its sharp if needed for protection. It took some experience to learn how to better handle the razor sharp ones. Now my every day carry ones are a little less than razor edge but still very sharp.

CNC & Manual Machinist. Think outside the box too long , cannot find your way back in.

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I have got a question about a 26mm FET+7135 driver (MTNElectronics). I soldered it myself and put it in a zooming light with XHP70.2. Recently I noticed that soon after turning the flashlight on the led starts to flicker slightly. I am not sure what the reason is and how I can solve it. Is the led or the driver components responsible? Any suggestions are welcome!

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Skylight wrote:

I have got a question about a 26mm FET+7135 driver (MTNElectronics). I soldered it myself and put it in a zooming light with XHP70.2. Recently I noticed that soon after turning the flashlight on the led starts to flicker slightly. I am not sure what the reason is and how I can solve it. Is the led or the driver components responsible? Any suggestions are welcome!


I would suggest you start ruling out parts to narrow the problem.

Try some different batteries. Does this fix it? If not, then the batteries are fine and we move on.

Try no tail cap and use a jumper wire instead. Does this fix it? If not, then the tail cap is fine and we move on.

Make sure the driver retaining ring is tight.

Since it’s a 70.2 and can handle direct drive, try shorting the negative side wire of the mcpcb to ground. It will go full power. Does it still flicker? If so, it’s the led. If not, then the led is fine and we move on.

If you narrow it down to the driver then you might need to ask a driver expert what component could cause it. You could go over the whole driver with hot air to make sure all your solder joints are good.

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vinte77
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JasonWW wrote:
vinte77 wrote:
Thanks JasonWW. So the battery ground is separate from the all the other ground spots? Does that mean that you can connect the e-switch negative wire to the ground ring as well?

Most drivers, maybe not all, have positive battery power going straight to the led then the negative side of the led is controlled by the driver to give the correct brightness level. The driver circuits regulate how much current gets to the driver ground/flashlight body.

The negative from the battery usually goes directly into the body of the flashlight.

The MCU, or little computer brain of the flashlight, will have multiple legs or pins on it. A particular pin will be assigned to the e-switch through the software/firmware User Interface. So this pin has a small positive charge on it looking for a ground signal.

The e-switch is just a simple spring-loaded contact. When you push it you get continuity through the two wires. So one switch wire will go to the MCU pin and the other switch wire will go to any type of main body ground (any of the green areas I labeled).

When you press the switch, the small positive signal from the MCU pin connects to ground and the MCU senses this and performs it’s function (turn light on/off, etc…)

So a regular two wire switch does not care which wire is used for ground or the MCU pin.

The exception to this is when you have small LEDs on the switch PCB (lighted switch). These types of switches typically will use a single common wire to act as either a positive or negative for both the switch and the LEDs next to it. So these types of switches are polarity sensitive, meaning the correct wire needs to be going to ground and the other correct wire needs to go to the MCU and led circuits.

Jason, thanks for your explanation. I got the everything wired up correctly now. I just need to figure out how to fit everything in the host now… Hardest thing is going to be to get the switch parts to fit.

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How do I get the reflector in optimal height to focus the LED perfectly? What do I look for in a beam or on a white wall to see if the reflector needs to be raised or lowered?

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LichtAn wrote:
How do I get the reflector in optimal height to focus the LED perfectly? What do I look for in a beam or on a white wall to see if the reflector needs to be raised or lowered?

There’s no such thing. If your looking for the highest measurements, you can adjust it for that and possibly end up with an ugly beam. It’s better to just set the height to what looks best.

There’s a lot of technical stuff you can do to adjust it, but I don’t see the point in it.

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Skylight
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JasonWW wrote:
I would suggest you start ruling out parts to narrow the problem.

Try some different batteries. Does this fix it? If not, then the batteries are fine and we move on.

Try no tail cap and use a jumper wire instead. Does this fix it? If not, then the tail cap is fine and we move on.

Make sure the driver retaining ring is tight.

Since it’s a 70.2 and can handle direct drive, try shorting the negative side wire of the mcpcb to ground. It will go full power. Does it still flicker? If so, it’s the led. If not, then the led is fine and we move on.

If you narrow it down to the driver then you might need to ask a driver expert what component could cause it. You could go over the whole driver with hot air to make sure all your solder joints are good.

Thanks JasonWW! I will follow your problem solving guide step by step. Unfortunately the flashlight has no retaining ring.

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Can I short a driver throught the AMC 7135 (lexel´s bistro FET driver)? (If there will be a contact of AMC with brass retaining ring = ground?) I don ´t completely understand functionality, in this case more like polarity of driver components.

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Anyone know off the top of their head what firmwares will work and fit on a BLF A6 FET+1 Driver with an ATtiny13?

I really need something different, but id be happy with a pretty basic clicky firmware with battcheck and no strobes.

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F.i.l.a.s wrote:
Can I short a driver throught the AMC 7135 (lexel´s bistro FET driver)? (If there will be a contact of AMC with brass retaining ring = ground?) I don ´t completely understand functionality, in this case more like polarity of driver components.

Yes, I’m pretty sure that is possible. If one 7135 is shorted by accident then there should be a minimum of 0.350 amp going through the driver and the light will not go dimmer than this.

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JasonWW
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nick779 wrote:
Anyone know off the top of their head what firmwares will work and fit on a BLF A6 FET+1 Driver with an ATtiny13?

I really need something different, but id be happy with a pretty basic clicky firmware with battcheck and no strobes.


I took a quick look at MTN E to see what he offers on that driver with ATtiny13. Besides Bistro, you can use Guppydrv Dual if you have access to it. That’s all I know, sorry.

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Hmm, I was just wondering, is there no such thing as a stupid question?

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There are no literally no stupid question, especially in this forum.

Asking a question means you are interesting in learning more, which we should cherish.

Discussion and research should be promoted to cultivate critical thinking, and encouraging being curious and asking questions is one way to do it.

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Hmm, that didn’t land…

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What is “the” best way to dispose of lion bats? (18650)

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lampliter wrote:
What is “the” best way to dispose of lion bats? (18650)
Just trying to imagine a hybrid of lion and bat.
So scared …
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Big Smile
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lampliter wrote:
What is “the” best way to dispose of lion bats? (18650)

Include them as a “free gift” with a Cometa?

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Can’t seem to find any disposal sites that will take it.

Still waiting for my cometa Big Smile

"The sun, with all those planets revolving around it and dependent on it, can still ripen a bunch of grapes as if it had nothing else in the universe to do." ~ Galileo Galilei

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