The There Are No Stupid Questions Thread

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.

Here is a switch connection guide.

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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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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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

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.

Hmm, that didn’t land…

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

Just trying to imagine a hybrid of lion and bat.
So scared …