The There Are No Stupid Questions Thread

1309 posts / 0 new
Last post
Scallywag
Scallywag's picture
Offline
Last seen: 19 hours 4 min ago
Joined: 01/11/2018 - 22:23
Posts: 1903
Location: Ohio, United States

JasonWW wrote:
Scallywag wrote:

I’m also collecting the platters out of my dead spinners, for a future art project. Most of my hard drive magnets are on my fridge…

What do these magnets look like?

I’m too lazy to take and upload a picture – but I checked, and the google image search result for “hard drive magnets” is pretty representative. I have varieties from both desktop (3.5”) and notebook (2.5”) hard drives.
Lightbringer
Lightbringer's picture
Offline
Last seen: 4 hours 38 min ago
Joined: 08/30/2016 - 14:12
Posts: 14247
Location: nyc

The ones I grabbed look kinda like brake-pads.

09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

lionheart_2281
lionheart_2281's picture
Offline
Last seen: 14 hours 9 min ago
Joined: 10/25/2012 - 18:32
Posts: 3106
Location: Brisbane, Australia
Lightbringer wrote:
The ones I grabbed look kinda like brake-pads.

Yep that’s exactly what they look like

jeff51
jeff51's picture
Offline
Last seen: 1 day 18 hours ago
Joined: 03/26/2019 - 17:36
Posts: 846
Location: Middle of Texas

Here are a couple. Often the holder has bends in it and makes it less handy to play with.
You can pry the magnets off the plates, but the magnets are way brittle and I often end up breaking one when doing this.
If you want a really strong magnet to play with, seek out an old 5.25” floppy drive – one of the early ones. They have a circular magnet that was used in the motor. So strong, it’s difficult to remove one from a fridge without divine intervention.
I’ve used the HD magnets to make clasps for woodworking projects. Good for holding “stuff” in place when a third hand is needed.

All the Best,
Jeff

jeff51
jeff51's picture
Offline
Last seen: 1 day 18 hours ago
Joined: 03/26/2019 - 17:36
Posts: 846
Location: Middle of Texas

Scallywag, I’ve also been collecting HD platters. I started when clients needed a data wipe on a drive that wouldn’t spin. Pulled the platters rather than smashing or drilling.
Not sure why I started putting the platters in a drawer after hitting then with the degausser, but there I go again collection “stuff”.

Some of the platters are more silver colored. They make great first surface mirrors as they are VERY flat.
For some reason I also stared stacking old CD disks from software releases Etc. Stuck a dowel in a hunk of wood and started piling them up. About 3’ tall by now.

For those interested in harvesting HD magnets, you will need a few smaller Torx drive screwdrivers. Be sure to look under labels for hidden fasteners.
Good quality stainless steel screws and aluminum (from the chassis) for recycling if you are so inclined.
All the Best,
Jeff

Scallywag
Scallywag's picture
Offline
Last seen: 19 hours 4 min ago
Joined: 01/11/2018 - 22:23
Posts: 1903
Location: Ohio, United States

jeff51 wrote:
Scallywag, I’ve also been collecting HD platters. I started when clients needed a data wipe on a drive that wouldn’t spin. Pulled the platters rather than smashing or drilling.
Not sure why I started putting the platters in a drawer after hitting then with the degausser, but there I go again collection “stuff”.

Some of the platters are more silver colored. They make great first surface mirrors as they are VERY flat.
For some reason I also stared stacking old CD disks from software releases Etc. Stuck a dowel in a hunk of wood and started piling them up. About 3’ tall by now.

For those interested in harvesting HD magnets, you will need a few smaller Torx drive screwdrivers. Be sure to look under labels for hidden fasteners.
Good quality stainless steel screws and aluminum (from the chassis) for recycling if you are so inclined.
All the Best,
Jeff


Yup. I have one of the $25 iFixit miniature screwdriver sets (well, it was $25 when I bought it, $35 here ) and it’s all I need for the screws. Some of the labels/stickers are a bit tough on just fingernails, so I’d recommend some kind of metallic spudger tool for those. As mentioned the magnets are quite strong so have fun with ferrous-metal tools occasionally snapping over to the magnets Thumbs Up

The best platter I almost had showed significant head-crash damage. Along the inner half-inch the coating was mostly completely removed (some rings here and there remained). However, that platter technically belonged to an old employer and had to go to their secure data destruction procedures… (they drilled holes in the platters). My plan for my shiny platters is to mount them all in a frame as a cute artsy “mirror”.

That’s cool re: 5.25” floppy drives. I’m not old enough to have ever used one myself, though I’ve encountered them (and the actual floppy floppy disks) as scrap occasionally over the years.

turkeydance
turkeydance's picture
Offline
Last seen: 12 hours 36 min ago
Joined: 02/20/2020 - 18:53
Posts: 587

salvaging magnets from old tech was something we did for several years.
now, we check out the recyclers on Craig’s List when we need some more.

regarding mirror-like platters: we used the hole as an aiming device
for signaling in Cub/Boy Scouts. it was harder to do as opposed to
using a dedicated signal mirror, but it can and was done.
fragility forbid inclusion in our load-outs.

Sari33
Offline
Last seen: 28 min 11 sec ago
Joined: 07/17/2019 - 05:43
Posts: 344
Location: EU

Forgive my ignorance, it can be harm to the eyes look direct a Led driven by about 5 mA but with PWM?
the driver is AMC 4*7135.
A friend ask me if there will be eyes issues with PWM.

Scallywag
Scallywag's picture
Offline
Last seen: 19 hours 4 min ago
Joined: 01/11/2018 - 22:23
Posts: 1903
Location: Ohio, United States

Sari33 wrote:
Forgive my ignorance, it can be harm to the eyes look direct a Led driven by about 5 mA but with PWM?
the driver is AMC 4*7135.
A friend ask me if there will be eyes issues with PWM.

PWM itself will not harm eyes. However, if it’s slow enough, it can be unpleasant to see. Even disorienting, I think.
ggf31416
Offline
Last seen: 1 hour 2 min ago
Joined: 02/25/2016 - 17:38
Posts: 645
Location: Uruguay

If the driver is 4*7135 the current should be 1400mA, so it’s unlikely to be 5mA unless there are 280 of such LEDs in parallel. I guess you mean 5W.

jeff51
jeff51's picture
Offline
Last seen: 1 day 18 hours ago
Joined: 03/26/2019 - 17:36
Posts: 846
Location: Middle of Texas

I don’t think it makes any difference if the LED is PWM controlled or current controlled as far as looking at it is concerned.
Too bright is too bright no matter how you get there.
As Scallywag said, a too slow PWM coupled with a short duty cycle makes for a very unpleasant light to use in almost any circumstances.
Some lights have truly awful PWM running in the 100Hz to 300Hz range with 5% to 25% duty cycles.
One of these will cause eyestrain and headaches for me and many individuals. Yet some folks seem immune to truly awful PWM.

There are several threads about PWM that are buried in the general info category.
I made a video of the LT1 PWM charactistics and duty cycle here:
https://budgetlightforum.com/node/73356

That might help explain the relation of PWM to brightness.

And another looking at PWM vs camera shutter speed.
https://budgetlightforum.com/node/73615

All the Best,
Jeff

jeff51
jeff51's picture
Offline
Last seen: 1 day 18 hours ago
Joined: 03/26/2019 - 17:36
Posts: 846
Location: Middle of Texas

Scallywag, Here are a few of my platters. 2.5”, 3.5”, 5.25”, and Big’en out of an old IBM mainframe disk pack.


All the Best,
Jeff

Scallywag
Scallywag's picture
Offline
Last seen: 19 hours 4 min ago
Joined: 01/11/2018 - 22:23
Posts: 1903
Location: Ohio, United States

jeff51 wrote:
Scallywag, Here are a few of my platters. 2.5”, 3.5”, 5.25”, and Big’en out of an old IBM mainframe disk pack.


All the Best,
Jeff


The big one is amazing. I don’t even have any 5.25s, and I expect within a few years there won’t be any active spinners in the house anymore.
CNCman
CNCman's picture
Offline
Last seen: 12 hours 3 min ago
Joined: 04/07/2018 - 10:10
Posts: 1027
Location: Mississippi Gulf Coast

jeff51 wrote:
I don’t think it makes any difference if the LED is PWM controlled or current controlled as far as looking at it is concerned.
Too bright is too bright no matter how you get there.
As Scallywag said, a too slow PWM coupled with a short duty cycle makes for a very unpleasant light to use in almost any circumstances.
Some lights have truly awful PWM running in the 100Hz to 300Hz range with 5% to 25% duty cycles.
One of these will cause eyestrain and headaches for me and many individuals. Yet some folks seem immune to truly awful PWM.

There are several threads about PWM that are buried in the general info category.
I made a video of the LT1 PWM charactistics and duty cycle here:
https://budgetlightforum.com/node/73356

That might help explain the relation of PWM to brightness.

And another looking at PWM vs camera shutter speed.
https://budgetlightforum.com/node/73615

All the Best,
Jeff


.
Thanks Jeff Thumbs Up
I will check this out. Is there a way to improve the duty cycle time ?
.
jeff51
jeff51's picture
Offline
Last seen: 1 day 18 hours ago
Joined: 03/26/2019 - 17:36
Posts: 846
Location: Middle of Texas

CNCman,
PWM and the duty cycle is baked into the firmware.
So unless you can get hold of the code and flash the driver you are stuck with the OEM settings.
In another thread TK told me that the 5K PWM at the lowest levels was to provide enough “ on time” pulse to light the LED.
I (think) I can detect PWM into 3K realms if the conditions are right.
Total dark and spinning fan blades that I can vary the RPMs.
5K and up and I’m good.
All the Best,
Jeff

CNCman
CNCman's picture
Offline
Last seen: 12 hours 3 min ago
Joined: 04/07/2018 - 10:10
Posts: 1027
Location: Mississippi Gulf Coast

Is it possible to modify a Halogen light bulb spotlight to use a XHP 70.2 led. I am concerned the reflector is not designed correctly for a led.
A good friend uses a cheap Q beam on his early morning fishing trips in his Bay boat to navigate to open waters. I thought maybe it could be improved since he is disappointed in its output. I wanted to dig into it since my operating table is vacant. Wink

Scallywag
Scallywag's picture
Offline
Last seen: 19 hours 4 min ago
Joined: 01/11/2018 - 22:23
Posts: 1903
Location: Ohio, United States

CNCman wrote:
Is it possible to modify a Halogen light bulb spotlight to use a XHP 70.2 led. I am concerned the reflector is not designed correctly for a led.
A good friend uses a cheap Q beam on his early morning fishing trips in his Bay boat to navigate to open waters. I thought maybe it could be improved since he is disappointed in its output. I wanted to dig into it since my operating table is vacant. Wink

Yeah, most likely the reflector is not shaped correctly for an LED. Think about where the light is being emitted in each case – and therefore where the reflector’s focal point should be. For an LED, it’s almost exactly at the bottom of the parabola. For a halogen bulb, it’s going to be some distance inside the reflector.
anonymous_user
Offline
Last seen: 4 days 11 hours ago
Joined: 05/23/2019 - 21:59
Posts: 313
Location: CA, USA

I have seen several Surefire lights that include a clip that makes it go bezel up when stored in pocket. What are the practical uses for such a configuration?

I know for some small lights you can clip to your hat and use as a pseudo headlamp but what of larger lights?

Pages