r/AskElectronics 18h ago

What is the best way to disable those leds?

Post image

What is the best method to disable the leds in this charging pad?

80 Upvotes

60 comments sorted by

162

u/raaneholmg 16h ago

Electrical engineer secret:

When we fuck up a prototype, we just cut the trace on the board, and if we were wrong we solder on a wire between two pads to get it back.

17

u/itsaconspiraci 9h ago

This is the best way. They are probably not needed for functionality. If they are, just replace them with regular diodes.

4

u/H00M4R 8h ago

Multilayer Prototypes 🥴

6

u/raaneholmg 8h ago

Haha, true. I have done a single project with an FPGA that required internal layers. Everything else has been low cost microcontrollers with a reasonably low pin count, so dual layer only.

110

u/broooooooce 18h ago

Electrical tape :P

6

u/Dewey_Oxberger 8h ago

This is the way. Or, painters tape if you want a tiny bit of light to shine through. Just cover them up with tape.

3

u/1stacewizard 4h ago

Came here to say that.

63

u/Alexander-Wright 17h ago

Permanently? Just snip them off.

As others have suggested, tape is a good reversible option.

You could desolder them, but would you ever find them if you wanted to put them back? Hot tip: tape to inside of the case.

10

u/I_knew_einstein 12h ago

I'd desolder them, turn them 90 degrees and solder only one side to one of the pads. Turns them off, but they can easily be found when needed.

21

u/fredlllll 15h ago

i would rather cut the traces, those can be soldered back together

1

u/hoganloaf 11h ago

Is a razors width wide enough of a cut or do you have to remove a chunk?

8

u/kumliaowongg 11h ago

That's enough at such low voltages/current.

18

u/Lasse_Bierstrom 16h ago

Find the series resistor, unsolder it, and solder it rotated/shifted on on pad for the future.

1

u/privatejerkov 12h ago

This is the way

0

u/Man_of_Culture08 8h ago

This is the way

17

u/rossxog 18h ago

Cover them with paint. Or maybe black tape.

8

u/Fritz794 16h ago

Or nail polish.

1

u/rossxog 9h ago

I thought about nail polish, but could the acetone do damage to the LEDs?

10

u/atax112 18h ago

Find the trace for them and cut it

2

u/HiItsMe01 17h ago

looks like they’re on a plane

3

u/star_blazar 11h ago

They should definitely not do electronics while flying. 😁

1

u/atax112 17h ago

Exactly, a cut in the right spot should disable them

3

u/BillBeers 15h ago

Shh don't tell them about via plating

10

u/thundafox 17h ago

It looks like they are in series and desoldering one will stop all.

2

u/gsel1127 10h ago

Looks like they’re all in parallel to me. One long trace on the anodes and all the cathodes on a ground plane.

3

u/agent_kater 9h ago

Seems more reasonable. Creating the high voltage required for series LEDs doesn't really make sense in a USB powered device.

1

u/Adversement 8h ago

If they are plain LED, such solution would not really work. The small differences between individual LED forward voltages would cause some of them to pull much more current that others.

All parallel would need individual series resistors, and I see none.

All series would need higher voltages, which can be done with suitable LED driver chip (but would be also not ideal, unless such chips are cheap as chips these days, or the circuit needed to generate the higher voltage in any case for the charging coil in the middle).

So, there is probably something a bit more hidden in plain sight. Reversible modifications are safest bets in case someone has really (cost) optimised the design.

1

u/grislyfind 7h ago

If one LED pulls more current, voltage goes up due to internal resistance, so they actually share current quite well.

1

u/dbegbie124 10h ago

This was what i was thinking as well.

3

u/Tentakurusama 16h ago

Black electrical tape.

2

u/pk6au 17h ago

Maybe just destroy one of them?

Or if you want to leave the way to restore - unsolder one of them?

2

u/FlyByPC Digital electronics 10h ago

Flush cutters.

2

u/PedroFaro1 7h ago

Just cut one track on one led and if they are all in series then happy days otherwise it could be 3 in series which means cutting another few tracks. Should be simple enough.

1

u/sparky124816 1h ago

Totally agree. Use an exacto and slice the trace at an angle, slightly peeling one side up. This way you could easily solder the traces back together if need be.

2

u/SolitaryMassacre 4h ago

They look to be in series. So removing one should turn them all off. Then if you want them back on you can just resolder it back. As someone else said, tape the removed one somewhere inside the case

2

u/Findron Digital electronics 17h ago

It seems like they are connected 4 parallel in 4 series. I would say that the best way to disable light is simply getting rid of those LED's by desoldering them. You can desolder one and see where it gets you, maybe you can turn all of them off by desoldering only four. You can also find where they are getting power from with a multimeter and desolder corresponding IC but it will only work if they have a separate voltage regulator, different from the rest of the circuit.

If you don't have tools to do this job, you can probably just take something sharp and hard to crush those LDS's, they're quite brittle. Try to get rid most of it to ensure you don't have a short circuit.

3

u/frank26080115 17h ago

buy a bottle of black nail polish to paint over them with

or paint marker? not sure if that's thick enough

or liquid electrical tape, which is black by default and quite thick

2

u/ipx-electrical 13h ago

Throw it away and plug the USB straight into the device.

1

u/tribak 18h ago

Some tweezers… tape too.

1

u/Ya-Dikobraz 16h ago

Snap them off with some pliers or similar. Not like you are ever going to use them again.

1

u/Lostdotfish 16h ago

Removing or disabling the 2 either side of the usb c port will stop the rest working by the looks of it.

Either desolder them or use a sharp craft knife to cut the trace on the usb port side of each diode.

Edit - actually they are in series all around the edge. Disable any one and they'll all turn off. I'd cut the trace somewhere away from the usb port at the top of your photo. Top left.

1

u/flatterfurz_123 16h ago

black nail polish

1

u/FM_Hikari 15h ago

If it's just the glow, use tape. Won't affect any functioning.

If you want to actually physically remove those, desolder them.

1

u/foley800 12h ago

Old secret - black electrical tape!

1

u/mgsissy 11h ago edited 11h ago

Liquid electrical tape or black RTV silicone, small tube of RTV should be less than $7, and I would use RTV over the electrical tape stuff because of its viscosity (not runny)

1

u/JohnStern42 11h ago

Black electrical tape is the easiest

1

u/jezmck 11h ago

Liquid tape

1

u/gsel1127 10h ago

Cut through that one long trace connecting them all with a razor.

1

u/Pleasant-Chipmunk-83 9h ago

If you have a soldering tip that's at least as wide as the LEDs, you can use the iron to slide them off of their pads. Aside from that, cutting traces with an x-acto knife will do it too.

1

u/S2Nice 8h ago

A dot of liquid tape over each, or go super sloppy and tape over all of them.

The people who design these things are not terribly sharp, because they ignore that many only charge when they go to bed, so this thing has a high likelihood of being used where we sleep. I don't need a bright blue nightlight right next to my head to show me the phone is charging while I try to sleep. A light should only be on when the phone isn't present.

1

u/kenmohler 7h ago

Just snip them off the board with side cutters.

1

u/Longjumping_Cut1987 6h ago

Ah, I think I recognise model. Blue lights? You can read by them... I'm afraid to admit but I created a 3d printable ring that squeezes right in and reduces intensity to a nice level. Let me know if you're interested. This is my first post, how best to share? Does Google drive work? https://drive.google.com/file/d/1YUj4FonuF4JZ_4TmiZ0eWl1URn6uOP1g/view?usp=drive_link

1

u/socalkid77 3h ago

I'd recon if you desolder one of them the rest would no longer work, it's hard to see but I believe they are all/most in series.

1

u/deadbody408 1h ago

Looks like they are all connected in a row . You should be able to remove one, and the rest will go iou

0

u/HiItsMe01 17h ago

tbh it’s a bit caveman but i’d just smack each of them in the center with a chisel

0

u/iluvnips 17h ago

Just black permie marker them, should dull them down

-1

u/kaffu_chin0 17h ago

black marker over the led

2

u/Financial_Mushroom83 17h ago

Nah this is how you make spooky purple light