EEVblog Electronics Community Forum

Electronics => Repair => Topic started by: iceman on March 29, 2018, 09:06:52 pm

Title: Unknown element
Post by: iceman on March 29, 2018, 09:06:52 pm
Hello. This is my first post, so I hope I'm doing everything right :) My daughter has inline skates with LEDs that flash when she moves. There is a circuit in each one of the skates. On one skate LEDs work as expected, on another one - no light. I've inspected the circuits and found that an "element" is connected to PCB using one leg and one very thin wire. On the non-working circuit this wire is broken. There are absolutely no marks on the element nor on the PCB. I'd like to replace this element, but I have no clue what that is. Hence the question, does anyone know what that element is? It is a black cylinder, which looks like capacitor. I've attached the pictures of the working PCB and market the broken wire (broken on another PCB) with the red circle.
Title: Re: Unknown element
Post by: ataradov on March 29, 2018, 09:34:48 pm
That may be a vibration/orientation switch. I guess the thin wire is to make the sensor have only one rigid support.
Title: Re: Unknown element
Post by: iceman on March 29, 2018, 09:45:40 pm
This is an interesting idea. This element is fixed with the hot glue on the other side though. I thought that vibrations are detected using gyro on the other side of the PCB. Of course, I'm not sure that this is gyro, there are no marks on it.
Title: Re: Unknown element
Post by: ataradov on March 29, 2018, 09:49:32 pm
Try to measure continuity of that element while rotating the board in space (on a working unit). Whatever it is, I assume it just has a dry contact.
Title: Re: Unknown element
Post by: doktor pyta on March 29, 2018, 10:16:55 pm
a tilt switch?

https://www.funduinoshop.com/Tilt-switch-SW-520D (https://www.funduinoshop.com/Tilt-switch-SW-520D)
Title: Re: Unknown element
Post by: ataradov on March 29, 2018, 10:18:40 pm
a tilt switch?
That's what I was thinking. But why would it have one pin made of what seems to be an enameled wire? That just seems strange.

Although this one has asymmetric legs as well: https://www.adafruit.com/product/173 (https://www.adafruit.com/product/173) This looks like a replacement part.
Title: Re: Unknown element
Post by: Andy Watson on March 29, 2018, 10:27:34 pm
Prise-off the broken device and look for a part number. If you cannot find a part number try searching for SW 18010 on ebay - it should return something that looks very similar.
Title: Re: Unknown element
Post by: iceman on March 30, 2018, 04:14:15 pm
I cannot find the part number on the outside of that element, but indeed, when I search for SW 18010 - I get very similar parts. I'll order some of those and give them a try. Thanks!
And thanks everyone for help! As I mentioned, this was the first time I write on this forum, and I'm impressed on how fast I got help.
Title: Re: Unknown element
Post by: PA0PBZ on March 30, 2018, 05:50:43 pm
This is why there is one very thin wire:

(https://www.spiria.com/sites/default/files/blog/sw18010p.png)