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I'm new to electronics, I understand most of this PCB, but the two marked components are a mistery to me, and I can't find their names.

The blue one is some kind of switch for the LED, as you can see from the top view. But when i cap it it just keeps the LED always on, and not only when the sensor activates (the sensor had this functionality before).

The red one I have no clue what it is, or what it does, it just says TAMP on the side.

Any clues? I have little to no idea what I'm doing.

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  • \$\begingroup\$ 0.1" Header or male connector and jumper, the other is a switch. They both switch current on and off \$\endgroup\$
    – Voltage Spike
    Jun 14, 2017 at 4:31

1 Answer 1

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The blue circled item is a jumper plug to fit onto the two pins - usually 0.1" spacing. They are often used to enable or disable some configuration option on installation. They are common on computer boards etc. "J1" stands for jumper 1.

The red circled TAMP component is a tamper detection switch to alarm if the unit is opened. I'd guess the front cover holds it in the depressed position. You've triggered it! Run!


Any idea of how to make the LED on when it's supposed to?

I imagine that on power-up the LED should blink when motion is detected.

When I first opened the cap was in one of the pins instead of both of them. Is that allowed?

The jumper is usually turned sideways on one pin rather than discarded so that it's there if needed later. The jumper may be to switch between two sensitivities or maybe two modes of operation - latch the alarm on if motion is detected or turn it on only during motion, for example.

Also, if I press the tampering again it should work?

I would expect that the tamper switch is in series with the normally-closed relay contact. If either of them goes open circuit the alarm circuit is interrupted and the master panel should give an appropriate response.

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  • \$\begingroup\$ Guess I'm going to jail now, you see kids? That's what you get when you mess with electronics. \$\endgroup\$
    – undefined
    Jun 13, 2017 at 22:37
  • \$\begingroup\$ In all seriousness thank you, any idea of how to make the LED on when it's supossed to? When I first opened the cap was in one of the pins instead of both of them. Is that allowed? Also, if I press the tampering again it should work? Thanks. \$\endgroup\$
    – undefined
    Jun 13, 2017 at 22:38
  • \$\begingroup\$ See the update. \$\endgroup\$
    – Transistor
    Jun 13, 2017 at 22:49
  • \$\begingroup\$ I've powered off, pressed the tamper switch, with the LED on, and it stays on even when I'm not moving, it's weird. \$\endgroup\$
    – undefined
    Jun 13, 2017 at 22:52
  • \$\begingroup\$ Try covering the sensor with aluminium foil (which is opaque to infra-red) and see if it will go off. Speaking of which - it's past bedtime in Ireland. Good night. \$\endgroup\$
    – Transistor
    Jun 13, 2017 at 22:57

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