Laser Burglar Alarm -- Need Help

[Anonymous321]

I was worried you were gone there for a sec, even though you were online.

 

[john1]

can you tell me what the blue drawings are under the springs .....

Or is there really nothing there ... ?

 

[Anonymous321]

can you tell me what the blue drawings are under the springs .....

Or is there really nothing there ... ?

There are blue lines connecting springs. But those are just labels that were part of the box. You can ignore them. The labels mean nothing.

 

[john1]

sorry to keep you,

 

[Anonymous321]

It's absolutely ok. I just hope that we will be able to accomplish something here. My heart's going to be pumping at 10beats/second until this whole ordeal is over.

 

[john1]

Okay, so there arent components and stuff underneath, its just labels on the box.

The transistor in that last pic,
cant quite see which leg goes where ....

 

[john1]

I take it that its placed as per the blue drawing , yes ?

 

[Anonymous321]

Okay, so there arent components and stuff underneath, its just labels on the box.

The transistor in that last pic,
cant quite see which leg goes where ....

The spring where the red wire goes down to the -ve of 9V is the emitter. The spring where the red wire goes to the -ve of the siren is the collector. The other silver thing going up to the spring with no red wire coming/going from it is the base.

 

[Anonymous321]

I take it that its placed as per the blue drawing , yes ?

Only the transistor and the 9V battery clip are placed according to the labels on the box. The siren (and the wires coming to it) are in the resistors section.

 

[john1]

Okay.
stick your voltmeter across the siren connections,
and connect the battery briefly, then disconnect the battery.

Any siren sound ?
Any voltage show on the meter ?

 

[john1]

Just to check,
the transistor is the NPN type, yes ?

 

[Anonymous321]

Okay.
stick your voltmeter across the siren connections,
and connect the battery briefly, then disconnect the battery.

Any siren sound ?
Any voltage show on the meter ?

No siren. No voltage.

 

[Anonymous321]

Just to check,
the transistor is the NPN type, yes ?

Yes, it is. I'm a little afraid that it may be busted from so much previous use. So I might just pluck in another one.

 

[Anonymous321]

Is everything going according to plan?

 

[john1]

dont change anything,
its fine

 

[Anonymous321]

no, dont change anything

Ok, I won't. Oh ok.

 

[john1]

could you now pick a resistor, around thirty K please.

 

[john1]

Ha,
my last post crossed with yours,
and i thought for a minute you were going to pull it apart!

When i edited, i saw you noted my post before i edited !

 

[Anonymous321]

could you now pick a resistor, around thirty K please.

The closest one I have is 33k. Should it be 1/4 or 1/8 watt?

 

[Anonymous321]

Ha,
my last post crossed with yours,
and i thought for a minute you were going to pull it apart!

When i edited, i saw you noted my post before i edited !

Haha yeah. Instant messaging.