Alarme a laser caseiro (DIY: Homemade Laser Alarm)

Uploaded by rjngrjng on 12.01.2010

Scenes from the movie "Ocean's Twelve"
Ever wanted to have your home protected by lasers?
Make your own system spending less!
Allright, it won't be like the movie...
... but it will be very cool too!
Making a Laser Alarm!!
Principle: a laser beam is detected by the sensor.
When someone crosses the sensor, the siren sounds.
And the chosen was...
Relay 9V; Transistor 2N3904
Diode 1N4007; LDR
Potentiometer 20 k (Set around 10 k Ohms
Potentiometer 20 k Use a multimeter for this!!)
Making of: Note the circuit diagram closely
We split some wires to facilitate the construction
We started the welding. Note that we didn't use the same
switch at the beginning, now in blue. This was only a choice.
Apparently we made a mess with the wires...
...and we did. But following the schema this have no wrong.
Connect correctly the transistor!! Remember that it's a NPN, and not a PNP.
If in doubt, ask here or for a technician. (What is not our case!!)
We used 9V DC power source.
- Turn on the laser.
- Turn on the power.
- Turn off the laser.
- Turn on the laser.
- Turn off the power.
Now we want to improve:
- Use a stronger siren!
- Turn the wires less confusing.
- Adapting properly for use in electrical current.
- Optimizing the laser (stop using a battery laser pointer)
Rafael, soon a doctor.
Daniel, soon a mechanical engineer.
Marcel, soon a psychologist.
See you! (Translated with Google help!)