Un sensor de movimiento

http://modelix.com.br/

http://www.instructables.com/id/Protect-Your-Home-with-Laserbeams/
http://www.youtube.com/watch?v=CPVQaX3BK4o&feature=relatedhttp://www.youtube.com/watch?v=_21MN67h1so&feature=related pluma de estacionamiento
http://www.youtube.com/watch?v=1gjzgQXoYSc&feature=related Sensor de iluminación
http://www.robotic-lab.com/foros/viewtopic.php?f=1&t=1415This is a basic circuit diagram to make a light sensing circuit using a Light Dependent Resistor (LDR).

Shown in the video is the one for the ON when it's dark. And for the ON when it's lightsimply exchange the resitance and the LDR components.

I used a 5volt power source, and if you use 9, 12, or some other value then you will have to change the value of the resistance. The value of theresistors needed also depends on the model of the LDR you use...so you may need to experiment a bit before you are comfortable with a design. I have an improvement to the design , but it's for peoplewho show greater interest in this kind of stuff only; maby you actually want to build something...check the video comments for that.

For the circuits In the video I used:

Common parts:

V = 5Vdc..
Transistor, or "Q", was a small NPN plastic type.
LED - light emitting diode
LSR - Light Dependent Resistor (about 200Kohm dark)

ON when Light (illuminated):
R, or resistor about 10K ohmsON when Dark
R, or resistor about 400K ohms (330K to 430K)
For the improvement I mentioned, just message me.
Note that this value is different that the other circuit.

If you use a differentsupply voltage, say if higher, the value of the resistor will have to change.

When looking at the bottom of the transistor, where the leads come out, and with the flat part of it facing to the leftside: The lead at the top or upper part is called the collector (C), the lead in the middle is called the base (B) and the lower lead is the emitter (E). This is what is basically shown in the...