Laser Tripwire

This project will create two units, a laser transmitter unit and a receiver.


For the schematic picture, I could not find the symbols for a buzzer or a switch.... So the switches and the buzzer are represented by diodes but are named accordingly.


You will need:
2 Battery packs
Wire
Laser Module
Resistors
Light Dependent Resistor
NPN Transistor (low voltage)
Buzzer

Solder Iron 
Solder
Mirror



WARNING: My computer messed up some of the photos so they might not be in the correct order or from the correct instructable. Do not rely only on the photos. They are a rough guide of what it could look like.

Step 1 The Laser

The schematic for laser unit says that you will need:
A Battery
A Switch
A Laser Module
An LED

First of all, solder the negative wire of the battery pack to one of the terminals of the switch and the negative wire from the module to the other terminal. Then solder the LED to the positive wire for the battery and the laser module and it is complete.

Comments

[schkip1973]

gday mate,

are you getting any light out of your laser? with a 3V battery the circuit shown might struggle to get light out of the diode with any current control.

ahh just re-read your instructible, the diodes are switches. :)

one option is to use a series resistor with the laser diode and use the diode spec for the rated voltage and current to select the reistor value. you might need a larger battery. eg [Vf @ 30ma] + 30mA*R = Vbatt

enjoyed the instructible, thanks

[thomas9666]

Yeah, sorry for the crappy schematic, I used free software for it.

Ok, thanks for the idea!

[schkip1973]

no worries dude. great instructible. keep em coming