Laser Beam Alarm System with Rechargeable Battery for Laser

Step 2 The Schematics

Now before I let you start soldering your components and making your custom PCB's and stuff I advise that you prototype everything on a Bread board. It took me a very long time to dial in all the components and even longer to get them to work together because I needed to do a lot of self engineering, and also because I am unable to tell you exactly which transistor to use in the LDR and alarm unit. Sorry.

Anyway, this is the first schematic and by far the simplest. The only confusing part is choosing the correct resistor to uses with your LM317T and your chosen rechargeable battery. I will explain how to do this in the next step, its actually pretty easy.