The above explained two circuits may be built through the following steps:
Cut the general PCB to the required size.
Insert the IC first and solder its leads.
Next, insert all other associated components around the IC. With the help of the circuit schematic interlink and solder them to complete the assembly.
(Click Image to Enlarge)
For the rain sensor circuit, the sensor part is easily built by fixing two 1/8 × 1/4 brass screws over a small piece of plastic at about 5 mm apart.
Connect the sensor to the circuit using flexible wires. The sensor needs to be placed outside the house, so dimension the wire lengths accordingly.
Similarly, for the light sensor circuit, configure and dimension the LDR connections as explained above, only if an extension of the LDR position is felt necessary, otherwise it may be fitted externally over the box itself.
Enclose the circuit in a suitable plastic box, with built in battery or the power supply, appropriately allowing the sensor wires to move out of the box.
The alarm circuits using 555 timer applications presented here are just a few to mention and hopefully you may get to read many more of them in my forthcoming articles.