The unit consists of two solar panels, one is for the timer circuit and another is for output. The timer circuit contains an Arduino which is converted into a variable timer with the help of code. It is connected to relay module. The unit also consists of rechargeable cells which are charged by solar panel. When you want to use power from them, you need to just toggle the switch.
Battery Life Calculation:
Arduino ON time: 5 seconds
Arduino OFF time: 5 min. = 300 seconds
Operating Voltage: 5V
P(avg): 5 x 2 = 10mW
Li-Ion Battery: 2100mAh
Battery Voltage: 2.4V
Power: 2100 x 2.4 = 5040mWh
Battery Life: 5040/10 = 504 Hours = 21 Days
Note: Power consumed by power booster is not calculated here.
Thus, timer circuit saves a lot energy and also saves energy by cutting power of sensors, displays, etc. In sleep mode, the power consumed by ATMEL micro controller will reduce.