Smart-Switch-5A
Smart switch 6 amperes This switch can be used with the all eletric appliances less than 6 amperes in order to save them from over and under voltage and high current, power fluctuations, etc. See the technical details below-----
Short circuit Output from current sensor is given to negative of the internal comparator of the attiny88 through the resistor network. Whenever the peak current goes above 7 amperes, interrupt is generated and we count the 5 cycles and if the current exceeds for the continuously 5 cycles, we turned off the switch. Only power off and power on can bring the switch on back.
Timing descriptions ADC ADC Channel 4 - voltage ADC Channel 5 - current ADC Clock – 1MHz 0r 1us ADC conversion time - 25 clock cycles - 25*1 = 25us
Voltage and Power
No of samples for voltage = 50 (ac input voltage positive half cycle) No of samples for current = 50
No of half cycles for power = 10
Time taken for power measurement = 10*20 = 200ms
Over Power and short circuit
Over power cut-off time – 200ms No of Surge current cycles ignored = 5 Short-Circuit current cut-off time - 100ms
Timer
Timer0 clock - 8us Timer0 count = 30, 255-30 = 225 Timer0 overflow interrupt = 2258 = 1.8ms Start-up counter = 6 Time for every start-up counter after power up = 3001.8 = 0.54sec Total delay of 5*.54 = 2.7s is given after powering up. Display updating after every = 3*.54 = 1.62sec
Electrical Working Ranges
170 < input rms voltage < 270 -------- Relay On, else Off. 0 < input rms power < 2100 ------------Relay On, else Off. Current < 9amp --------------------------Relay On, else Off.