I want to make home automation using Arduino. Instead of relay modules, I prepare my own relay module using relays and transistor switches, in between the Arduino and relays.
I want to make many transistor switches. Instead I planned to use IC like ULN2003A which has 7 darlington arrays that I can use as switches. They also have flyback diodes to protect from sudden spikes. (Also cheaper compared to 7 transistor switches and diodes.)
Is it a good idea to use it? Or is there a better way to solve my problem?
I need to turn on/off 220V loads using 5V DC relays which are activated by a PNP transistor switch, whose base current is provided by the output of an Arduino and collector-emitter has a separate power source to activate the relays. If I want to operate many appliances, many such transistor switches are needed. Hence I searched for a simple solution and found an IC which can act as multiple transistor switches (ULN2003A).
Is it ideal to use that in my circuit, considering power losses and other factors?