Well the testing did not went according to plan but I was expecting that. The main problem is because I was planning to use LEDs for lighting up the stairs, but because of festive season they have not arrived yet. So instead of 1W LEDs I got stuck with 10W halogens. 10W might not look alot but the current it needs is ~0.8Amps where as LED would be 0.08Amps. The maximum that ULN2803A can handle on collector is 0.5Amps. So when I’ve got everything connected the lights worked half way and then the chips went dead 🙁
The solution would be to replace ULN2803A with 2x ULN2064 quad Darlington arrays as they can handle much higher currents.
I’m putting this project on hold until I get the LEDs. Hopefully it won’t be long.