Cheap and good way to feed 12v digital input

CrossRoads:
1000+ & homemade PCBs? You are a glutton for punishment!

hahaha..

please don't get me wrong..

The reason I use the homemade PCB is that there is no good estimation that how many will sell off..
Hence the keep making these 50 - 70 at a time..
It just takes half an hour to make the PCB...

And profit margins form the product is very very low..