I also make my own dishwasher detergent.
This one is SUPER easy!
1 part baking soda
1 part Borax
I usually mix a cup of each in a little gladware container, mixing it with my hands.
Use 1 T. in the detergent dispenser of your dishwasher.
I also use vinegar in the rinse-aid compartment.
Cheap and easy!!