Making Spacebar Follow A Keystroke Pattern????? Add-in???

I am using a bar code gun to enter numbers. There are two bar codes on each item that I am scanning requiring two columns for each item. Right now I squeeze the trigger and the number pops up into the currently active cell. Then I use the arrow key to move over one cell and squeeze the trigger for the next number. Then Down arrow following with a left arrow to move the highlighted cell down one line back to the first column. Kind of inefficient because although repetitive there is room for errors on my part.

Is there a way to make it that every time I press the space bar or some other key that excel highlights a cell following my desired pattern? At least for the time that I am using the bar code gun? Making it so pressing the space bar would advance the selected cell over, then down and left, then over, then down and left, alternating with each press following that pattern ad infinitum. I have to scan hundreds of these babies.

Would this be difficult? I’m not the programming type. Any help would be greatly appreciated. At least I no longer have to manually type each number in. That was a real bummer.