I saw this as the perfect solution.
Step 1: The Bits
I used an air freshener as the base.
Step 2: The Fix
Try and find a heavy metal washer attach the battery pack.
Close the base
Step 3: The Look
I used marker pens to colour in the panels on the freshener.
Do whats right for you.
I blocked up the hole in the tray with a rawlplug to stop the stuffing pouring out.