Works Garden

Can you recommend a cat deterrent (not a dog, please….) that actaully works to keep cats out of my garden?

I have nothing against cats and wouldn’t want any harm to come to them – it’s just that they come into my garden and use it as a toilet (I have a lot of dug over earth between plants) – I just want to deter them from entering my garden but do all the advertised methods really work? Have you used or got one that is effective? If so then please let me know where to get one from.
Many thanks

clear plastic bottles of water
the idea is that animals wont foul there water supply so they see water and go elsewhere

Nobuo Uematsu’s greatest works – FFVIII: Balamb Garden (orchestral)