This achievement is best paired with the achievement "Adrenaline Rush" which is obtained for manually triggering AR Mode but instead of destroying one robot... you destroy 3 in a row. Quoting and paraphrasing TrueAchievements user "I Yova I" 's guide for that... this is best done around Act 1-6 when you first encounter the Jellyfish enemy archetype that basically spores out into some smaller units upon its death. By doing this you'll knock out two birds with one stone.
This video by YouTuber "Leo K [Rouge]" also gives a pretty good refresher on how the AR Mode works if you're a tad bit confused on timing for these things.