I used to do this maybe a decade ago or so. Then I just started driving the actual speed limit everywhere I go and now I never have to worry about cops or care about speed traps or buy extra equipment or sign up for any apps. I just drive around where ever I want to go listening to music not even looking for cops or cameras. Totally oblivious to all of that stuff. It's really nice and takes a lot of the stress out of driving. Best part, it was totally free.