Andre, a few years ago, my Mac support guy, Pat, sent me the "BikeSpike" info attached as a PDF below. (Pat is from Strasbourg, came to Canada ages back, and I've known him for probably 30 years. He also rides BMW boxer twins, as I used to, and now and then sends me info on 2-wheeled matters.) The "Bike Spike" info appeared in a BMW club journal, picked up from a Kickstarter notice for a bike safety alarm/tracer. Pat suggested that I might be interested in this, as my next bicycle (the Thorn Raven) would be expensive.
I haven't bought this device, partly because it would require that I buy a smartphone as well--there's an inexorable e-logic at work there, which makes me feel that I'm forever Feeding The Machine. Still, if one already had a smartphone, you'd be just taking advantage of its ripple effects, I guess.