I bought fobo tire pressure monitoring system for motorcycle and it is working very well... no more low tire pressure...
I just got a pair of the FOBOs, too, and I love them! I can tell you with confidence at this moment that both of my tires are properly inflated. I'm way, WAY too lazy to check my tire pressure before every ride, but now I do it! It's too easy not to. They use plain old bluetooth, so you don't have to worry about whether your phone has an ANT radio in it or anything, almost any modern phone will work fine. It's a bit over-designed if you ask me, you have to practically torch the packaging to get the product bits out, but they have to satisfy the iOS crowd as well as the Android folks, so I suppose it's to be expected. The app is also very much "let us handle that for you", but again, the iPhone people probably expect and appreciate that. It's not that hard to turn off notifications if you don't want them...or leave them on if you want it to natter at you until you get some air in your tires. They also didn't cause any vibration when I installed them without checking the tire balance, which I was a bit concerned about. No vibe problems at all, though.
Overall, I couldn't be happier with them. They're a bit pricey but worth every penny for the (at least for me) vast increase in frequency of checking my tire pressure. When my shopping budget replenishes next paycheck I'm going to buy a set for my car as well.
Now if somebody could make a passive, real-time belt tension checker, I'd REALLY be a happy camper.