Saw one this morning on Facebook where a teenaged girl has invented an alarm of some sort (couldn't link to the report because my work program wouldn't let me) to alert parents that there's a child in the child seat. Don't know exactly what it's about, but if it does a good job it would take off like wildfire. I don't have a need for this, being childfree, but there are millions of parents out there who would buy it.
It's a mat for the car seat the sets off an alarm on the parents key fob, the car and...something else. the parent's phone? If the key fob gets further than a certain distance from the car and the mat detects a child still in the seat. Great idea, hopefully it can get past fabrication.
See, the reason I like the idea of something like that is that (I assume) it sets itself up. i.e. if it detects a child's weight on the mat (I assume it tares out the weight of the carseat itself or that it goes *on* the carseat), it sets off the alarm. So the parent doesn't have to do anything each trip, just set it up the very first time. I like that.
If it goes on the market, I would *especially* recommend it for parents with only babies/toddlers or who drive around only with those babies/toddlers, and parents who alternate who drops off a child or otherwise don't have a routine that *always* involves the same thing.
It seems like in most cases, there's no older child in the car (who would also be in the back and who would easily see that the baby was being left in), and it's a change in routine (mom sometimes takes baby to daycare, other times dad takes her, dad forgot that it was his day). I worry less about it now because a) I always have the kids with me, so it's habit to open the back every time, and b) I have older kids, too, and they have to come out the back and they would certainly get my attention/open the car if I somehow left them all or a baby in there.