Looking for a solution for detecting if someone is in the passenger seat of a vehicle

[ts1234]

I'm trying to work out a solution for detecting if I'm leaving home by myself in one of the cars, or with someone. I'd like this to happen with no intervention from the passenger(s) at all. The best thing I can think of right now is some sort of motion detector under the seat that powers up a USB BT that can be detected by Geofencey/PHLocation apps. I can't depend on those apps for triggering arrival and departure, as my cell service outside my house is far from stable, but if they could detect a BT device at any point as I drive out of my neighborhood and relay that back to HS, I could then adjust events that need to run differently for no one being home vs. someone is still at home. Obviously, it couldn't really tell if the passenger was someone living at the house or a friend, but I can work around that.

The ideal solution would be able to have a relay that powered up the BT device by the circuits that detected if either the seatbelt was buckled or the system that detects weight of a passenger in the seat for triggering the airbag functionality. The latter certainly seems like something I don't want to mess with unless it was obvious it the integrity of that circuit would not be impacted.

If any knows anything about the feasibility of using those circuits, or has other/better solutions to try...please let me know. Anything "inside or outside the box" would be appreciated. Thanks!

[TC1]

Most modern cars have a passenger indicator on the dashboard somewhere, it's function is to disable the passenger airbag if no one or a small human is sitting in the seat. You could put a light sensor over the indicator or tap into the circuit going to the bulb.

Here's an explanation of how the Honda system works, but it's pretty much the same for every vehicle.
http://techinfo.honda.com/rjanisis/p...3B5167B78.html

[jon00]

If you are into Arduino stuff, you could mount a AK9753 Human Presence detector on the front dash/mirror/sun visor (on the passenger side) combined with an ESP32 to provide a switched voltage output.

https://www.sparkfun.com/products/14349

Have you considered BT detection with your home directly?

[ts1234]

TC1 Thanks! - It's how to access that not being an electrical genius. I can get by with connecting things, but things like judging impact to an IC are above my pay grade . I'm assuming it's a 12v circuit and that it would likely be able to support a usb power source w/out blowing a fuse hopefully. My older car has a light on the dash that comes on as an indicator I might be able to get to without too much worry. My newer jeep doesn't seem to have an indicator...or at least I can't find it. It may be on the "computer" screen and only comes on when in child seat mode. While I really doubt anything would ever happen since I'd probably never put a child in a front seat anyway, messing incorrectly with that circuit might keep the airbag from firing when there was an adult there, so I need to be 110% certain using it has no impact. I'm hoping maybe somebody out there has that answer.

jon00 Thanks as well ...I'm always trying to solve for needs that seem to be outside the realm of "normal/common" and clearly are going to need to learn the ESP stuff sooner...just to name a couple...indoor retractable surveillance cameras and devices to open/close my plantation shutters without butchering them are just a couple that have been on my list for years.

[TC1]

I share your concern regarding safety, I'm 99.9% sure detecting the bulb being on or off won't effect the air bag systems. Think about it, they have to assume the bulb will eventually burnout or go bad, so the circuit going to the bulb is designed *only* to be a visual indicator for the human. The air bag systems are designed to operate independent of all other systems and need to be foolproof, hence why they are so expensive to replace (you can not repair an airbag once they deploy in an accident, they literally replace *everything new* including the wiring harness).

Someone makes a an indicator lamp detector remote... it's simply a photodetector you tape over an indicator lamp on like an HVAC system and then it sends a signal (maybe wifi) when it goes on or off. It's a product to make an appliance/system remote status capable. I tried googling for it but can't find it right now.

[Michael McSharry]

The seats normally have a sensor in the seat so that when activated it knows the seat belt should be connected. For those more mechanically inclined a microswitch or a reed relay could be similarly mounted. There are also pressure sensors such as used in mats. Strain gauges also perform this function.

[jon00]

The seats normally have a sensor in the seat so that when activated it knows the seat belt should be connected.

Most car's these days have their sensors connected to the ECU which is much more difficult to monitor. I know you can buy suspect emulators to pretend a sensor is operating when missing!

Personally a separate sensor (whatever the form) would be my way to go.

[jmaddox]

Rather than sensors inside the care, what about sensors outside the vehicle? A motion sensor aimed at the passenger door, or a pressure sensitive mat on the passenger side. Then you just have to tie their trigger to departure of the vehicle. Of course this assumes you have as relatively stable environment like a garage and you're normal path to enter the vehicle is from the drivers side.

[ts1234]

jmaddox...sadly the Jeep is out on the street. My Solstice coupe is in the garage and something like that might be doable. BTW On a side note. I lived in Dallas for 20 yrs b4 Denver. Not really an enjoyable year for football in either city.

jon00/Michael...I am leaning toward adding a sensor whether reed type or inferred motion under the seat in the Jeep. The reed would be simpler to work if seat based but likely harder to install. Motion would probably be harder to build but maybe easier to install. A floor mat approach with a pressure switch also sounds fairly easy to install but may be harder to keep it triggered long enough for for everything to get back to my HS. I do only need it to trigger "on" long enough once per trip since I can turn it off in an arrival event. I might be able to use a really thin fairly large metal plate to improve switch activation since feet are probably close to but not always in the same place.

TC1...HS makes a LED light sensor and it should with a little modification work for this directly through z-wave at the start of a trip since the Solstice is parked in the garage all the time and surrounded by several devices that can help it route back to my server. I happen to have one laying on my desk I'd just bought when they were on sale for another project. I may just have to buy another. The jeep has no light for this...seems like it would have too...but it's likely built into the touch screen controls somewhere.

Everybody...GREAT suggestions THANKS!

[HSAccord]

Not trying to redirect your focus, as the seat detector stuff has been interesting to read. But, have you considered using something like Ultramon to monitor your network for the presence of the MAC addresses of your phone(s)?

[TheGerman]

How about a simple wireless motion sensor under the seat monitoring the foot area? You should be in wifi range when in the garage or close to the house and it could be a cheap solution worth a try...

[ts1234]

HSAccord --- Great idea! maybe as primary but certainly as a double-check since she could just be gone when I left. Building real life activities into events is always my biggest challenge as people do unexpected stuff

TheGerman --- I opened with that and I am think that may be the best answer now...but silly me I was trying to overthink this and tie it into BT...zwave ones will likely work. I know it will in the garage and I can probably get it to the one parked on the street with a little effort. Though I may need to tweak it's viewable area a little since light can trigger them.

[HSAccord]

HSAccord --- Building real life activities into events is always my biggest challenge as people do unexpected stuff

I keep telling my wife everything would work perfectly if she'd only just listen to me and follow my instructions. 😁

[ts1234]

HSAccord - I seem to have the same issue and it's my guess there will won't be an upgrade to fix that plugin anytime soon

[ts1234]

HSAccord - Ultramon - For some reason I thought iPhones basically went to sleep sometimes and were tough to monitor that way. If that is not true and it's stable, I used it for other things a while back and that might be really handy.