Wireless Sensor for detecting light

[chroot]

Something like that might work. Honestly I still think it'd be easier (and even more intuitive) for the user to have a small box housing the transmitter, and a set of wires with plugs that he/she can plug into the various sockets on the truck's trailer wiring harness. Nothing sticky, nothing necessarily outside the vehicle. It'd be cheaper and more reliable.

- Warren

 

[Danger]

Actually L&R might be better "D" for drivers side and "P" for passenger.

That would totally screw up your British market.

I just thought of something here. You wouldn't even need a trailer wiring harness (same as with your original idea). How about just clamping inductive pickups around the wires leading into the taillights? It would be a very weak signal, but so would one from a phototransistor. The amplification stage should be similar.
If you're looking to pulse the LED's for power conservation, be very careful. Your pulse rate will have to be at least 25 Hz. As I pointed out in an unrelated thread, a flash rate of 16-22 Hz (particularly with a red light) can stimulate an artificial alpha rhythm in the brain, which results in a seizure very similar to an epileptic episode. The technical term is 'photic stimulation', but it's usually called 'flicker vertigo'. And if the observer is already epileptic, it's far worse. You could have one hell of a liability suit on your hands if that happens because of your product.
As for the 'remote control of everything from the car' concept, a lot of new vehicles are bluetooth equipped, which pretty much covers that.

 

[chroot]

Bluetooth is only good for six to ten feet; it's meant only for use within the cabin.

- Warren

 

[Danger]

True, but it integrates the driver's laptop, cell phone, iPod, Blackberry, etc., some of which can access the required functions through WiFi or cellular internet.

 

[robhoski]

The problem with hard wiring into harnesses or directly into the taillight wires is that the "convenience" factor goes away. Picture a woman driver (no offense ladies) who has no knowledge of such systems trying to figure out how to fix her non-working taillights on the road. If you told her to take out the emergency kit and put the sensors on her taillights and the remote units on the rear of the towed vehicle she might be able to do it. Ask her to locate wires and I think we all know what would happen. :) Also, they have systems that are wireless which hook up to existing wires and are used mostly for large farm equipment as a temp light source for driving the machinery down the roads. Additionally, plugging in a clip into the existing wire harness on the back of a truck would work but only if your truck harness is working. Sometimes that is where the problem is. I've had some lights work and some not due to my harness and not the trailers. Bad grounds are common too.

 

[NoTime]

Not to mention that getting to the wires often requires some disassembly on newer vehicles.
On my vehicle I have to remove 2 bolts and some screws to connect a harness or change a light bulb for that matter.
I did get a factory harness with the towing package and installing that was a at home with all my tools.

I suppose I should be happy it only took a half an hour. Changing the sparkplugs is a 6 hour job requiring the windshield wiper cowl and intake manifold be removed to do it.