great bump. i've been mulling this over for a little now, wanted to start looking into it, and as always, someone here already has.
looks like some very good research has been done. i saw a post (too lazy to find it) mentioning that the ECU sends 12v to the motors for a time interval based on seat location. i'm curious if that means the motors are timed to place them into position, or if there are actual position indicators back to the ECU.
engineer by trade, i could throw some time to this to see what we can get working. i have an 05 v8 and would love this. there are always other options than stock ECU. i would bet we could create a controller to handle this. it would be great if there are position indicators already wired up.
Would it make sense for Toyota to have used stepper motors for the seat motors? If that's the case (and I'm only guessing), then they wouldn't need sensors. The ECU would only have to remember the two "saved" locations, and the "current" location. Then, when asked to return, it would know how many pulses to apply to each motor, and in which direction in order to get
back to the stored state.
If I were designing this, that's how I would do it... but then again, I'm not sure of the cost of stepper motors, to know if this is feasible.
(BTW, I have an engineering background too... in case you can't tell !)
If you have the time and the interest in checking out the motors on the seat, maybe you can tell if they are stepper motors. If they are, then I think we've solved the design issue. All we would need is a controller that keeps track of the pulses sent
to the motors.
Also, this would be consistent with the idea that the adjustment switches for the seat go to the controller unit first, and not directly to the seat motors.
If there were sensors on the seat so that the controller could read the seat's position, then you wouldn't NEED to have the switches go through the ECU (although you still COULD have them run that way), but the switches could simply control the motor, and the ECU could read the position location of each adjustment axis on the seat to determine where it the seat currently is and where it needs to be.
BUT... if you used stepper motors to control each motor, then all input would have to go through the ECU, so that the ECU could send pulses to the step motors,
and keep track of exactly e the seat is based on the number of pulses sent and the direction of those pulses. So this design would at least be consistent with what we know so far about the memory seats... namely the the memory seats use a different switch where the seat switch inputs go directly into an ECU.
I could envision a nice prototype built out of an Arduino board to prove that the concept works, and to easily check out and calibrate a solution.
Anyone who has an oscilloscope, might be able to tap into one of the motor wires of a seat with memory to see if motors are receiving pulses when the seat
motors are running. (I only had access to those tools more than 20 years ago in school... for all I know, maybe there are USB-based oscilloscope like readers that are cheap and use a PC to handle all of the plotting and displays).
If it worked, I have no current idea how a Arduino prototype would move from prototype stage to a true production run of product.
Maybe it would be based off some commercially available programable stepper motor ASIC.
I have good training, but I was always a software guy, so I've never had any professional experience producing hardware production, and the few circuits that I've tried to design for my hobbies have always frustrated me (not to say that I didn't get at least *some* of them to work eventually!).
College was a long time ago, and since I don't design circuits for a living the few times that I've decided to give it a try on a hobby, I've always been frustrated by issues, because I'm rusty and don't have recent hands-on experience so it takes me too long... not that I won't try. For example, I recently built a prototype pulse-width-modulator in order to provide digital speed control to my boat's electric trolling motor. That was a fun project!
-Phil
-Phil
