4T65E Shift controller with Microcontroller - Videos inside

[Imp558]

Baby steps, but I have a microcontroller running the program now. This project is still a ways from a working model but I thought it was interesting enough to warrant a thread.

 

I have a lot going on but hopefully there will be some version of this in the GS late summer.

 

Shown here is a demonstration of the PIC selecting the proper parity for each shift solenoid as I cycle through both the paddle inputs and the push button select inputs.

 

Forgive my cracking puberty sounding voice, my seasonal allergies started today.

 

Edited April 1, 2018 by Imp558

[Imp558]

Working on getting it to work on ATMEGA16, that device is much too big but I'd like to get some experience with it. The output ports are doing something strange so I need to learn how to use it properly.

 

For this project the PIC16F628A that I have in the video i should be perfect, it even has a PWM output so if I decide to do a TCC later it's just a flash away.

[vipmiller803]

Were you thinking a ratcheting shifter for the direct select? Paddle shifters alone are going to be an interesting install. I always imagined having one of those with a switch to make it live and a thumb button for the tcc

 

 

[Imp558]

I am thinking ratchet shifter, like a B&M mega or so. For the direct select I initially pictured 4 switches but your solution is more interesting.

There's a bunch of paddle shifter add ons out there too, also there's the option of mounting a switch right on the wheel and using the old airbag wires to get up there.

[Imp558]

I was just playing with the code. I can use the existing P/N switch to tell the microcontroller what gear is being commanded by the shifter. Looking through the schematics I can see the parity of each input from the switch in each gear.

 

I'm thinking: everything's normal until the gear selector goes to first gear, so long as the driver never manually shifts below second it's just like factory.

 

When first gear is commanded it enables the controller, the controller enables an output to switch a pair of small relays, opening the circuits between the shift solenoids and the PCM and closing the circuits between the shift solenoids and the controller's output transistors.

Also turns on an indicator so the operator can see - maybe something like "Manual Mode".

 

Now the controller is controlling the shift solenoids and it's in first gear.

 

When it sees the other gears get commanded on the P/N switch it shifts to that commanded gear, up or down.

 

Once the controller sees a neutral signal it disengages, allows the relays to close back to PCM control, and turns off the indicator.

The process waits to repeat, no manual mode, just a normal 4T65E until somebody shifts it into first again.

 

I'd like to bring paddles in too but the shifter would have to manually be put up into fourth and the paddles would have to nullify the fourth gear P/N input until the controller saw 3rd or neutral. That's do-able so I may tinker with it. I'm going to borrow a P/N switch off one of the cars and play with it.

[vipmiller803]

That sounds neat.

 

A few things to keep in mind:

 

You're going to have one angry pcm at the end of all this. All sorts of solenoid codes.

 

I see no pwm incorporation so shifts will be quite hoppy. Also, you might have line pressure problems mid gear if the pcm tries to shift halfway through your pull in one of your gears. Perhaps you can tell the pcm you're in neutral via P/N switch inputs while you're in manual mode? It's only one extra relay and should free up a lot of headache.

 

You're also going to lose all the safety the pcm gives to the engine doing the relays like that, like shifting down accidentally to first when going 80 will not slam you in first and overrev your engine/barbecue your trans clutches. The more solidified shifts with the ratcheting shifter will give you back some of this confidence, but it's still a concern for someone not used to the car.

 

You'll need a tcc lockout for manual mode. If you're revving high in first or second and the pcm thinks it's in third, it can easily turn on tcc erratically. This might get solved by what I mentioned above. Another solution is to tap into the brake switch. The pcm will not lock tcc while the brake is on.

 

I am sure you know this but I'll throw it out. Be sure to put dumping diodes to any mechanical relays you use (or test with) for back current. Transistors tend to not like mechanical relay back spikes.

[Imp558]

I'm a little concerned with the PC solenoid. The TCC should still be looking at the internal switches and only engage appropriately. The guys who are running without a PCM don't appear to be controlling the PC solenoid so I think the rest of that part of the story will have to wait for the GS this summer. This could be really interesting, I'm hoping to have manual mode for our june meet- if we have one.

Edited April 3, 2018 by Imp558

[Imp558]

Oh, I'll just turn off the error reporting in the PCM for solenoids and incorrect gears

[Imp558]

I ordered 3 new Microcontrollers. Before long I'll have some favorites. Still have to pull the P/N switch off the Regal too so I can try this with parity.

[Imp558]

Pulled the P/N switch and found some loose plugs for it. Also wrote a version of the program that's pretty cool. I wrote some really neat denouncing on the inputs. It was challenging using the parity bits from the P/N switch because they don't chage state at once. Also found some DPDT 5V coil relays with 8A contacts for the PIC to use to take the solenoids from the PCM but they missed the last Mouser order. A friend of mine ended up with a bag of pretty wicked automotive grade drivers with a bunch of little built in features so those may be the solenoid drivers. I should be able to switch the relay with a simple 3904 but there's MOSFETs in a drawer and some 3055 transistors and stuff so it's covered on that front. Now if only I had a car together for when this prototype is done.

[Imp558]

Naturally I'm not in a position to test this since I've fallen behind putting said transmission into the car...

 

I still wanted to keep learning so in the mean time I've written a couple of other programs for fun.

 

I have a very tiny PIC10 switch that has two input channels and two output channels and uses momentary inputs to toggle their respective output on or off.

If you're into electronics you know what a bitch that is to do reliably with simple electronics but thanks to simple one-shot commands there's no need for much of anything. No de-bouncing even.

 

The other day I wrote a car alarm that essentially behaves much like a factory one but with intrusion detection.

Currently I can have it work like any other car honking alarm but it does a unique pattern of honks and light flashes  to take the mystery out of whose car alarm is sounding and remembers which input was triggered after the auto reset.

I can make it flash a number of blinks on the LED to indicate where the intrusion was or run a dedicated LED for each input to indicate which input was triggered.

I've been reading up on serial data communication and will eventually be able to have a small dot matrix display just say in plain english that the trunk was opened or a shock sensor was disturbed but I'm not at that skill level yet.

 

Tonight I wrote a neat one, kicking around the idea of using a much newer steering wheel with cruise control buttons so I wrote a program to read resistance to 20% accuracy (could be 1% for that matter but 20% seemed more realistic) and enable outputs.

Of course this could also be used to recycle steering wheel switches for paddle shifting too.

 

I have a hush-hush project to test yet too - more on that later.

 

While this is all interesting and a great learning experience I'm not sure what projects may or may not get implemented in the end but I'm writing PIC programs in simple Ladder and bringing them to life IRL so it's crazy fun.

[jimmyfloyd]

sounds like fun. If you could write a program that mimiced the mute button on the SWRC being pressed that I could hook into the Radio to clear it, that would be very helpful. 

 

Also, if you want a Saturn Aura/G6 leather wheel with paddle shift and SWRC with Cruise and Radio, I'll sell you the one I have cheap. Just taking up space. 

[Imp558]

That shouldn't need a microcontroller, if it's just that then a switch with the right resistor would make it mute.

[Imp558]

Also, if you want a Saturn Aura/G6 leather wheel with paddle shift and SWRC with Cruise and Radio, I'll sell you the one I have cheap. Just taking up space.

Do you have a picture of that wheel? What year?

[jimmyfloyd]

Yeah, unfortunately, I don't know what the resistance would be, and they crushed the 94 vert last week some time, so I couldn't get the SWRC out of it. 

 

And this is the style wheel (don't have an actual picture at the moment, but looks just like this.) uses the same airbag as the G6 so you could get a pontiac logo

 

[Imp558]

So now I'm to the point that I can use serial data communications, if I build the car alarm it should be able to display on a dot matrix display. 

For that matter the display would be easy enough to use as a sort of DIC to do other things.

Tonight I started on a keypad keyless entry system, totally easy. But to make the code programmable and make it so the user can use the same number for more than one digit in the code is really tricky, this one will take a while but it's good practice for learning how to manipulate variables. 

And most importantly I'm still having fun.