I know I'm probably bringing back a completely dead thread however I personnally have been working on my own arduino mega transmission control module that I plan on having in car and functional this coming spring/summer.
Youtube video for proof of concept can be found here: https://www.youtube.com/watch?v=PA3p1UhnNxE
Pretty much at its core explanation:
Its a 4L80e transmission controller with 4 current operating modes. Those modes are Full Automatic control (put shifter into OD and drive), Full Manual Valve Body (makes the transmission act just like its a full manual valve body equipped transmission), Paddle Shift using switch inputs, and Drag Race Mode (makes the transmission act like its equipped with a air shifter using a RPM trigger).
Currently using a 16X2 LCD display which may change to a OLED display, havent decided on that one yet.
On the car I'm currently putting it on which is a 1982 Pontiac Firebird that I LS V-8 swapped, sporting twin turbo's and nitrous, the engine is currently controlled by a MegaSquirt 2 ECU. It has CANBUS dash broadcasting which is turned on, and I'm receiving data like engine RPM, TPS, IAT, CHT, etc into the arduino trans controller module using a CANBUS module, which is working flawlessly in my "bench testing".
I also have the "sloppy trans brake" setup on this module too, which actuates 3rd gear instead of first while pressing a button, so the engine has less mechanical advantage over the brakes and allows the engine to come up on the torque converter easier. Once the button is released, the module re-activates 1st gear which does a power down shift and then the vehicle takes off. Sounds odd but the sloppy mechanic guys have tested the setup out with great success, so I'm giving it a whirl on my setup.
As you can tell in the video its still in R&D phase. I'm currently buttoning up my VR sensor input into the module to provide a MPH input, so I can switch the fully automatic mode's upshift and downshift shift tables from RPM to MPH based like the OEM's did it, and then its getting the project into a enclosure and doing on vehicle testing.
So if any of you want to check out my work or have any advice, help, whatever you would like to provide please let me know. I'm probably a novice coder compared to ya'll who coded the speedunio, well I'm sure I am but it is a bench working prototype to say the least and wasnt sure if anyone here would still be interested in it or not.