Volif_
Probationary Member
- 22
- 11
- Nov 20, 2022
-
Ljubljana,
Europe
Hey everyone,
I've been working on something for my car for a while now and wanted to see if anyone here would be interested in following along.
How it started
About three years ago this began as a standalone Arduino project for a course in my undergrad physics program. The inspiration was my 1990 Eclipse 1.8, which liked to misbehave now and then, and I got tired of having a laptop plugged in every time I drove just to see what the ECU was doing. I wanted something that lived in the car.
It was my first ever Arduino project, and my professor helped me a ton along the way. I learned way more than I expected, both about how the car talks and about electronics in general. What started as a class project slowly spiraled into what it is now.
Credit where it's due
A big part of getting started was rizal's Mitsuduino work: his blog (https://mitsuduino.blogspot.com/) and his thread here (https://www.dsmtuners.com/threads/on-board-diagnostic-between-mitsubishi-ecu-using-arduino.464711/). He got an Arduino talking to a 1G ECU, but the project was never finished or fully documented, so there were gaps to fill. Still, it pointed me in the right direction and saved me a lot of time. Thanks also to Steve for explaining the echo and the command list in that thread, and to Christian who put together the commented E931/E932 disassembly, which became my main reference.
Talking to the ECU
Getting reliable communication with the ECU was the hardest part of the whole project. A few things that tripped me up:
From Arduino to Argus
The Arduino proved the concept, but I wanted a real screen, proper logging and room to grow, so I rebuilt it as Argus, a touchscreen dash that runs on a Raspberry Pi.
What I used (broadly)
What Argus does so far
Where it's at
Still very much a work in progress. The Arduino version works, but I'm waiting on my Raspberry Pi 4 before Argus goes in the car. So far Argus has only run against the simulator, so real in-car testing is next.
Ideas for later: add-on sensors (the stock 1G ECU has no MAP sensor, so boost, wideband AFR, EGT and oil pressure/temp would come from extra sensors), GPS, and one-tap log export to a USB stick.
Would you want me to keep posting updates here?
What would you want to see on a screen like this?
Thanks for reading, and thanks again to everyone whose old posts made this possible.
I've been working on something for my car for a while now and wanted to see if anyone here would be interested in following along.
How it started
About three years ago this began as a standalone Arduino project for a course in my undergrad physics program. The inspiration was my 1990 Eclipse 1.8, which liked to misbehave now and then, and I got tired of having a laptop plugged in every time I drove just to see what the ECU was doing. I wanted something that lived in the car.
It was my first ever Arduino project, and my professor helped me a ton along the way. I learned way more than I expected, both about how the car talks and about electronics in general. What started as a class project slowly spiraled into what it is now.
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Credit where it's due
A big part of getting started was rizal's Mitsuduino work: his blog (https://mitsuduino.blogspot.com/) and his thread here (https://www.dsmtuners.com/threads/on-board-diagnostic-between-mitsubishi-ecu-using-arduino.464711/). He got an Arduino talking to a 1G ECU, but the project was never finished or fully documented, so there were gaps to fill. Still, it pointed me in the right direction and saved me a lot of time. Thanks also to Steve for explaining the echo and the command list in that thread, and to Christian who put together the commented E931/E932 disassembly, which became my main reference.
Talking to the ECU
Getting reliable communication with the ECU was the hardest part of the whole project. A few things that tripped me up:
- The ECU talks at an odd 1953 baud, one byte in and one byte out
- Everything runs on a single wire, so every request you send echoes back before the real answer
- Diag pin 10 has to be grounded, otherwise the ECU just flashes codes on pin 1 instead of talking serial
- Working out which request code is which sensor, and how to turn the raw numbers into real units
From Arduino to Argus
The Arduino proved the concept, but I wanted a real screen, proper logging and room to grow, so I rebuilt it as Argus, a touchscreen dash that runs on a Raspberry Pi.
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What I used (broadly)
- Arduino (C++) for the original version
- C++ for the ECU communication in Argus
- Qt with QML for the touchscreen interface
- Linux / Raspberry Pi OS on the Pi, and WSL to preview the dash on my Windows laptop
- A small Windows tool for testing the cable, and a web page for viewing logs in any browser
What Argus does so far
- Live data: 20 parameters from the stock ECU (RPM, coolant and intake temps, O2, fuel trims, injector pulse width and more), plus calculated injector duty
- Build-your-own dash: up to 5 swipeable screens. Long-press to edit, drag gauges around, and pick the value, style, size, colour and shift lights for each one. Street, Classic, Track and Tuning layouts to start from
- Gauge styles: big numbers, arcs, needle tach, bar and LED-bar tach, trend lines, centre bars for O2/trims, sweep tach
- Live graphs you can pause, scroll back through and read with a cursor
- Data logging to CSV that saves every few seconds, so pulling the key doesn't lose the log. Review logs on the screen or in a browser on any PC
- Diagnostics: read and clear fault codes, plus a raw console for the curious (actuator tests are blocked on purpose)
- Looks: 7 colour themes, a custom accent colour, and your own logo if you want one
- A start-up intro that also shows the ECU link status while it connects
- Scales to different screens (including 7" displays) and boots straight into the dash on the Pi
- A built-in ECU simulator so I can develop and demo without the car
- A cable test tool that tells you whether a problem is the cable, pin 10 or the port
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Where it's at
Still very much a work in progress. The Arduino version works, but I'm waiting on my Raspberry Pi 4 before Argus goes in the car. So far Argus has only run against the simulator, so real in-car testing is next.
Ideas for later: add-on sensors (the stock 1G ECU has no MAP sensor, so boost, wideband AFR, EGT and oil pressure/temp would come from extra sensors), GPS, and one-tap log export to a USB stick.
Would you want me to keep posting updates here?
What would you want to see on a screen like this?
Thanks for reading, and thanks again to everyone whose old posts made this possible.
