Raspberry pi as ecu

[thecoolerking]

Has anybody thought about using a raspberry pi as an engine control unit? It has a gpio ribbon connector socket & is very cheap!

[turbochris]

Interface w an arduino to get all the counters and analog inputs pwm outputs and it could be a very powerful combo. Maybe start w arduino mega just in case. It's all about the code. There should be some cheap displays available soon for the raspi's onboard display header. it would take very little power to run all this too.

[GrantB]

Im having a hard time figuring out the pro's and con's to each. The Pi seams leaps and bounds better but everyone says the arduino still has a place. I don't think a shield will help me so the Pi seems like it has the upperhand IMO. Plus i can run a nice screen in the future a little more easily.

If i just want to run a few sensors and 1-3 actuators what do you guys think i should use?

[Richard OConnell]

I think the pros to the arduino are that is has been around for a lot longer. Since everyone is using them, lots of parts and information have been made available. The Pi is newer, but i'm sure more will become available for it in the near future. If you are looking to control an engine with it, the arduino is perfect. Its extremely user friendly with lots of examples and will supply you with more power and response time than a human could ever match. The Pi is also really good and is even more powerful, but given the task at hand, its like taking out a locked door with a howitzer, effective, but overkill.

[wolfdragon]

Raspberry PI = Single board Linux computer with a small GPIO, runs decently quick for its size and is very inexpensive.

Pro: Cheap, can be programmed in multiple languages, easy to access

Con: New platform, requires Linux knowledge, requires installation of runtime environment (python, C, etc.), few drop in libraries/drivers for things such as LCDs and/or bit-banging a UART/interface, (very powerful but is not really meant for a non-programmer type)


Arduino: Atmel AVR chip running a bootloader and imported C-ish type code scripts

Pro: Long life platform, lots of dev time, many easy to use libraries/drives that you can just cut and paste, dev platform is well written and easy to use

Cons: Non-USB ones require an ISP/JTAG programmer (another piece of hardware), can be a bit expensive considering it's a board to hold a power supply and a chip, programming language has some rather unique issues if you know C or C++ already


Winner for a non Linux happy person: Arduino
If you just want something to work and not rip your hair out, it's the quickest and least painful option

If you have any electronics AND programming background, ditch the Arduino and go straight to an Atmel AVR chip or a Microchip PIC chip. By losing the arduino bootloader, the AVR will run faster and the entire memory space will be available for use. (Think of the bootloader as windows and developing software to run inside it rather than just a direct run code for your computer.) The PIC chip is just as good as it's equivalent AVR, there are feature differences etc. but PIC and AVR are both good chips. Downside: while the dev stidios are free they require you to use the datasheets to manually setup timers and ports which Arduino just handles for you. Additionally, both PIC and AVR need a programmer since there is no USB to plug in, after all it is just a bare chip...

RaspberryPI will let you do all kinds of fun things as GUI's on big monitor on touchscreens go out on the internet and pretty much anything you can do with a regular Linux box PLUS a handful of IO pins that you can make do anything you want. I have computer freak friends who are intimidated by the power a RaspberryPI has but are playing with them like crazy right now.

[GrantB]

Sounds like my Arduino will be used after all. Thanks!

[wolfdragon]

Arduino is the easy route, the others allow for doing exactly what you want, how you want.

[turbotom]

I've been through an ECU design but with the emphasis on a bullet-proof, super-reliable system as a result. You may read about the evolution of this ECU here if you like: www.technologie-entwicklung.de/Gasturbines/T-62T-32_ECU/t-62t-32_ecu.html

My recommendation would be, keep the controlling part as small and simple as possible. You won't need all that many MIPS for that job. Define a standard interface (maybe just an UART) and communicate to another system for the user interface (if you want a nice, full color display and fancy gauges, and don't forget to use photocouplers to have the circuits electrically completely independent). I wouldn't feel too comfortable with a huge operating system running in the backround, not exactly knowing what it's doing next. For the engine control job, in my opinion, the Arduino would clearly be the better choice, even better would be a plain microcontroller solution with purpose-designed circuitry to operate the engine accessories/sensors. You will be surprised how much interference a high energy ignition system may inject into the control system...

The firmware will be the tricky part and you should be pretty familiar with interrupt programming. Since I never worked on Arduinos, I'm not too sure how easily nested interrupt routines can be implemented.

Yet, the PI is a nice system and I'm considering to get one to play around a little ;-)

Cheers,
Thomas