Building an MPGuino, need affirmation

[Ecky]

Below are the parts I've picked out, going off what's available on the wiki. I'm not necessarily going to order everything on amazon, just confirming that I've got it all right.



Arduino board:
Arduino UNO


Box:
Amazon.com: Box for Arduino: Electronics
(or I might cut into my cluster instead)


LCD:
Amazon.com: microtivity LCD Module 1602, White on Blue with Backlight: Camera & Photo


2N3906 Transistor:
Amazon.com: 2N3906: Industrial & Scientific


220 Ohm resistor:
Amazon.com: 220 Ohm 1W Flameproof Resistor 10 Pcs.: Electronics


Am I reading right, 50k resistor? Maybe 2x 100 in parallel, is 51/47k close enough? Would this 49.9k resistor work?
MF1/4DCT52R4992F KOA Speer Metal Film Resistors


5.1V-1W Zener Diode:
Amazon.com: 5.1V-1W Zener Diode: Electronics


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I assume if I do further reading on the wiki I'll figure out how to program it. I've never used an arduino before...

Is it safe to hook it straight up to the car battery, or should I put some kind of transformer between it? How big should my fuse be?

I'm sure I can find some suitable buttons at radioshack.

What am I missing? What do I need to know?



_________________________________

EDIT: MPGuino complete!

[Ecky]

Does it matter what the watt rating is on the resistors? Will the arduino uno be fine or should I get another model?

[Ecky]

I ended up buying most of the major parts here:
Adafruit Industries, Unique & fun DIY electronics and kits

I got the latest revision of the Uno, a new soldering iron and 60/40 tin lead solder, some 22 gauge wire and 4 buttons. I also purchased their multicolor LCD.

I'm going to find the resistors locally and buy the transistor and diodes from another location, will update as I go and probably turn this into a build log.

[meelis11]

Originally Posted by Ecky

Does it matter what the watt rating is on the resistors? Will the arduino uno be fine or should I get another model?

Watt rating does not mattr much because we do not handle big currents here. 1/8 or 1/4 watt should be ok. Use what you get.
Same with resistance - in place of 50ohm resistor, you can put 51 or 47 ohms. Cheap resistor tolerance is few % anyway (+-3% maybe)

[Ecky]

Originally Posted by Ecky

Is it safe to hook it straight up to the car battery, or should I put some kind of transformer between it?

^

[Daox]

The power regulator on the uno will take care of converting the 12V power from the car down to 5V for the chip.

[Ecky]

So far I have the screen, buttons, and arduino uno r3. I'm waiting on resistors and the transistor before I stick it in an enclosure - which I haven't decided on yet.

Setup was a bit tricky. The wiki states that you need to use the arduino 0011 environment, but the uno r3 isn't support. After some reading, I figured out that this is because the original arduino's storage is very limited, and for whatever reason, later revisions of the environment compile the same code, larger. However my Uno has more storage than the original arduino, so 1.0 worked fine once I figured out I had to manually select my board and change the output to com3.

I was rather impressed by all of the calibration options, but I have absolutely no idea how to figure most of them out. VSS/mile I can guess - it's probably the same as the Acura Integra LS, which shares both the drivetrain and wheel size with my Del Sol. However, injector delay? What does that even do? There were several settings I just left stock.

Will update when I get it fully assembled, with more pics.

[Speeed3]

You can check vss/mile with known distance. If the known distance is 10 miles just set vss to 100 and the distance mpguino shows is vss. Discard the decimal marker.

Injector delay is time injectors take to open it is subtracted from each injection pulse.

You can ad injection_pulses/tank display keep track of what mpguino displays your tank gallons and injection_pulses were and what gas pump gallons were. It will take 2-10 tanks to get the delay.

Or you could just leave delay as is.

[Ecky]

I'm having another issue - I can't get the to the MPGuino setup again!

I woke up this morning to find my contrast was back at the default value of 95, so I hit the reset button, but it booted back up and skipped setup. I reuploaded the code, but it still didn't go to setup, it simply booted up. I changed the stock parm 95 contrast to 0 (the value that works with my screen) and reuploaded, no dice, display contrast is still wrong and it's not going into setup.

Any ideas?

[Daox]

Are you sure all your connections are solid?