MPGuino release one workspace

[cmags]

OK, so I got the 'guino installed, finally found my ECU, and tapped the VSS and INJ wires. Hooked it up, and would you know it, it worked right away! Immediately saw raw data flowing in. Got the VSS pulses calibrated at 8000 to match my ODO perfectly. I might calibrate to my GPS instead though since its more accurate.

One issue tho, the garbage on the LCD issue came back. Seems like it doesn't like the noise added by the VSS and INJ wires. I did notice though that it only seems to happen on the double-line screens. The big MPG screens will stay up fine. Are there any differences in the timing or anything for the displays? I'm going to have to dig in and tweak.

Aside from that, now that this prototype is working, I think its time to look into the clean install, w/ a smaller 'duino (iduino) and a backlit LCD. Has anyone come up with a green or red backlit LCD that is known to work well? I think my primary issue is a difference in tolerance between my LCD and the NKC. I just won't be able to handle the glare off a blue LCD at night (which is what I'm after since my non-backlit LCD works fine in the daytime).

[SVOboy]

I'm also looking for a new LCD in general, just because it's a tad difficult on multi-function mode in the sunlight, but now that mine is working, I have glowing reviews.

Has anyone figured out a good case to use? I have the iduino so I should be able to squeeze it into a box.

[justpassntime]

Are all Honda ecu's wired the same? Can I use the same data on my 87 Accord as those of you with 90s CRXs and Accords?

Will the 8204 number work for me too?

[wyatt]

Question:
My car is Pre-OBDII, My Wife's car is OBDII. I don't mind wiring up my car, but would rather not get into that with her car. Does anyone know if I can get a pair of OBDII connectors somewhere and wire them up for my car, and make the MPGuino swappable between vehicles? If so, how would I go about wiring up the OBDII connectors? I found a page that shows how the OBDII is supposed to be wired up, but I am not sure where to make the VSS, injector wires, etc. I was wondering if there was anyone that had tackled this one. I may be reading it wrong, but you may be able to run three of them together and into the MPGuino making it work for all vehicle types. Any thoughts?

[cmags]

^^ This project won't work via the OBD-II connector. OBD requires a communications protocol - we are pulling raw pulses from the VSS sensor and injectors for this project. You would have to tap into the appropriate lines on both vehicles and put a quick connect on the taps to switch between the two cars (don't forget power too).

There is an OBDuino in progress in another thread in this forum, but they're still in very preliminary stages and don't have the OBD communication working quite yet. This project is quite a bit further along in the process.

[cmags]

So, does anyone have a green (or red) backlit LCD working with their 'guino? Just trying to find out what works and what doesn't before I've got to become the guinea pig. It'll be my 3rd LCD (though the first two were a two-pack), but too many LCD attempts and the project starts getting expensive. Thanks!

Oh, and I found that I'm getting more accuracy using a figure of around 183M uS for the injectors. I took my calculated 365M and just divided by two and its more accurate. Once I've got my other hardware bugs worked out (LCD), I can power this thing from const. power (right now its on switched power), and will calibrate over a few tanks.

[dcb]

I've used a few green ones, They are pretty interchangeable. I have a few from mouser that I'm trying to make a PCB kit with, will release details shortly, but here it is with the veloboard:

[cmags]

Awesome. Yea, I'm not sure why I'm having such problems with my LCD, but from the thread it seems I'm the only one with the issue so I'm assuming its the LCD itself. I was planning to grab an LCD and an iduino to make a more integrated unit than my "prototype", but if there's going to be a PCB version w/ only the needed components (not the whole 'duino), that's even better. Keep us posted on the PCB, but if you have a particular LCD you're planning on using for the release hardware, let me know so I can grab that exact one and test it in my current setup. Thanks again!

[awillard69]

Yes, I've been busy. But I promised my pictures, so here they are.

Let me know if you want more or have any questions about my setup.

Basically, the LCD is mounted to some nylon stand-offs (scavenged), you can see them from the front. They are white nylon, but a Sharpie marker makes them less obvious.

The Freeduino v2.0 is mounted to the removable back using stand-offs. The guts of the interface are contained on the Protoshield. Since the shield is connected to the LCD, the shield can be disconnected and the Freeduino completely removed, or even replaced, without disrupting the device - easy service or upgrade.

The power connector was scavenged from a PC; I was able to find both the male and female ends. This one is the one with the pins, which less common in this form, normally found on the drives. The typical ones are easily cut from an existing PC power supply and will be used as ends in the vehicles. It actually came from an inline fan connector that had both ends designed to be stuck in between an existing power setup versus tapping into a motherboard connector.

The buttons are contact buttons scavenged from an old VCR (many moons ago, too cute to discard! ). I drilled two holes and hot glued them to the surface with the leads inside the case.

The case is a 2x2.5x5 from the Shack.

This is something the wife won't mind sitting in the vehicle with her!

[wyatt]

Would it be possible to use a 2n3904 transistor instead of the 2n3906? I can buy one of the 3904's, where I have to buy 15 of the 3906. Thanks.

[cmags]

I mentioned this before somewhere, but the difference between the 3904 and 3906 is NPN vs PNP transistors. They work backwards from eachother. It's definitely possible to create an equivalent circuit, but they're not drop-in replacements.

[bbjsw10]

So is the list in post #1 all I will need to build on of these, I don't wanna read all 23 pages Lazy.

Originally Posted by awillard69

The Freeduino v2.0 is mounted to the removable back using stand-offs. The guts of the interface are contained on the Protoshield. Since the shield is connected to the LCD, the shield can be disconnected and the Freeduino completely removed, or even replaced, without disrupting the device - easy service or upgrade.


The case is a 2x2.5x5 from the Shack.

Like the protosheild you have that is not in the list or did you do that on your own. I love your setup and want to copy that as closely as possible. So any help would be great. Buying this weekend I hope.

And is the script in post 1 updated with all adjustments so far.

[awillard69]

Yes, post #1 contains the shopping list and DCB keeps the code listing current. Direct any questions to him if you have a specific concern.

I went down the path of the serial Freeduino v2.0 from NKC Electronics. Since I didn't want a spaghetti mess for everything (LCD, buttons, interface components, etc.) hanging on the 'duino, I opted for the proto shield. All the connections are passed through so it was a sweet choice for a plug-n-go design.

I can pull the 'duino from the proto shield and use it in another project, if needed.

Also, there was some early concern with blowing the 'duino board, so transferring a bunch of individual connections wasn't my idea of progress. You can see my earlier attempt at the modularity somewhere in this thread's history. It turned out that I was trying to create what the proto shield already had.

The shopping list is the minimum, and yes, the proto shield does add to the cost, but it's a better choice in the long run, for my situation anyway. That is, short of a more compact all-in-one setup, like the one to put all the circuitry on a single PCB.

How much does it cost? Well, for me, here is my list, maybe others can add theirs:

Freeduino, serial v2.0: 16.99
Proto shield: 11.99
LCD 9.99
Enclosure 2.99
------------------------------
Total 41.96

This is not counting the buttons, connectors, hookup wire, heat shrink tubing, solder and any other items I had laying around or managed to scrounge/scavenge/beg/borrow/steal.

As you can see, opting out of the proto shield and enclosure can cut the cost almost in half. I like the neatness of the enclosure, myself, and the shield was a natural.

[bbjsw10]

Originally Posted by awillard69

I went down the path of the serial Freeduino v2.0 from NKC Electronics.

I like the neatness of the enclosure, myself, and the shield was a natural.

Thanks for telling me about NKC, and I love the way yours just flows and looks like an actual product. I want something nice looking and secure and yours suits that bill nicely. I am gonna order me some stuff this weekend I hope. Crossing fingers. Thanks Man.

[awillard69]

If you are going to pursue the proto shield, be warned that the version of the shield that I got had a bug in that the +5v trace was not connected across the pads. I had to solder a wire to create the connection. Only a nuisance. It's been a while since I reported it to them, so, perhaps they have revised the board and it's not an issue. Just so you know.

[drivenByNothing]

Like the enclosure awillard. I'll try and finish mine once school is out. The whole project has been on the backburner lately.

I noticed the source contains an include for eeprom.h. I missed the discussion on this, but are we saving things to the chips eeprom now? I thought about that when I first saw the project and looked into a little. I'm very interested in utilizing the eeprom.

Matt

[cmags]

^^ Yea, I think DCB is using the eeprom to store the variables for vsspulses, microsecondspergallon, etc, so that with each code update we don't need to change the #defines. Pressing all three buttons at once brings you into a setup screen where you can modify the variables.

[wagonman76]

Could someone give me a quick rundown of what the proto shield is, and why you would use it? I see it offered with the Freeduino boards but it is not required according to post 1 of this thread.

[cmags]

It's basically a piece of prototyping board with headers that will connect directly into the freeduino's headers, so that you can build your auxiliary circuit and snap it together with your 'duino. Just a simple modularity thing - not required, but keeps your board clean. Check out the difference between awillard's 'guino and dcb's original. You'll understand.

[wagonman76]

Oh thats cool. Ive already got my stuff on order but I might just try one of those too. Of course I could just take a pc board and solder some pins in the right places to make something similar.

I was thinking of doing something similar, using a piece of hard drive cable to connect parts. Ive been thinking about making a 2 piece setup for cleaner installation in my dashes which have limited real estate. One half would have the display and switches in a small clean enclosure, with a hard drive connector. That would mount on the dash, one custom matched to each car. The other half would have the Freeduino and all the rest of the parts on a PC board in just whatever type of enclosure, with a hard drive connector, and it could be tucked in behind the dash. And of course the two would be connected with a neat looking hard drive cable. Or something different if I have interference problems or anything.

Then I can take the mpguino out, either to reprogram it, or to swap between vehicles. And keep the display unit in place already made for each dash.