iDuino MPGuino

[cmags]

Originally Posted by Axaday

I intended to do it the other way around, but I like your idea too. Do they sell phone cords with a female end?

Edit - Could anyone, without seeing my car, estimate how long a phone cord I would need to do like he said?

According to: American Wire Gauge table and AWG Electrical Current Load Limits, 26 AWG wire is good up to 2A... We're using about .5A so you should be good there.

They do sell phone line extension cords, but they're not that inexpensive... probably around $8-10 at RatShack. What were you planning on if you weren't going to add a jack? Or were you just going to use phone wire because that's what you had handy, and just wire directly from the board to your car? That would work OK, but would require cutting/splicing if you ever needed to pull it out for updates or repair.

If you have one of those computer hard drive splitter cables, that has a male and female molex connector that you can cut off, and 4 pins each. A nice quick disconnect. Those are only like $3-4 at radio shack and you could splice whatever wire you want to hook everything up.

Lengthwise on the cable really depends on your car, where you're going to tap everything, and where you're going to mount the 'guino. Unless everything is near to eachother, I would recommend using separate cables at least for power/gnd and injector/VSS. This is what I did - power/gnd is a twisted pair of 18AWG to the battery, and injector/VSS is another length to the ECU. They're both in different directions from my 'guino so a 4-conductor cable wouldn't have worked out.

[Axaday]

I found a short phone splitter and have cut off the outer plastic so that I have two female phone jacks (jills?) at one end and 4 colored wires about 3 or 4 inches long on the other end. I'll put that in the unit and use a long phone cord (hopefully) for everything permanent in the car. Once you take off the outer wrap, it is 4 wires that can go in different directions if they need to. I don't know what all sizes phone cords come in, but it seems to me that a 15 foot cord should reach anywhere I need it to, right?

I'm looking over the wiring diagram now and looking up what all the symbols mean and thinking out what I'm going to do. I have a breadboard with copper contacts on one side of it. I'm following the speedometer sensor wire as it comes in and it first comes to a resister and then a zener. Am I going to solder the resister and the zener onto the breadboard with the correct ends next to each other and then smudge the contacts on the breadboard together between them with some solder? And then solder the wires onto the leads? (My former soldering experience consists solely of taking out and replacing pieces in my old DVD player to extend its life, so a lot of this is very new)

Everywhere that I see a T in a wire, do I just remove some insulation and solder the tip of a wire on the side of another?

My Voltage regulator's package shows ground in the middle and out and in on the outsides, but I don't see any sure sign of which way is up when I'm holding the thing in my hand. It has a metal area with a hole punched in it that isn't as thick as the rest of the block. Do I lay that "tab" face down to make it like the diagram?

I see one wire coming to each end of the buttons, but my buttons have 4 legs. What do I solder the legs to?

I see one places where two adjacents contacts (D2 and D3) on the iDuino are both getting fed by the same green wire. Is it fine to solder the wire to one of them and then smudge them together with solder? Is that just being sloppy?

[cmags]

The biggest issue with running the 26AWG wire outside the jacket, separated is that the wires are really small, and the insulation really thin. This makes them very prone to getting nicked and shorting out, or breaking. That's why I typically use at least 22 or 20AWG in the car. If I do use smaller, I leave it in its outer jacket. You might want to look into picking up some heavier wire for the bulk of the run, and hook it up to an inch or so of the 26awg with the phone connector attached. This hookup wire would be fine: RadioShack.com - Cables, Parts & Connectors: Wire: Hookup wire: 75-Ft. UL-Recognized Hookup Wire (22AWG)

If you have just a perf board w/ holes individually clad in copper, then yes, you put two pins through adjacent to eachother, then "bridge" the two with solder. If you don't have a lot of experience, it may be easiest to bend the legs of the appropriate components and/or jumper wire together and get the solder to stick to the copper and components.

Where are you seeing "a T in a wire"?

The 7805 is typically in what's known as a TO-220 package, with the heat sync on the back. From the front (with the writing), it should be oriented like this:



On the buttons, use a multimeter to test, but each pair of legs are connected to eachother. You can either use one of each or both, but be sure to get the right ones.

Shorting D2 and D3 with solder is fine. Wire to D2 to D3 is electrically equivalent to wire to split to D2 and D3.

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Oh and PM me if you need more help on this type of stuff - its not very constructive to this thread, its just general circuit building. Glad to help, just don't want to clog up the thread with unrelated stuff...

[Spiffed]

The idea of a phone cord is actually quite enticing. terminating one end is a simple matter of including a 4p4c jack on the MPGuino and terminating the other end should be doable with a generic wall-box (like this one) and run what-ever type of wire from the wall-box to the Injectors, GND, Battery, VSS. Then a simple male-male phone cord can run through the firewall, in tact and sheathed. Should make for a very clean install with an easy to remove connector.

[Axaday]

I've been trying to test everything before wiring the LCD to the rest of the circuit and I've become alarmed. Should I be getting a little current between various pins of the iduino?

[wyatt]

Originally Posted by Spiffed

...a simple matter of including a 4p4c jack on the MPGuino and terminating the other end should be doable with a generic wall-box (like this one)...

The missing link! I looked into using a phone cord, but the wires are so flimsy I was having trouble stripping the ends, but this would eliminate all of those problems entirely... would the kit be able to have a phone jack attached? also, could a box like the one you suggest be included, just so we don't have to go find one elsewhere?

[Spiffed]

Yes, I have about 1/2 million 6p4c and 4p4c connectors laying around so they'll be included They're through hole with tabs, so it's just soldering.

Since the little boxes are like $0.70 it should be very possible to include them too ... that solves a major design issue for me.

[wyatt]

I got my iGuino all installed into the car (it's been waiting for me to do the in-car connections for weeks) and took it for a short test drive. It started right up and ran like a charm until I came to a stop, the screen went black and wouldn't come back on. It shouldn't have timed out since the car was still running. The backlight came back on when I started from a stop later during the drive, but the numbers weren't changing (like it locked up). The IM reset when I touched the area where I have the large cap and the 7805, but nothing would update. Anyone else run into this problem? Could it be that my large cap being 470 is just too large, or is it more likely that I botched my soldering somewhere? Now that I know it's working, I will be posting pictures of the buildup soon. I am pretty stoked that everything worked when I started it up!

update:
I have been running it for a few trips (to work, home, to the store) and no more glitches. The only thing I changed has been display brightness (at brightest setting). I think I will switch that back to the 42 setting (lightest backlight-on setting) and see how that goes. Hopefully I don't have to have the brightness cranked, because at night, this thing is seriously bright, even at 42 (so I am adding 10 and 20 settings to the new upload and we can test those out). The speed can be a bit jumpy (perhaps v0.71 will fix that), but nothing I couldn't live with. I can't wait to have a way of reading RPM in my car! Both cars that I have owned have been 5-speed-manuals, and neither has had a tach... so even if it isn't exactly on, it will be cool.

EDIT
I think there has to be a lose wire somewhere... I was cruising along last night and came to a bump in the road and the display went off instantly. I noticed that the yellow light on the iDuino was still lit, so I didn't lose power from the car, just somewhere in my setup. Will have to poke around with a multimeter when I get the chance, maybe just re-touch all the points with a hot soldering iron.

[wyatt]

Hey all,
I posted a lot of pictues of my build on Post #1 of this thread. Hopefully it is useful to people. I also changed around almost everything that was there, and made it more "instructions" like, and will continue to update it as I change things. Hope you like the pictures!

Oh, and let me know if I am missing something that would be useful, I want this to be more or less a place where someone that had no idea how to build one could go, and almost have a "step by step" tutorial. Thanks.

[wyatt]

Also have added pictures of an enclosure I made. It fits everything inside... it's tight, but that's the point isn't it?