Rectangular aftermarket gauges?

[cleeves]

Seems like the debate about gauges for the E24/E28 has been beaten to death. The lack of an oil pressure, oil temp, and voltage meters cause owners to really wonder why BMW didn't put them in the cars originally. Yadda yadda. People have put them in the ashtray and where the vents are, or other odd places.

Here's a different idea that does not seem as beaten to death.

Why not cut out the middle rectangular section of the instrument cluster and install a column of rectangular gauges like the fuel level and water temp? There seems to be enough room for 2 more gauges. Maybe 3 if you modified the water and fuel temps. Forget the silly worthless warning/inspection lights, just cut that out to get more room. Maybe even ditch the green blinker indicators or find a different spot for them.

If analogs wouldn't fit then maybe digitals would work. Some red LED gauges would look cool with the red backlight.

For a point of reference:



Besides being a huge complicated undertaking, any thoughts?

Henry

[Frybrid 524td]

Have you opened a gauge cluster up? If not, take a look inside one and think about how you'd get all that to fit in there.

[cleeves]

Have you opened a gauge cluster up? If not, take a look inside one and think about how you'd get all that to fit in there.

No i haven't. Good point.

If you took out the stock water temp, fuel, and middle lights completely I bet it would free up a lot of space. Digital gauges might still be possible. Maybe a fuel one that read how many liters were remaining and temp gauges in degrees Celsius. SI units FTW.

If you had the D/A converters and their respective circuit boards located somewhere else, it would seem that all you would have to have in the middle of the cluster is a slick digital panel with a ribbon cable running from it.

I need to get a cluster from a junker so I can tinker with this. Anybody got a cheap one?

Henry

[Paul in N FL]

You can view the liters remaining by pressing 1000 & 1 on the OBC.

[Shawn D.]

If analogs wouldn't fit then maybe digitals would work. Some red LED gauges would look cool with the red backlight.

E28 gauges don't have any backlighting.

[cleeves]

You can view the liters remaining by pressing 1000 & 1 on the OBC.

Sweet, I forgot about that! That means I'd just have to run the correct wires from the OBC back to the main instrument panel and not have to worry about a D/A converter.

I've seen digital gauges for the temps and voltages in other cars installed aftermarket, so if the correct parts could be collected this might turn into a serious project. Or attempt at one. I'm not an electrical engineer but I can solder and use a scope with some limited ability.

I guess another problem I'd run into is finding a single digital panel or matching ones for each gauge. I'll check with my local discrete components electronics store this week and see what they have.

What if I bought something like this and swapped the digital readout for a different one that would match, and then routed the wiring?



Henry

[cleeves]

If analogs wouldn't fit then maybe digitals would work. Some red LED gauges would look cool with the red FRONTlight.

E28 gauges don't have any backlighting.

Good point. Fixed in quote. Lefty loosey righty tighty backy fronty.

aaaaaghh!


Henry

[Shawn D.]

If analogs wouldn't fit then maybe digitals would work. Some red LED gauges would look cool with the red FRONTlight.

E28 gauges don't have any backlighting.

Good point. Fixed in quote. Lefty loosey righty tighty backy fronty.

aaaaaghh!

[cleeves]

http://cgi.ebay.com/0-28Red-LED-3-digit ... 733wt_1404

[turbodan]

Seems to me we recently had a similar thread about ratchet shifters.

[cleeves]

Saw this on another board... where the autotragic lights are mounted.


What a great idea. Didn't even have to cut out the temp and fuel gauges. You might even be able to fit in a digital boost gauge for a turbo car if you fitted smaller numbers or squeezed the text.


turbodan, tell me you wouldn't take that over a ratchet shifter!


Henry

[JohnH]

Saw this on another board... where the autotragic lights are mounted.


What a great idea.

Yes it is. Mind sharing where you saw that. I've been toying with doing this for some time.

[Frybrid 524td]

Mind sharing where you saw that.

http://newling.no-ip.com/rep/

[mooseheadm5]

There are a couple of people I know that are capable of making that happen. The display in place of the auto trans lights is really the best way to do this. If you can get me specific details about what you want I can talk to them.

[ahab]

Paul, that is bad ass. I would be interested in oil pressure and temp there too.

[hinterländer]

Saw this on another board... where the autotragic lights are mounted.

What a great idea. Didn't even have to cut out the temp and fuel gauges. You might even be able to fit in a digital boost gauge for a turbo car if you fitted smaller numbers or squeezed the text.

Henry

Man that is a schweeeet idea. definitely worth a loook

[shagrath]

subscribed. very kewl!

[cleeves]

There are a couple of people I know that are capable of making that happen. The display in place of the auto trans lights is really the best way to do this. If you can get me specific details about what you want I can talk to them.

Is there a way that you could get a hold of the schematics/wiring diagram for this if there is one? Even a basic how-to, or a parts list or something would help. FYI, I want something just like that picture. This thread may transform itself into a disassembled E24 dash in my driveway and burned fingers from the soldering iron.

Best,
Henry

[hinterländer]

I visited the website mentioned and the only thing I was able to find was the PCB blueprint. Seems like that site is no longer active, but it shouldn't be terribly difficult to design a circuit. From what I can gather the functions most desirable are:
-Oil pressure
-Oil temperature
-Coolant temp
-perhaps an air/fuel ratio meter?

Aside from the circuit design itself how "ready" is the car to accept this mod? obviously there is already a sensor for oil pressure, hence the idiot light. Oil temp? there's already a coolant temp sensor/gauge already, the only reason I see to incorporate would be to see precisely what the temperature is. Does the DME provide a means of measuring air/fuel ratio? That perhaps is the single best reason I see of designing/building such a display. Any thoughts I may have missed?

[tangerineman91]

Here's my list of desirable functions.

-Oil pressure
-Battery Voltage
-AFR

[Xenocide]

I'm in the middle of writing some code for an on board computer based on a little PIC18F micro controller.

Ideally, when it's done, it'll interface with megasquirt to output AFR, CLT, MAT, MAP, etc. and also have a couple sensors for oil pressure, oil temperature, and voltages for all the various buses I have wired in. What info to be viewed will be selected with the OBC buttons (the OBC itself will no longer function).

I had planned on outputting the info to a 16x2 or 20x4 LCD, I wonder if it would fit in there. Great idea!!!

I'll be sure to post a write up if (when) I finish mine. If there's any interest I may have a run of PCBs done. Right now my budget for this little gadget is around $30~40 in parts, the cost will likely go up when I move from perfboard to PCBs though.

[hinterländer]

That sounds nice Xenocide, but I'm not quite sure a 20x4 would fit in that area, but the 16x2 should. The height of a 16x2 is about the same as a standard 7-segment led, which is what is shown in the picture. If I'm lucky, I may be able to finagle an instrument cluster from a junkyard I've been to nearby that has one e28 in it (one of only a few good parts left on it), otherwise I'm operating on the temporary assumption (based on the picture cleeves introduced us to)it's about .625"-.687". I'm hoping to make use of the Bosch DME (though I would LUV to replace it with a VEMS ecu), so I have a feeling I'm about to become reacquainted with the good ol ETM

@tangerineman91, those are the three functions I feel are most desirable as well, and the one's I'll be working towards implementing.

[stuartinmn]

Saw this on another board... where the autotragic lights are mounted.

Dang...I thought of that myself some years ago, but never did anything about it. I've been scooped again.

[abdoosh00]

7-segment is much better and clearer. a 16x2 will be too small to see without getting ur head closer to the cluster, u dnt wanna do that while driving.

I think battery voltage and coolant temp or oil temp are easy to to read directly from sensors. for the AFR you will need to know the "air volume" to resistance relation read from AFM flap, could be done but need sum kind of air measurement tool for correct calibration.

[Xenocide]

7-segment is much better and clearer. a 16x2 will be too small to see without getting ur head closer to the cluster, u dnt wanna do that while driving.

I think battery voltage and coolant temp or oil temp are easy to to read directly from sensors. for the AFR you will need to know the "air volume" to resistance relation read from AFM flap, could be done but need sum kind of air measurement tool for correct calibration.

I'd get AFR through megasquirt (or directly) from my wideband. Battery voltage and coolant temp are indeed pretty easy, though I need to install a sending unit for oil pressure and temperature.

And as for the difficulty reading the 16x2, I had figured I would use two bar gauges or some such thing to make quick reference easier. I haven't even hooked it up yet, so this is all just words right now, but I'm using the blue/white ones so the contrast is remarkably good.
We'll just have to see once I get the prototype finished. It'd be pretty easy to do 7 segments as well, I just got some i2c 4 digit 7 segment drivers I've been meaning to play with. It'd just be more difficult to keep all of the output straight.

[abdoosh00]

If I was working on it I would do it to work on both on MS and motronic, taking a reading from the wideband is good enough, but wont work on pre-86 cars as they dnt have one.

not sure wut you mean by keep all of the output straight though!

[hinterländer]

7-segment is much better and clearer. a 16x2 will be too small to see without getting ur head closer to the cluster, u dnt wanna do that while driving.

I think battery voltage and coolant temp or oil temp are easy to to read directly from sensors. for the AFR you will need to know the "air volume" to resistance relation read from AFM flap, could be done but need sum kind of air measurement tool for correct calibration.

x2 on the 7-segment. I still am trying to see the wisdom in oil temp though. Already have a coolant temp gauge, too. So that still leaves battery voltage, oil pressure, and AFR. My '87 uses Motronic 1.0, so I'm still using a narrow band O2 sensor which isn't as precise as wideband, so I'm still debating the usefulness for a stock DME (perhaps to monitor the condition of O2 sensor?); but people using tuner chips may find it useful. AFAIK, there is NO oil pressure sensor on this motor (M30B34) from the factory?

[Xenocide]

If I was working on it I would do it to work on both on MS and motronic

Well, it'd be great to use it on MS and motronic, but motronic has no serial connection. You could collect data from individual sending units, but you'd have to splice into the factory harness, and in the interest of saving pins on the controller I'd want to use serial to get 80% of the data using only 2 pins. Plus I have been toying with the idea of programming maps over serial (purely a pipe dream now, but certainly possible).

taking a reading from the wideband is good enough, but wont work on pre-86 cars as they dnt have one.

I figure anyone who is interested in realtime AFR has a wideband...

not sure wut you mean by keep all of the output straight though

I meant that without labels it'd be difficult to determine which number is which. You could have LED indicators or something, which would work okay I suppose, but it seems unpolished next to a full display*
*If it's remotely readable


As soon as I get a working prototype I'd love some ideas to make it more usable by more people, but right now I'm just playing with my own setup. Honestly this thing would be so much damned work for other people to install, it'd probably be more trouble than it's worth for most people, but hey it could be cool right?

EDIT:

AFAIK, there is NO oil pressure sensor on this motor (M30B34) from the factory?

Correct. Oil pressure switches were, but no analog sensors.
EDIT #2: Same goes for the m20

[abdoosh00]

As soon as I get a working prototype I'd love some ideas to make it more usable by more people, but right now I'm just playing with my own setup. Honestly this thing would be so much damned work for other people to install, it'd probably be more trouble than it's worth for most people, but hey it could be cool right?

Cool...definitely.

Trouble...what isnt with a 25 yrs old car .

If you get smthng workin ill be happy to see. If anythng could be adjusted ill try to help as well. PIC18F you said, using Assembler or C?

[Xenocide]

Been working on it in C (C18 compiler). I've not done much C before, and never worked with PICs so it's been slow going, but it's fun. I had half a mind to just ditch the PIC and use an arduino, but that'd be just way too easy (and too few I/Os to play with)