I'm currently designing a piece of hardware to do real-time engine health/status datalogging and display. I was hoping to gauge interest in such a device. If no one is interested, I'll just build one for myself. If there is sufficient outside interest, then I might consider making it into a 'kit' of some form. Initially, I'm planning to make it compatible with the Z, but the design is general-purpose enough to adapt it to just about any other car out there.

In the initial design, I'm hoping to support up to 6 analog inputs, 2 PWM inputs, and 4 digital inputs. This is flexible. Data capture can go up to 100 Hz, which I think is plenty sufficient to monitor engine health. It will have an RS232 serial interface so it can connect up to a laptop for logging. It will also have a display.

I have two ideas for the display:

1. Reverse engineer the Nissan digital gauge that we currently have in the left-most stock gauge position. If I could successfully control one of these gauges, we could replace the somewhat useless battery voltage gauge with a second digital gauge that displays engine status information. I don't know how easy it will be to reverse engineer this gauge, however.

2. Use a 128x64 backlit graphic LCD to show lots of engine parameters at all times. You could mount it pretty much anywhere. I'd probably put mine in the empty nav unit slot.

Either display would have at least one LED warning light that would alert if some engine parameter goes outside of the acceptable range.

Alternatively, you could operate with no display, and just log the data into a laptop.

I'm still in the design phase.. I'm just hoping to see what everyone thinks of the project and if anyone might be interested in something like this.

Signals to monitor:

- Air/fuel (via a wideband O2 setup)
- Throttle position (TPS)
- RPM
- Injector pulse duty/width
- Intake temp
- Coolant temp
- Oil temp
- Exhaust gas temp (EGT)
- Crank angle

 

comments? questions? suggestions?

 

http://www.autotap.com/

 

Instead of going the hardware route, how about this http://www.scantool.net/software.htm? Try and get a open source version of the OBDII software and then use that as your platform. Then instead of the LCD screen in the NAV compartment, you could have, like some of the Z's out there, a custom in-car pc that does more than give you engine feedback. Just a suggestion.

 

I'm not very interested in an in-car PC. I'd rather not weigh the car down with a bunch of computer equipment I don't need..

most importantly though.. this is leaps and bounds beyond what is available with OBD-II. I'm talking about adding more sensor sender modules to the engine to measure various temperatures, and most importantly, wideband O2. I want to constantly monitor the Air/Fuel mixture to make sure the car isn't running lean. When I eventually add turbos to the car, I want to install a MAP sensor so I can read the boost levels as well.

If I build this thing as I envision it, it will make OBD-II look like a toy.

 

one last call for comments..

A few people say they're "seriously interested," but I haven't really heard any design suggestions. I'll make posts to update as I make progress in the design and construction.

 

Well, you kind of already got all of my suggestions through email. I voted seriously interested.

 

Personally I really like the the MoTeC ADL unit (sweet), but geeze it costs >$4000 , not including a WBO2. A cheaper clone of this unit would be a huge seller.

http://www.motec.com.au/disp.htm

Any " ideal" datalogger/display needs more than just the OBD2 scan inputs. Need WBO2, EGT, etc.

I have a G35 , so hi-jacking the Z gauge wouldn't frost my cookies.

 

I too am totally not down with an OBD2 based datalogger...hell, I got that on my Palm Pilot,a nd it is seriously lacking for anythin more than clearing check engine lights.

azrael - i am going to PM with something you may or may not know of that is out for other cars......

From a design standpoint, I would love for it to moniter knock, and fuel trims.

An LCD screen is cool with me.....would be much more useful I think than the small factory guage.

 

I think chazzg has a similar program for his in car PC.

 

unless he has purchased or designed a PCI card that does datalogging, then he's probably using OBD-II, which is fairly useless unless you just want to check your emissions systems and some other minor data.

The real thing that matters is A/F ratio, EGT, and timing. The rest is icing on the cake. OBD-II won't tell you a whole lot about any of those things.

I want to be able to tune my engine on the street, myself, and be 100 % sure that I'm running safely at all times. That isn't possible with out something like this.

Thanks for the input everybody. It currently looks like I'll go the backlit LCD route and also support logging via RS-232 to a PC. The PC could also have a display mode, for those of you with in-car PCs and whatnot. If this looks popular, I'll see what I can do to make the package clean and worthy of installation into people's cars. (i.e. not quite so cheap and DIY)

I'm hoping to come up with an aluminum enclosure for the electronics and a separate one for the LCD with a nice interface cable.

My other main issue is setting up the interface with the sensors. I'll need to tap the ECU harness for sure. Having the real connectors to mate with the ECU would be cleaner and easier to install, but I'm not sure where to source those yet. I need to get a copy of the service manual so I can find part numbers on those connectors and hopefully come up with a source.

 

You may also want to consider a few digital Inputs for things like monitoring the knock level output of a J&S etc. Woudl beat the hell out of a crude color bar LED.

 

that should be pretty easy. The more I look at it, I think I'm going to split the LCD and data acquisition equipment and use two separate microcontrollers, so I will have more processing power dedicated to monitoring inputs. This also allows me to read more signals. I think I might bump it up to 8 analog, 2 PWM, and 8 digital. I think 18 total inputs should be plenty to do fairly serious datalogging. The whole thing should be fairly configurable, so you can choose what kinds of inputs you wish to monitor.

NOTE: Unfortunately, my current design does not allow for internal logging into onboard memory. To do so would require a much more complex design, and I'm not really willing to do that unless this looks like the project has good commercial possibilities. If that turns out to be the case, I'll consider designing a PCB and using more powerful equipment with a few MB of DRAM on board to store data.

 

If you want to squirt multiple channels of telemetry out the serial proto towards a laptop etc, you may want to consider a USB port rather than RS232. Some of the lower end IBM PPCs provide a USB port and cost <$30. Granted not a $2 micrcontroller.
Also if you limit your design do the User interface you can already buy USB based data aquisition pod from many vendors. Iv'e seen a few 8-16 I/O USB devices for as low as $150.

 

Sorry , I posted a little mis-info. The general IBM PPC devices come with I2C and MII (ethernet). Ethernet , though gross over-kill is still pretty cheap . On another note:

If you want to avoid hardware design altogether , and just write SW . Using a PDA and DAQ pod may suffice. See:

http://www.bb-elec.com/palm/welcome.asp

 

Am seriously interested; so when can we expect to see a prototype; and a production model? I am presently in the market for gauges, monitors with wideband oxygen sensors.

PMed my wish list in addition to current list. I am presently considering the FJO system

Thanks
G

 

Dont' know whta they cost, but this could be a sweet "all in one" motherboard for your DAQ project.

http://www.dpie.com/littleboards/hercules.html

 

azrael:

what do you envision the cost of such an undertaking? I have no idea if it would cost us $5 or $5,000. Can you give us a ballpart figure/range?

Jeff - zland