DIY. combined boost, afr, knock, LCD gauge with future datalogger - progress report

[bebbetufs]

UPDATE: Shoddy mobile phone video of alpha version posted here. Please disregard the values shown. They will be tweaked.

Just a short progress report for those of you who have contributed to this project.

I am building a digital gauge with a red-on-black LCD to match the style of the existing instruments in my 951.

Phase two will eventually have full datalogging including GPS, but phase one will focus on getting the measuring and displaying of boost and wideband AFR up and running.

Currently I have the boost gauge up and running. It is based on the gauge in this video by Sean over at digiboost.com, but with a larger display which holds more info, and no colour change. (Sean's gauge can be fitted as is to our cars).

The LCD displays both numerical values as well as bar-graphs in the primary view.
The boost bar goes from left to right as boost builds and from right to left in vacuum. Looks really cool.

The AFR bar goes from a centre point to the left as the mix gets richer and to the right as it gets leaner. Both graphs are shown in the same view.

A secondary view will show max values such as:
Max boost on run, total knocks counted, max RPM on run, maxSpeed on run (disable for road use), and max G in 3 axis (yes i know but I want it )

Phase one will also have a menu system for setting user selectable values.
Input is controlled via a click nob/wheel with a central push button. A very simple and intuitive method. It works really well.

This is what I'm currently working on and the basic structure for the following is in place:

I will be able to set overboost, pressure units BAR/PSI, zeroing some of the counters etc. Phase 1.5 will have a customizable shift light system which can be stealth mounted.

There will also be user customisable alarms such as
overboost alarm, redline alarm and lean-mix alarm

I will update this post as I go along, but going will be slow at times as this is my first real programming project.

I will upload a video showing the LCD in action on my work bench by the end of the week.

Please feel free to post your comments, suggestions or questions.

This is the old thread where I asked for help getting started:

[bebbetufs]

I would like suggestions as to what would be a usable display range for the AFR
11-16?

[chally72]

10-18 is usually what a wideband gage range is.

What components are you using for this project? This seems like a very cool gadget.

[bebbetufs]

I would think the risk of detonation would be huge at 16. Would it not be better to have higher resolution in the operational window?

The most important is the UEGO inline wideband and an mpx4250 automotive pressure sensor. The platform is Arduino.

[chally72]

I have heard quite a bit about Arduino lately. If you know VB, C++, Fortran, etc fairly well, how hard is it to really pick that up and do useful things with the Arduino board?

Perhaps if you have a bar display, you only want to go up to 15? When you let off the throttle you'll see the bar shoot all the way in that direction, anyways.

[bebbetufs]

I would say it is really easy.
I only knew some very basic java when I started this, and I have been able to get along quite alright.

I'll start off with the full range.
I might make the range a customizable setting in the menu, but it takes a lot of math.

[chally72]

I read through your original post and I am really interested in this project now.

Question: for dummies, what is an external interrupt that you plan on capturing the knock signal with?

Can you maybe post up a list of sensors you got, and where you got them from?
Can you put up a picture of the gage in action right now?

The arduino stuff I've seen has just been displayed on a small LED bar. Is it possible to create something like a motec dash with these, or does the arduino only handle one thing at a time?

[bebbetufs]

The sensors so far are the AEM inline UEGO and the MPX4250 pressure sensor.
The Arduino can handle a lot at a time, possibly also a Motec type dash, but it would take a lot more work as think you would have to handle graphics which are very large, possibly too large.
You should ask your questions in the Arduino forum, I am really just a newbie teaching myself to program while keeping the task interesting and meaningful

Pictures will be up soon, but right now I'm troubleshooting, so it's really not presentable.

[chally72]

The more I read the more excited I am about that board.

Dakota digital is the premier maker of digital dashes for musclecars, classic cars, etc. Look at one of their dashes. Some simple blue number boards behind a tinted piece of lexan. And they charge 800 bucks for it! And then you need all the senders......

Post pictures bebbetufs! Besides a LOT of time, there doesn't seem to be much standing in the way of making a complete digital dash from a few LCD panels!

[bebbetufs]

Before spending all those hours you must research how you want to drive the panels. There are libraries for some tiny Nokia dot matrix panels, but nothing of that sort. Also consider how bright the panels must be to be viewable in all kinds of light. I don't think that Motec display is a common LCD which can be easily driven from arduino. It seems like a high contrast TFT or something to me and you would likely have to write your own hardware library for something like it. Also remember that normal LCD's are limited to displaying characters. To display neat graphics you need dot matrix displays. You could do this, but I don't think you would have time to actually drive your car. I think it's more feasible to simply have one LCD show some data in addition to the cars instrumentation.

[chally72]

I work at an aerospace company programming measuring machines for my day job. It means I write a lot of math in FORTRAN and also have to program the code that graphically represents the parts I measure, which range from turbine and jet engine blades to gears. Slick graphics stuff is pretty easy, if tedious, work.

I'll sit back and read up on arduino, and probably pick up a board to tinker with in a few weeks.

Good luck!

[bebbetufs]

Great news. If you want to go that route please start by checking what kind of workload the board can handle. I've heard that a gps system can really tax some of the boards.

Personally I prefer any system to be as stealthy as possible. I won't have my gauge on or in the dash at all, instead I'll have audible alarms that will go off I i exceed any of the thresholds I've set. I think I will hide the LCD will be behind the slider in the ashtray, or I might put it in the trim strip next to the cigarette lighter.

The shift light will be in the instrument cluster, behind one of the warning lights. The most important thing to me are the alarms as they can help minimize or prevent damage from say a stuck injector or a failed cycling valve or waste gate.

[bebbetufs]

update, or rather lack thereof. Progress has been lost due to more pressing matters. I'll post video as soon as it is ready.

[bebbetufs]

Video of alpha version posted. See first post.
Please disregard the values shown. They will be tweaked.

[billy mild]

Are you going to be selling these? Also where would you mount something like this?

[bebbetufs]

I am making it for myself at the moment, but if people are interested I might consider selling a few kits. I will need to test it properly first. The best place for it will be in the compartment below the stereo, but I'm also considering other options. Shift light will be in the instrument cluster, but this could be adapted.