Homebrew digital boost/vacuum gauge sneak peek

[nihil]

I miraculously ended up with some free time this evening, and finally got around to starting my boost gauge project. The display is the exact same size as the opening for the change/card tray so that is where it's going. I don't have the sensor in my hands yet, so I have a potentiometer filling in for it (ADC is the same as the +/- 30psi sensor I plan on using).

Here it is with a neutral signal (equal to atmospheric pressure):


Here is a shot reading 15psi after a peak of 22psi, and a peak of -8psi vacuum:


Reading -4psi vacuum after a peak of -9psi vac:


And as an added bonus, it's going to disable that pesky ESP every time I turn the car on :) :


Future versions might include meth/water injection management, and boost control. But for now, its just a boost/vacuum gauge that automatically disables ESP.

[7speed]

okay when they are mass produced, I have to be the first get one

[nihil]

If there is enough interest I could maybe see doing a limited run of them, but realistically it would be more expensive than some of the commercial offerings out there.

I'm also not sure how well it's going to fit behind the dash. The display portion itself is the ideal size for that opening, but the controller board attached to it is a bit larger, and I don't know what the back of that trim piece looks like yet. I might have to Dremel it to get the display in a good position.

[MikeWasHere05]

damn I had a long reply but lost it. Look up the inkjet method for PCB printing. What kind of uC are you using? I'm an AVR guy myself.

[nihil]

Mega8, and I usually use perfboard for prototyping/one-offs, but I do have a laser printer here and the materials to etch. That wont help with the size of the controller board mounted to the display though, it comes attached, and uses those obnoxious conductive rubber strips to tie the glass to the board, with it held down by that black frame. No chance of splitting them up.

[NiveK1970]

great, now make it to where it installs in the card holder slot so that it flows and looks OEM and ill be wanting it for sure :)

[A4ringedONE8T]

And how the hell did you know how to make that work?!?!

[sailor]

I have been wondering why one couldn't be hooked up to the radio feed, seems like a perfect place to have the display. If the radio can feed CD and track to the dash display then it seems this would be quite doable, just need to figure out the interface.

Nice work BTW.

[martini]

I got a secret for you... boost can be displayed in your AC controls...

shhh

[sailor]

I got a secret for you... boost can be displayed in your AC controls...

shhh

Care to share a little more about this?

[RLB6]

I did a custom digital boost/vacuum gauge in the lower corner of my rearview mirror but the electronic boost sender has since failed. Was really nice when it was working. Where are you picking up your readings from? CAN BUS??

If there is enough interest I could maybe see doing a limited run of them, but realistically it would be more expensive than some of the commercial offerings out there.

I'm also not sure how well it's going to fit behind the dash. The display portion itself is the ideal size for that opening, but the controller board attached to it is a bit larger, and I don't know what the back of that trim piece looks like yet. I might have to Dremel it to get the display in a good position.

[martini]

I did a custom digital boost/vacuum gauge in the lower corner of my rearview mirror but the electronic boost sender has since failed. Was really nice when it was working. Where are you picking up your readings from? CAN BUS??

hes going to put in a pressure sensor it sounds like... there is already a boost sensor which transmits on CAN which is probably easier to use

[jcg05c]

^ shhh? explain haha please

[dougyfresh]

Nice idea. I wish I knew more about electronics to tackle something like this myself. My mind works better with gears. EE classes were difficult but I figured out the basics.

Even better is if you can pull all that data off the CAN Bus so you don't have to rely on additional sensors. It can be done. I know someone developing a device that can read anything off the CAN you want and display it on a digital read-out. I might be one of the first to receive such a device from said individual.

[[email protected]]

That is a nice setup you have made there.

[nihil]

Thanks all for the kind words, that'll teach me to start a thread then go take a nap.

great, now make it to where it installs in the card holder slot so that it flows and looks OEM and ill be wanting it for sure :)

It's just a one-off homebrew project for the moment, so don't expect to see them on your favorite tuners website anytime soon. A buddy asked me this morning about the possibility of a kit, or just a pre-burned microcontroller and parts list type deal, which would be a lot more likely.

And how the hell did you know how to make that work?!?!

Insomnia gives you more time for hobbies ;)

I have been wondering why one couldn't be hooked up to the radio feed, seems like a perfect place to have the display. If the radio can feed CD and track to the dash display then it seems this would be quite doable, just need to figure out the interface.

Actually another red display will be filling up the cup holder slot eventually. It will display ID3 information from the currently playing track on the embedded Linux machine that will be stuffed in the glovebox. I picked up a car2pc interface that lets you interface a carPC as a cd changer. It will also have a small touchscreen display that will be folded away most of the time (unless I'm mapping things or datalogging via vagcom), but the LCD will be the primary interface.

I got a secret for you... boost can be displayed in your AC controls...

I'm listening :)

I did a custom digital boost/vacuum gauge in the lower corner of my rearview mirror but the electronic boost sender has since failed. Was really nice when it was working. Where are you picking up your readings from? CAN BUS??

I'll be using an industrial grade amplified differential pressure transducer at +/- 30psi. It's temperature compensated from 0 to 50°C (32 to 122°F) with an acceptable drift outside those extremes. I'm not locked into this sensor though, so if anyone has recommendations on a good automotive pressure transducer I'm all ears.

I wanted to stick with a standalone unit instead of tying it into the bus so I could use the same design on other vehicles. Also, my `02 does not have CAN, it speaks KWP2000/ISO9141, and if I want to measure via that bus, the carPC with vagcom will do well.


dougy/martini: no CAN do :(

winston: thanks :)

[nihil]

Finally got around to picking up a sensor today, if I can find some time this weekend, I'm going to finish up the programming (convert vac to inHg, add a button to clear last peak, and another button to switch between mbar and psi/inHg), and weather permitting, get it installed in the car.

Even better is if you can pull all that data off the CAN Bus so you don't have to rely on additional sensors. It can be done. I know someone developing a device that can read anything off the CAN you want and display it on a digital read-out. I might be one of the first to receive such a device from said individual.

Last month I picked up some parts to start a project similar to this. I found what looks to be a pretty reliable means of speaking most popular OBD protocols, and want to build a small digital dashboard/scope type thing. As much as I end up working on other peoples cars, it'll be a neat diagnostic tool to have around. It could also easily be adapted for an in-car display.

I got a secret for you... boost can be displayed in your AC controls...

You sure are good at keeping secrets... Not even a hint?

[AudiA4Turbo22]

Bump For An Awesome Homebrew Project!

[diagnosticator]

The '02 has CAN, Powertrain, Infotainment and Comfort/Convienience CAN busses. But is not CAN OBDII diagnostics capable.

[nihil]

Bump For An Awesome Homebrew Project!

Thanks!

The '02 has CAN, Powertrain, Infotainment and Comfort/Convienience CAN busses. But is not CAN OBDII diagnostics capable.

Interesting, all the info I had seen pointed to them not speaking CAN at all until later. Do you know what revision?

[converted2audi]

cant wait to see what that will look like when its actually installed......great work, wish i knew how to do stuff like that....

[quat]

Bump because this is an awesome project and martini has everyone reading...

[JohnnyG]

I got a secret for you... boost can be displayed in your AC controls...

shhh

Hey, I've seen b5 s4's w/boost displayed in the the cluster DIS (I'd love to do that) but in the a/c control head? you gotta share.......

[dirtyserby]

i wanted to do this myself, this is the pressure xducer i researched and planned on using.

MPX4250A

http://www.freescale.com/files/senso...t/MPX4250A.pdf

i think its something like 20-30$

[nihil]

i wanted to do this myself, this is the pressure xducer i researched and planned on using.

MPX4250A

http://www.freescale.com/files/senso...t/MPX4250A.pdf

i think its something like 20-30$

Well, that's a head start on where I'm at with the OEM T-MAP (pressure+temp) sensor package. I can't find a proper datasheet, but did find a non-orientation-specific pinout, so I'll have to wait until the rain lets up to go test the harness for ground pin position (Jeep is hogging the garage).

[dirtyserby]

Well, that's a head start on where I'm at with the OEM T-MAP (pressure+temp) sensor package. I can't find a proper datasheet, but did find a non-orientation-specific pinout, so I'll have to wait until the rain lets up to go test the harness for ground pin position (Jeep is hogging the garage).

good luck

very interested to see how this turns out!

[Overboostin]

That is totally rad! If you could let me know how to do that for water/meth management that would be amazing.

[AudiA4Turbo22]

i say once u figure it out u should patent it!

[nihil]

That is totally rad! If you could let me know how to do that for water/meth management that would be amazing.

Yes indeed that would be amazing. I still have a bit to learn about meth injection before I start coding for it.

I picked up a dual nozzle meth kit not too long ago, just haven't had time to install it. After I get that and the FMIC installed, and put a few miles on it, I'll have a better idea of what kind of programming it needs.

i say once u figure it out u should patent it!

I'm not doing anything even remotely patentable. All of this has been done before, I'm just doing it the hard way

[diagnosticator]

Yes indeed that would be amazing. I still have a bit to learn about meth injection before I start coding for it.

You can get some insight regarding IC water spray controller logic and water injection control logic here:http://www.autospeed.com/cms/A_110368/article.html

[nihil]

Great reading there. Thanks for the link! There are some other pretty good articles there too.

[VZWalex]

BUMP for a sweet ass project !

[AudiA4_20T]

rediculous... Id love to have that

[nihil]

Got a little more work done. The sensor is a 4 pin T-MAP type, which is a MAP and IAT effectively combined into one package. The odd part is, when I had the harness in the car apart to get the proper pinout, the thermostat feature is not used at all, only three of the wires are connected +5V, Ground, and signal from the pressure transducer. Adding IAT display to the gauge would be fun, but I have absolutely no idea what the temperature range is on this thing. Anyone out there have an idea?

I thought it was a bit strange that they would choose a more expensive sensor, only to use half of it, and then require a dedicated IAT sensor attached to the manifold, adding even more cost. Maybe it's just a quirk on the `02?

Sorry for the crap quality phone pics, battery on the digicam is dead. First up is the new startup screen (right before it disables ESP):


And the new display showing boost in psi with peak holding, vac in inHg with peak holding, and on the right in millibar:

[3.0L AUDI A4]

Holy goodness.. that is amazing work!!!

[nihil]

http://www.metacafe.com/watch/132054...l_boost_gauge/

[nihil]

Anybody know how to get that stupid card drawer out?

I've got the radio out, and it looks like it's going to be a bitch getting the LCD in that spot, but I won't know for sure until I can get the damn drawer out. I'd like to make it a reversible mod, but I think its going to require the mighty Dremel.

[nihil]

Got a good part of the dash/console off, but still couldn't get the housing for the card drawer out. I did manage to rip the drawer itself out, breaking it in the process, and getting this particular display in there will definitely require some Dremel time. I buttoned it back up for now, if anyone has instructions for getting that drawer housing out it would make things a lot easier. Else I might try and attack it while its in the car tomorrow.

[JohnnyG]

Got a good part of the dash/console off, but still couldn't get the housing for the card drawer out. I did manage to rip the drawer itself out, breaking it in the process, and getting this particular display in there will definitely require some Dremel time. I buttoned it back up for now, if anyone has instructions for getting that drawer housing out it would make things a lot easier. Else I might try and attack it while its in the car tomorrow.

pop off the upper console trim (above the card drawer and cup holder and below your decorative dash trim:carbon, metal,wood..whatever u have) the best way to get it out is with a plastic trim tool or carefully w a flat head screwdriver and a rag. pry it from the sides a little at a time and it will pop out. Then you will be able to access the area above the card holder. There are tabs on the housing which you will have to push down (a pic works well) you may have to push 'em down while pulling the housing.

[nihil]

Thanks! I was going from the bottom up.