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Discussion Starter · #1 ·
original post:
http://forums.swedespeed.com/zerothread?id=115469

Custom Oil Temp/Haldex Temp/Photo Slideshow Gauge in the making! Using...PICAXE uController and 4D system's OLED (96x64)

Here's what I have come up with so far:

The OLED display needs to be powered down properly so I've programmed the PICAXE via an interrupt to initiate a power-down sequence when the ACC line goes low. When ACC line goes low, the PICAXE has power for 7 seconds (using a cap, relay and some resistors) and in this time it initiates the power-down sequence to the OLED.

You can see the pics and vid of the project working without any thermo sensing device. In the video you can see that the gauge alternates between a temperature screen and 1 of 14 random R images (all of which I've snagged from the forum, thanks all!). There is also a random splash screen upon startup!



http://www.caschy.com/coppermi...a.AVI (don't mind the stupid shutter noise or Dancing with the Stars in the background
)

Next up, trying to find a thermocouple to read oil temp!
 

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HOLY FREAKING AWSOMENSS

I wish I was that smart to figure this out lol
 

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Discussion Starter · #4 ·
Not sure what to use. I need something relatively easy to interface like 10mv/degree or something.

How about if I used some sort of plug or fitting that I could drill out and insert a thermocouple, like the "beverage" model from here:

http://www.thermoworks.com/pro....html
 

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Re: (juve021)

Boost data possible??
 

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Re: (Short Circuit)

Quote, originally posted by Short Circuit »
Boost data possible??
+1

Boost/vacuum, oil pressure and exhaust gas temp. http://********************/smile/emthup.gif
 

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Re: (-Pascal)

I might not be Helmut, but I want to mate with your OLED display.

Would an external temp sensor be adequate for fluid temps...? What about getting a temp sensor that can be inserted into a "tap" into whatever housing necessary? A proper tap and gasket w/ proper sensor should do the trick, no?

I only say this because I am drunk and listening to Dave Mathews, but I would probably say similar things if I were sober.
 

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Re: (Juve)

Juve, I have a lot of appreciation for your projects

I know you already have a boost solution in your car, so for those interested here is how I would do it

MAP sensor ->voltage follower (& possibly amplification-> -----------summing amplifier ->adc-> uc
barometric sensor-> inverting amplifier ------------------------------|^

this is pass one, and can be simplified a lot

a) by Tom Talpey's trick of using the boost sensor when car is off as a barometric sensor (but then if you change altitude as you drive you are screwed

b) if your uc has an extra adc channel you can subtract the atmospheric pressure inside it instead of my silly circuitry

c) d) e) I am sure others will point out ways to further simplify this.....

I am not drunk, but since it seems to be the theme, count this as a drunk post


Operational amplifier wikipedia

OPAMP apps wikipedia

boost (MAP) sensor info SS

Modified by FEO at 11:50 PM 3-23-2009

Modified by FEO at 11:53 PM 3-23-2009
 

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Discussion Starter · #11 ·
Re: (AthruC)

Quote, originally posted by AthruC »

Would an external temp sensor be adequate for fluid temps...? What about getting a temp sensor that can be inserted into a "tap" into whatever housing necessary? A proper tap and gasket w/ proper sensor should do the trick, no?

err like this one?
http://buyjpi.com/Merchant2/me..._Code
 

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Discussion Starter · #12 ·
Re: (FEO)

Quote, originally posted by FEO »
Juve, I have a lot of appreciation for your projects

I know you already have a boost solution in your car, so for those interested here is how I would do it

MAP sensor ->voltage follower (& possibly amplification-> -----------summing amplifier ->adc-> uc
barometric sensor-> inverting amplifier ------------------------------|^

this is pass one, and can be simplified a lot

a) by Tom Talpey's trick of using the boost sensor when car is off as a barometric sensor (but then if you change altitude as you drive you are screwed

b) if your uc has an extra adc channel you can subtract the atmospheric pressure inside it instead of my silly circuitry

c) d) e) I am sure others will point out ways to further simplify this.....

I am not drunk, but since it seems to be the theme, count this as a drunk post


Operational amplifier wikipedia

OPAMP apps wikipedia

boost (MAP) sensor info SS

Modified by FEO at 11:50 PM 3-23-2009

Modified by FEO at 11:53 PM 3-23-2009

Yeah I don't get this...are you sure you were drunk?

I haven't read the boost sensor thread but if its just a matter of x volts = x psi then why the need for the barometric sensor? You could feed the voltage into the uC (via an opamp, if required) and then do some interpolation/smoothing in the uC program/software.
 

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Re: (juve021)

Quote, originally posted by juve021 »
Yeah I don't get this...are you sure you were drunk?
maybe...maybe not

Quote, originally posted by juve021 »
I haven't read the boost sensor thread but if its just a matter of x volts = x psi then why the need for the barometric sensor? You could feed the voltage into the uC (via an opamp, if required) and then do some interpolation/smoothing in the uC program/software.

The problem is that the sensor in the car reads absolute pressure (aka Manifold absolute pressure, aka MAP), not boost which is the increase over atmospheric pressure. To be able to display boost you need to subtract atm pressure. (it's in that thread you didn't read
)

Also in that thread I posted a link to a basic small pressure sensor, which I believe could be used for this purpose. I didn't triple check all specs, so don't hold me liable to it


tiny pressure sensor (PDF)
 

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Discussion Starter · #14 ·
Re: (FEO)

Quote, originally posted by FEO »

maybe...maybe not

The problem is that the sensor in the car reads absolute pressure (aka Manifold absolute pressure, aka MAP), not boost which is the increase over atmospheric pressure. To be able to display boost you need to subtract atm pressure. (it's in that thread you didn't read
)

Also in that thread I posted a link to a basic small pressure sensor, which I believe could be used for this purpose. I didn't triple check all specs, so don't hold me liable to it


tiny pressure sensor (PDF)


Ah ok, understand now. Well the uC I'm working with has I think 4 or 5 ADC channels so its more than capable. Kinda stinx that I already have a boost gauge cause I would be MORE enthus'd about reading this parameter


I'm going to try to do oil temp first, then probably EGT and then go from there for others. I already have the opamp (AD595) picked out to work with.
 

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Discussion Starter · #20 ·
RE: juve021

UPDATE------

I received my laser cut gauge bezels today...trying to decide which one to go with. I think I like the brushed aluminum the best...oh and yeah, the black with black engraving didn't make it in shipping!


I guess from the first pic its hard to see but the first at the top is a matte black with white engraving, second is black shiny with black engraving and the third is brushed aluminum with black engraving.





Which one do you think?
 
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