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kerian159 Samba Member
Joined: February 24, 2008 Posts: 344 Location: Pensacola, FL
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Posted: Mon Jul 24, 2017 7:49 am Post subject: Arduino CHT, Oil temp, Oil Pressure |
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I got to wondering (looking at a DD for CHT) if I could make something that would be able to pull CHT from all four cylinders, Oil Temp from the standard oil sump plug, and the oil pressure from a double relay to read on an arduino that would then send all that info via Bluetooth to a old cellphone I had. The programming of it doesn't really look that difficult but the finding of the parts (CHT only) is giving me a headache. Does anybody have any idea of good thermocoupler parts that I could wire to a box under the back seat? _________________ 1976 Type II Westy P22
"Growing older, but not up!" |
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dwill49965 Samba Member
Joined: August 08, 2005 Posts: 1396 Location: Dartmouth, Nova Scotia
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Posted: Mon Jul 24, 2017 8:01 am Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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There is a bunch of info on thermocouple wire and sources from this link that you may find useful - the good old MGL Stratomaster!
https://www.thesamba.com/vw/forum/viewtopic.php?t=423765&highlight=stratomaster _________________ Darryl
--------------
'78 Westy, Boston Bob built 2.0 L, FI, MSD 6A
Meyer wrote: |
Lastly, you just referred to US citizens as 'Americans'. Exactly what kind of Canadian are you? From what continent? |
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a-marshal Samba Member
Joined: March 21, 2009 Posts: 270 Location: Toronto
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Posted: Mon Jul 24, 2017 8:18 am Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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I've been playing at making something similar, but I've planned to use an OLED display at first since I don't have any cell phones much less an old one.. the issues I've been dealing with are hardware related (and personal lack of experience related)
I've been trying these, the analog type K amps, they seem to work well enough..
https://www.adafruit.com/product/1778
I thought about these
https://www.adafruit.com/product/269
but there is a limit to how many digital I/O pins are available..
I've tried all sorts of type K wires including a set from Dakota Digital and sets from ebay and they are pretty much the same.. in testing I seem to get around +/- 3-5 degrees C.
I had one set up working perfectly in testing but I could not see the Back-lit LCD in daylight... _________________ -Ob. vehicle info....
1973 Westy w/ '74 1.8 liter / PDSI (type3?) carbs / 009 distributor / pertronix |
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mikedjames Samba Member
Joined: July 02, 2012 Posts: 2736 Location: Hamble, Hampshire, UK
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Posted: Mon Jul 24, 2017 12:24 pm Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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The OLED screens are quite bright.
I made some up with the 1.3 inch 128x64 screens..
http://www.thelatebay.com/index.php?threads/digita...mfd.65973/ _________________ Ancient vehicles and vessels
1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.
1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy |
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a-marshal Samba Member
Joined: March 21, 2009 Posts: 270 Location: Toronto
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Posted: Mon Jul 24, 2017 1:08 pm Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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Mike.. That is seriously impressive.. I am using the same OLED screens. I started out with an LCD but couldn't read it in daylight.. went to a TFT screen with the same issues. I wanted to change the screen colour based on engine conditions .. green - yellow - orange - red but it sort of defeats the purpose if it is only viewable at night... _________________ -Ob. vehicle info....
1973 Westy w/ '74 1.8 liter / PDSI (type3?) carbs / 009 distributor / pertronix |
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tootype2crazy Samba Member
Joined: October 08, 2007 Posts: 1276 Location: St. Louis Missouri
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kerian159 Samba Member
Joined: February 24, 2008 Posts: 344 Location: Pensacola, FL
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Posted: Tue Jul 25, 2017 6:24 am Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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Yikes that's expensive _________________ 1976 Type II Westy P22
"Growing older, but not up!" |
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mmewing Samba Member
Joined: May 19, 2019 Posts: 1 Location: CA
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Posted: Tue Jun 04, 2019 5:29 pm Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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I know this is a pretty old post but during my research for CHT sensors I found this cool video which might be helpful for someone looking into that topic again.
https://www.youtube.com/watch?v=h8KtvvskT6o |
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Terminatez Samba Member
Joined: June 07, 2015 Posts: 340 Location: Sun Valley, CA
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Posted: Tue Apr 14, 2020 12:32 am Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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I'm currently doing this. So far I've only been doing the programming part of this and using two regular K-type TC. I just ordered some K-type TCs from eBay that have the proper size ring to fit with the spark plugs.
Next part is going to be getting a dual channel vdo sender to be read.
Arduino can't read resistance of the sender so I'll be making a voltage divider circuit and connect it to the Arduino analog pin. I'm also doing some research on a good vdo sender for the type 4 so I can start testing that.
When I've made enough progress I'll be uploading the code to a github repo. _________________ 1972 Westfalia P30 hardtop Campmobile [On-going Restoration]
aeromech wrote: |
I don't think I've ever seen an engine in worse shape. |
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RWK Samba Member
Joined: June 24, 2009 Posts: 1348 Location: S.W. MI
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mikedjames Samba Member
Joined: July 02, 2012 Posts: 2736 Location: Hamble, Hampshire, UK
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Posted: Tue Apr 14, 2020 9:30 am Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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Terminatez wrote: |
I'm currently doing this. So far I've only been doing the programming part of this and using two regular K-type TC. I just ordered some K-type TCs from eBay that have the proper size ring to fit with the spark plugs.
Next part is going to be getting a dual channel vdo sender to be read.
Arduino can't read resistance of the sender so I'll be making a voltage divider circuit and connect it to the Arduino analog pin. I'm also doing some research on a good vdo sender for the type 4 so I can start testing that.
When I've made enough progress I'll be uploading the code to a github repo. |
I did some calculations and worked out that while an Arduino or other controller cannot read resistance, if you power the sender from 3.3 volts via a 110 ohm resistor you can measure the voltage on an ADC channel on the micro - a 100 ohm sender reads a bit under 1.64 volts, a short reads 0...
At the moment my oil pressure system uses a stock VW switch for the warning light and a 0..100 PSI 0.5 volt to 4.5 volt transducer for oil pressure mounted on the end of an extender screwed in the pressure sender hole..
Yes , the EMPI distributor clamp is not flat .
I am slowly working on a replacement for a stock hotwire fuel gauge using an STM F0 ARM microcontroller and a GM instrument stepper motor. Because I like ST more than Atmel.. _________________ Ancient vehicles and vessels
1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.
1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy |
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Terminatez Samba Member
Joined: June 07, 2015 Posts: 340 Location: Sun Valley, CA
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Posted: Sun May 03, 2020 7:46 pm Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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I purchased some k-type thermocouples that have a ring size of 14mm and are bent in an L shape.
Here are some pictures. Don't mind the messy wiring, I had unplugged some jump wires from the old regular style thermocouples I was testing on and the oled display. There are two thermocouples connected to the Arduino through an amplifier. You can see the readings in the serial monitor as Thermocouple 0 and 1.
I have not testing on the engine yet, just a torch.
_________________ 1972 Westfalia P30 hardtop Campmobile [On-going Restoration]
aeromech wrote: |
I don't think I've ever seen an engine in worse shape. |
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Heathintexas Samba Member
Joined: September 24, 2011 Posts: 135 Location: Berlin Germany
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a-marshal Samba Member
Joined: March 21, 2009 Posts: 270 Location: Toronto
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Posted: Thu May 14, 2020 6:36 pm Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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Terminatez
I like the thermocouple wire and 14mm ring...I tried a bunch of different options none of which were as good as the ones I ended up making from copper sheet, can you post the link to where those came from?
Mine has worked well enough for over a year, I didn't have to isolate it but I did burn out my first arduino by wiring it directly to the battery. As it was explained to me the arduino isn't capable of (reliably) shedding the amount of heat generated by taking 12+ Volts and converting in down to the 5 Volts it uses.
On the second pass I put a constant voltage power supply between the battery and the arduino, Something like the one bellow, which I suppose did isolate it since I think that does the same job as the part heathintexas recommended
https://www.ebay.com/itm/283550924132?epid=501587935&hash=item4204f3bd64:g:QcQAAOSwPsZdLvAr
the big heat-sinks were the key..
are you using digital or analog thermocouple amps? _________________ -Ob. vehicle info....
1973 Westy w/ '74 1.8 liter / PDSI (type3?) carbs / 009 distributor / pertronix |
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kerian159 Samba Member
Joined: February 24, 2008 Posts: 344 Location: Pensacola, FL
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Posted: Mon Jun 22, 2020 8:21 pm Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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Terminatez, please post where you got those thermocouples they look perfect for our projects!! I myself got sidetracked for umm well just short of 3 years ( ) but I'm back in the groove of things and brushed off this project. If possible list all of your parts (if you care to share) it is looking amazing! _________________ 1976 Type II Westy P22
"Growing older, but not up!" |
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kangaboy Samba Member
Joined: August 28, 2010 Posts: 1063 Location: St. Louis, Mo
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Posted: Tue Jun 23, 2020 7:23 am Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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kerian159 wrote: |
Terminatez, please post where you got those thermocouples they look perfect for our projects!! |
I second this request. _________________ -74 Standard - "CaliBug" 2084T, MS3X w/FI and Crank Fire
-76 Westy - "Gandalf"
-18 GTI SE
skills@eurocarsplus wrote: |
that fucking thing looks like it drove through a J.C. Whitney catalogue and hit everything on the way out |
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kerian159 Samba Member
Joined: February 24, 2008 Posts: 344 Location: Pensacola, FL
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Posted: Tue Jun 23, 2020 7:54 am Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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From the research I've been doing i'm looking at this as a setup:
Arduino Uno running a sketch with 4 of these https://www.adafruit.com/product/1778 connected to the analog pins (1-4) and then those are connected to https://www.amazon.com/Temperature-Sensors-Thermoc...4YMWMS59EM to pull the temp from the heads. As for a display I haven't figured that out yet either to run a Bluetooth link to an old phone or just get a screen and output it on there, i'm more of a hardware guy than a software so the programming is going to be fun _________________ 1976 Type II Westy P22
"Growing older, but not up!" |
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telford dorr Samba Member
Joined: March 11, 2009 Posts: 3551 Location: San Diego (Encinitas)
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Posted: Tue Jun 23, 2020 12:26 pm Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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I'd be looking for either (1) fully isolated thermocouples, or (2) isolated thermocouple amps. Issue: if multiple non-isolated thermocouples are grounded to the cylinder heads, the head ground forms another thermocouple, and the thermocouples will interact with each other. Differential input thermocouple amps with a large common mode voltage capability and a high impedance to ground could also solve the problem. _________________ '71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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kerian159 Samba Member
Joined: February 24, 2008 Posts: 344 Location: Pensacola, FL
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Posted: Tue Jun 23, 2020 12:30 pm Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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telford, hmm I had read that using thermocouples people were having some issues with grounding but I haven't gotten that far yet. Could you provide links to such creatures?
edit: Something like this?
https://www.amazon.com/DTC-Thermocouple-Temperature-Cylinder-Connector/dp/B00V1XXU52 _________________ 1976 Type II Westy P22
"Growing older, but not up!" |
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telford dorr Samba Member
Joined: March 11, 2009 Posts: 3551 Location: San Diego (Encinitas)
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Posted: Wed Jun 24, 2020 9:40 am Post subject: Re: Arduino CHT, Oil temp, Oil Pressure |
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No, I haven't researched it (I don't have temp sensors on my engine), so no links.
I do know that with most inexpensive thermocouples, the junction is "grounded" to the "case" (in this case, the 14mm ring terminal). It's much cheaper to make this way. An isolated thermocouple has to have some kind of heat conducting insulation between the junction and the case. Unfortunately, this costs more, and leads to a slower temperature change response (not a big deal in this instance). Bottom line: if the thermocouple specs don't specifically say "isolated", I would assume that it isn't.
The display (or signal conditioner) used with a non-isolated thermocouple MUST be isolated from ground, otherwise ground loop current will lead to bogus readings. Remember, thermocouple outputs are measured in millivolts, so it doesn't take much to influence it. _________________ '71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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