Arduino EGT gauge

[Bruce Tuncks]

Has anyone made one? In theory you should just need the Arduino main unit ($12) and a display ($6) and a set of 4 senders ($240 with clamps ) and a few more dollars worth of resistors etc.

 

In practice I suspect things would not be so easy. Calibration for example seems like a problem, and maybe the stability and accuracy of the Arduino may need more work.

 

While I admit to being a cheapskate, it's not only because of the money that I want to make my own thing. I aim to get more fun and bragging rights this way, so long as it can be made to work.

 

 

[cherk]

Has anyone made one? In theory you should just need the Arduino main unit ($12) and a display ($6) and a set of 4 senders ($240 with clamps ) and a few more dollars worth of resistors etc.

Bruce, I've had a play , some time ago with this and it seems feasable. Mine was only 2 channels and I did play with a MUX for the thermocouple amps , but I had other things to get on with, so only ever got to the point of proving (satisfactorily the principles ) rather than hard prototyping.

 

There are many options re thermocouples which are a lot cheaper and the thermo. amps include cold junction references making it pretty straight forward. I'm in a bit of a spin at the moment (time wise) but I see if I can drag out what I have to refresh the grey matter.

 

 

 

[Kyle Communications]

You like doing the home made stuff Bruce dont you

 

I nice Oled display would be better than a std LCD too. You can do all that with the arduino. Look at this new turbine controller for model jet turbines. It has EGT of course

 

 

 

[cherk]

I nice Oled display would be better than a std LCD too.

Hey Kyle, nice OLED, whos' is that.?......I been using the Freetronic one ....that one looks better size wise.

 

 

[Kyle Communications]

I dont know what Oled Gaspar uses but it is a nice one. We use a Newhaven display at work just a std lcd but they are great quality. I found where they actually get manufactured and we buy thousands direct from there. I will ask them if they also do the Oled for Newhaven. and see if I can get some across as we will be getting some spares for our local work. Just checked..looks like they do not do Oled but I will ask the question anyway

 

http://www.newhavendisplay.com/oled-c-119.html

 

http://www.newhavendisplay.com/oled-color-oleds-c-119_626.html?zenid=r3gip9ktlm4dg72nnr0epaatk7

 

 

[Bruce Tuncks]

Nice stuff Kyle, you sure are good at electronics. You were right about the LiFePO4 battery charging . Thanks for the help.

 

Cherk, are you at Farrell Flat in South Australia? I often fly over there, most recently last Sunday in the Libelle. Maybe we could meet up one day.

 

 

[JimG]

Just so you know, the proprietor of Kyle Communications ( very good friend of mine ) , name is Mark Kyle .

 

He doesn't get offended at all by this mistake , I just thought I'd let everyone know......and he sure is good at electronics !

 

Cheers to all

 

Jim G

 

 

[cherk]

Just so you know, the proprietor of Kyle Communications ( very good friend of mine ) , name is Mark Kyle .Jim G

OoohK, thanks Jim.

 

Cherk, are you at Farrell Flat in South Australia?

Yes that's the one Bruce , flying out of Clare Valley now that YFFl is resumed to the woolly jumpers and cropping.

 

Catch up some time in the new year .

 

 

[cherk]

I dont know what Oled Gaspar uses but it is a nice one.

OK thanks Mark, just wondered if there was any ID on the board. The 4D ones look good too ......bit on the pricey side though.

 

 

[sain]

I made an avr based cht gauge a while back, never actually put it in an aircraft though. I've lost the schematic of the final version, sorry.

 

Use a decent regulated power supply, a precision voltage reference for your AREF and a proper instrumentation amp (ideally a temperature compensated thermocouple amplifier) and you can get some pretty good accuracy. EMI can be a problem in an auto/aircraft install.

 

If you want to experiment check out ebay etc. An arduino Nano will cost you about $3 or so.

 

 

[Kyle Communications]

http://thorp18.com/thorpforum/viewtopic.php?f=29&t=7831

 

This guy has posted some code for it

 

 

[Kyle Communications]

http://www.ebay.com/itm/EGT-K-Thermocouple-Amplifier-K-Type-0-1250-C-analog-output-0-5V-AD8495-Arduino-/301739380517

 

You can use this easily

 

 

[billwoodmason]

No doubt we are all looking for a more wallet friendly way to monitor temps with the ability to store info so maybe this discussion will give rise to some innovative solutions for us all. Come on all you techy guys get thinking.

 

 

[Bruce Tuncks]

Thanks Mark for the link. Right now I have got a display working showing T1 T2 T3 and T4 with numeric variables instead of the thermocouple readings. All I did was copy a "hello world" example on the arduino website and vary it a bit.

 

So far it has been easy and cheap ( less than $20) and the expensive bit is coming from Jabiru in the form of the senders and clamps. ($240)

 

Now I have to work out how to connect the thermocouple wires to the arduino so that they read out in degrees.

 

 

[Kyle Communications]

Well you will be reading the analog inputs of the Arduino you will need a opamp to amplify the probes then of course the opamps will put out the corresponding voltage and the arduino just reads it off at the bitrate you set. Quite easy to do there are plenty of sketches on how to do it. The link I sent to the forum you can download the guys code I had a quick look it seems to be ok

 

 

[Kyle Communications]

https://github.com/engineertype/MAX31855

 

http://www.ebay.com/itm/301200852126?_trksid=p2060778.m2749.l2649&ssPageName=STRK:MEBIDX:IT

 

This should do it for you. The Github has the code in C but is easily converted to Arduino which is basically C anyway with a few changes. Schematics are there as well and the 4 way breakout board is there

 

 

[Bruce Tuncks]

[Bruce Tuncks]

Thanks again Mark. The photo shows my crude programming. The numbers are variables which could just be re-named to suit the thermocouple output. The numbers are changing but not in the photo.

 

Not really programming, I just changed things in an example program. My knowledge of C++ is close to zero.

 

I'll order that 4 channel thermocouple processor today.

 

 

[Kyle Communications]

Do a ebay search you may be able to get that interface cheaper than the one I posted

 

 

[Bruce Tuncks]

The 31855 quad breakout arrived today and now I just have to connect it to the Arduino along with the LCD display.

 

A problem for a beginner like me it that the instructions I have are for a single channel 31855 and not a quad, and to my horror the pinouts have different designations.

 

For example, mine has a SCK pin and the instructions have one with a CLK pin. Well nothings easy huh.

 

I'm going to go ahead regardless.

 

 

[Kyle Communications]

Bruce send me the code and documentation for the single version you have and I will have a look at it for you.

 

[email protected]

 

 

[Bruce Tuncks]

Yes an Arduino EGT can be made to work. Here's my example. It's about 25% of the equivalent commercial gear cost, and the money is mainly in the sender units which I bought from Jabiru for about $60 each.

 

BUT my example only works on one channel, and I need a rotary switch to move from one cylinder to another. It works fine on the bench. I am only using one channel of the 4 channel sender in this setup.

 

With a 4 channel sender you would think it easy to have a simultaneous display of the 4 temperatures.

 

Well I think it's possible but the programming is beyond what I can even aspire to. And yes I have looked at learning Arduino C++ or whatever its called. It's too hard and I am too old. Not as hard as Chinese, but up there.

 

I reckon the switched EGT readings will be ok for checking the differences between the 4 cylinders, but what would be good is a CHT gauge where the 4 cylinders are displayed simultaneously and a warning system ( like a flashing display) built in.

 

You would not miss an event of over-high CHT with a system like this. Thanks to Mark Kyle, I'm going to have an expert look at how to do this 4 channel thermocouple sender into an lcd display, if it is possible.

 

Stay tuned.

 

 

 

[cherk]

Yes an Arduino EGT can be made to work. Here's my example. It's about 25% of the equivalent commercial gear cost, and the money is mainly in the sender units which I bought from Jabiru for about $60 each.BUT my example only works on one channel, and I need a rotary switch to move from one cylinder to another. It works fine on the bench. I am only using one channel of the 4 channel sender in this setup.

With a 4 channel sender you would think it easy to have a simultaneous display of the 4 temperatures.

 

Well I think it's possible but the programming is beyond what I can even aspire to. And yes I have looked at learning Arduino C++ or whatever its called. It's too hard and I am too old.

 

Stay tuned.

Bruce ........if you send me via PM a copy of your 'ino sketch' ill have a look thru it....if you wish. I'm not an expert but it should be straight forword enough !

 

 

[Jabiru7252]

Okay, we have an Arduino reading four EGT probes via a four channel MAX31855 board. The temperature on each probe is being displayed as expected but when the probes are immersed in a saucepan of hot water, all four readings drop to zero but of any one probe is in the water it reads as expected (proving the water is not shorting out the probe). If the probe cables are touching those probes read zero. So, are YOU familiar with this and how did you fix the problem. I have a few ideas but would like YOURS first.

 

 

[Kyle Communications]

So are you using the serial reader to read each probe?...how are you reading the 31588 board to the arduino?