arduino egt

[65fpvmustang]

Thinking about getting one for the falcon to read egt.
http://www.ebay.com/itm/Octo-8-MAX31855-thermocouple-breakout-board-for-5V-systems-type-K-K-type-/251802776832?_trksid=p2141725.m3641.l6368

[65fpvmustang]

This is my other option $300 kinda pricey.
http://www.diyautotune.com/catalog/canegt-channel-thermocouple-interface-p-542.html

[Rx7man]

Price is good on the first one, but with the Octo  board they say it takes 1/8th of a second to get a reading because of multiplexing, while the single, dual, and quad boards  are non-multiplexed, and can be read MUCH faster.. I would go with a dual.

Another option, I haven't priced it, but it might be less than $300, is this
Hewitt Industries (Pyrometers)
Look under "control modules" --> Exhaust temp and that looks like it would do the trick as well, and it's well encased.

I may have to pick up one of those dual pyro modules.. it's something I definitely lack input from on the Arduino, and since it goes over SPI it doesn't take up any analog inputs.. kinda nice.

[Rx7man]

Just so *I* can find it again when I want it, heres a link to the dual... The quad has a different (better) chips, but from what I could tell it didn't offer any features I found important.. it has some de-jittering, etc, but I can do all that myself. 

Dual MAX31855 Thermocouple Breakout Board for 5V Systems Type K K Type | eBay

I'm actually considering using a pyro probe for compressor outlet temperature rather than the standard NTC thermistors used in most gauges and sensors (GM, ford, autometer).  Besides freeing up analog inputs by going over SPI, they are more accurate too.

[65fpvmustang]

I saw the read speed was slow but reading all 8 in 1 sec. I figured was quick enough. I could just drop to the Quad board and read at the 4 y pipes. then if i get a odd reading it's  1 out of 2 cylinders. Plus the Y pipes are more hidden and mostly straight.

http://www.ebay.com/itm/EGT-K-Type-Thermocouple-Temperature-Sensors-with-Clamp-Bendable-Probe-Special-/252242806269?hash=item3abad7c5fd:g:yy8AAOSwFqJWj-sN

[65fpvmustang]

really like bouncing ideas off you guys.
The after cooler has it's own radiator in the cowl.
The plan is to run it for a bit then change the cam to match one in dyno chart. my build is almost identical to.
The dyno chart is NA turbo build. Goals are 800hp at 6k and 400hp at 3k.
current cam is big 8inhg at idle.But makes closer to 500hpNA at 6k

[Rx7man]

The problem with a slow read speed is you're going to have to do something while waiting for it, which adds a lot of code complexity.   with the quads (even dual quads), you can dedicate an arduino port for the SPI cable select pins, and it makes it easier to access each one.  Each bit of a port corresponds to a pyro probe, and you don't have to check to make sure you disable one of them before enabling the next one.. and direct port access is a little faster than using the "digitalRead" and "digitalWrite" functions of arduino.

It would go something like this

Code Select Expand


#define PyroPort PORTC //whatever the address of the port you're using is

int PyroTemps[8]; //an array of integers to hold the pyro temps.. it's easier as an array than individual variables

void setup(){
SPI.begin();
}
void loop(){
ReadPyros();
}

void ReadPyros(){
  for (int bitnum =0; bitnum<=7; bitnum++){
  int bitaddress = 1<<bitnum; //set the corresponding bit to 1 by bitshifting
  PyroPort = bitaddress;  //write to the port
  //may need to wait a few micros here
  PyroTemps[bitnum] = SPI.read(); //may be a little more complex than this.. you get the jist of it
  }
}


[65fpvmustang]

leaning towards this one now lol
http://www.ebay.com/itm/Quad-MAX31856-thermocouple-breakout-board-for-5V-systems-MAX31855-upgrade/252040638597?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D35006%26meid%3D0548ed71ea7e4bbfa8bd02aa5d6a39a7%26pid%3D100005%26rk%3D3%26rkt%3D6%26sd%3D301214589468

[Rx7man]

I'm sure it would do nicely.. just a note though, it comes with ONE probe, the others come with 2... but since the probes aren't really designed for EGT measurement, I guess you might have to get different ones anyhow (like you pictured). 

I would be more prepared to go for the quad if it was a little cheaper (old style chip) and had 4 probes with it... I may break down and get it anyhow... Pre turbine, ambient, post turbine, and post intercooler.. that would give me a pretty darned good idea of how everything is performing.  I have a couple extra pyro probes anyhow so I could make it work with what I have.

[65fpvmustang]

yeah i like the clamp on egt probes. I have 1 extra 4' J and k thermocouples. If you want them.

[Rx7man]

I'll have to see how the project comes along, thanks for the offer.  I like the bung style probes.. like the clamp on style but threaded

[65fpvmustang]

older quad board there is a big price jump.
http://www.ebay.com/itm/301200852126?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[Rx7man]

That is quite a jump. I should look on Mouser and see the actual price difference of the chip.. probably 1 or 2 bucks x 4 pieces

[65fpvmustang]

prices were very close on mouser.
Ordered these clamp on style $9 shipped. I'll order one of the quad boards after pay day.
http://www.ebay.com/itm/252247093073?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[Rx7man]

Cool

I guess the guy has to pay for the development of the new board, etc.   Still dirt cheap when you look at the prices of any finished products!