Hello Fellows
I am very new to this and I hope I am posting in the correct place.
I am asking for a suggestion. I need to read 10 analogue signal of 0 - 5 volts. I need to record for a max time of 45 seconds and then dump these readings into something like excel so I can graph. My weak point in electronics is doing "stuff" like this. A good friend try Arduino, so here I am. Would ane one take the time to steer me in a direction.
racear
You can use gobetwino to save all te results to an excel document. This would need you to use the Serial.print() command, and some characters before that, that gobetwino understands. Reading 10 analog values should be possible with an analog multiplexer, although I have never used them, so you'll need to find out how to.
Onions.
More details are needed.
Do you need to read all 10 at the same time for 45 seconds?
Do you need to read at a time, 45 seconds worth of each?
What sampling rate do you need to read them them at?
Also saying how much precision you need is important.
For example, the Arduino Uno has 10-bit ADC, which means you can read with a best precision of 5 millivolts (ideal scenario).
For most higher-precision applications, you will need to connect an external ADC.
I am going to use this on a Dynomometer to read O2 sensor readings. A run on a dyno will last about 20 seconds. At present I am reading 8 EGT but I want to go to 10 O2 sensors with 0 to 5 volt output. At present I read at .05 volt but I honestly dont know how precise I need the reading. Trying to understand that now. The EGT reading is 4 times per second per channel so I guess that is a good place to start. If this doesnt answer your question, please ask.
reed
Might be easier and cost effective to buy a ready to go data aquisiton unit like below. I think in the past these starter units sampled at something like 240 samples/sec. Decent price.
Here is the response time of a typical O2 sensor as found at http://www.picoauto.com/applications/lambda-sensor.html .
Most lambda sensors will cycle from rich to lean in about 50 to 100 milliseconds, and from lean to rich in 75 to 150 milliseconds. This is referred to as the “transition time”. If the O2 sensor is taking significantly longer to reverse readings, this too is an indication that it is getting sluggish and may need to be replaced.
Using this information, you could ball park that readings on each sensor should be made around every 75 to 100 milliseconds. I didn't find the response time of an EGT but, it is metal and must have some time delay to change output.
Mark
Well one thing is for sure, you fully understand what I want to do. You are totally correct about how a Lamda sensor works and how to check if one is going bad. Sluggish change says get it out. So you understand that I want to record every cylinder. At the present I am using EGT which is a indicator but can be fooled. O2 sensing is the cats meow for tuning, so I do need to read all eight cylinders and record. Doesnt have to be real time but I do need to record so that i can go back and correct that cylinder
racear
$29! Three of them for 12 channels. And PC software to go with it. That is a deal.