Hi,

I am working on a project that the goal is to heat a piece of 20cm wire to 100 degrees C as fast as possible (100ms) and the power source being a 12V lead acid battery. The 20cm wire has a resistance of ~1 ohm.
My question is:
- What heating method would be more effective? AC or DC? DC would be like shorting the battery with a MOSFET switch. AC would be like using an inverter. (note: the accompanying electronics should be small size)
- What do you think of a step up converter and shorting the wire with a higher voltage?

Please share your ideas of what would work best and more effective (fastest)...
Thanks

after looking at the data sheet, I noticed that the thermal response is very slow for my application.

is there any other IC package with better thermal response??

Thanks

Sorry, found my own answer

LM35

Hello,

I am looking for a reliable ambient temperature sensor (integrated in an IC) with analog output (0 to 5V) to be read by arduino.
Note: Thermistors are not an option for me.

Thanks

Hi Billo and BoardBurner,

Thank you guys for your responses.
So here is what the system is about.
First you have to know what this is: http://en.wikipedia.org/wiki/Shape-memory_alloy
what I am doing is testing a piece of this material to find a very high cycle behavior like (100,000 cycles)
I am heating the wire electrically using 14 A in less than 100 ms from room temp to 100 degrees C.
right now we have position and force feedback which are used for control. I want to add temperature to the system not as feedback but just raw data to be analyzed later( hence NO processing).
the position and force are working and logging and analyzing fine. My problem is a temperature sensor (non contact).

To answer Billo question about why noncontact? I do not want to take out heat from the wire, no matter how small, because if I take out heat, then it will change the behavior of the wire.

I have consulted this page which has a list of all companies that manufacture IR temp sensors: http://www.directindustry.com/industrial-manufacturer/infrared-temperature-sensor-71767.html
I came across this which has the closest match to what I am looking for: http://www.micro-epsilon.com/temperature-sensors/thermoMETER_CT_basic/thermoMETER_CTfast/index.html
its the same company that Boardburner mentioned.
what I am exactly looking for are these specs:
- fast response (1 ms or less) (under 10ms is OK too)
- measurement of spot size of 0.5 mm
- measurement range of 0 to 200 degrees C
- 0 to 5V analog OR digital output to be read by microcontroller.

Also I think using photomultiplier and kinda making my own sensor would become too costly and not very accurate...

Thank you,

I kinda need the response time to be 1 ms or less.
I have system that changes temperature from room temp to 100 Degrees C in about 100 ms. Then it cools back down to room temp in 3 to 4 seconds. I want to be able to record this change of temperature.
So a response time of 100 ms is kind of useless!

I was searching online about only the response time... Does any company make non contact digital sensors with 1 ms response time???

Thanks

Wow man... you rock!!!

I cant find the datasheet for this thing though... what is the response time of this thing?

I kinda need a off the shelf part.
I would imagine building optics would cost more than that.
Could you give the part for your 'solution'?

Thanks

Thanks for the response Billo,

This is a good part, but I was looking for something that can measure surface temp of a wire o.5 mm diameter. This part is not suitable for this. Also I did not find the response time for it.

Thanks,

Hi,

I looking for a fast response ( 1 ms or less) contactless (laser or IR) Thermometer that can accurately measure surface temperature of a wire (0.5mm diameter).

Does anyone have any ideas as to where to look? What company? etc...

Thanks

Hi Rob,

Thank you for taking the time to recognize this. You are absolutely right!!! thanks a lot for that.

The fact is that this line is blocking everything: myPort.readStringUntil('\n');
The 'if' statement has nothing to do with it. I commented out the if statement and it still was lagging.

Now, how do I process each character and achieve the same result as I am trying to do, but much faster?

Thanks

Thank you guys for the input.

I tested another program to measure the speed of the serial data comming in. Here it is: (it is a modification of the example code on processing website)

Code:

import processing.serial.*;
 
Serial myPort;    // The serial port
PFont myFont;     // The display font
String inString;  // Input string from serial port
int lf = 10;      // ASCII linefeed
 
void setup() {
  size(400,200);
  println(Serial.list());
  myPort = new Serial(this, "COM5", 57600);
  myPort.bufferUntil(lf);
}
 
void draw() {
  background(0);
  text("received: " + inString, 10,50);
}
 
void serialEvent(Serial p) {
  inString = p.readStringUntil('\n');
}

This code displays the data steam as fast as the arduino.
I think the reason that the original code is slow is because of write speed of processing. I am writing the serial data into an array and I think thats why this thing is very slow.
Correct me if I am wrong.
Is there a way to store the data faster into the Data[] array.

Thanks

The code is intellectual property of my company. Thats why...

Let me ask my question another way.
Is there any other way make the comm link between arduino and processing faster (not necessarily serial) ? I need at least 1MB/sec of transfer rate.

Thanks

I can't post the code.
this is the only relevant part that I am having problems with.

Hi Paul,

You can assume the whole processing program is just reading and storing the data into an array (the code). I tried this myself to narrow down where the lag is occurring. The 13 second lag is because of this section.
The Arduino is sending 6 sensor values every 5 ms for 5 seconds and then it stops.

Thanks