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Thermocouple to PC interface, redux

I want to take my Type K thermocouple, interface to some sort of device (call it Black Box A) and have Black Box A interface (by serial port is fine) to a PC, to record temperature data (T between 20 C and 100 C) from an experiment. Even better if it can log data from two thermocouples simultaneously, but for now one is fine.

To the flame throwers out there: my background is in chemical engineering, not electrical engineering.

I'd thought an ATTiny11-6PC ($0.53 from Mouser!) would do the trick. Was planning on using the on-board analog comparator to provide the A/D conversion, as mentioned here:

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And I know I'll need a high-voltage programmer, something like this:

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However, when looking for schematics to cobble this all together (to build the "motherboard", so to speak), I come up blank.

Any suggestions?

Maybe I'm barking up the wrong tree... do I simply need an ADC without a microcontroller to send the data serially to a PC?

Thanks,

Michael

Reply to
mrdarrett
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Wiring up a uP is pretty simple if you've done it once. Is this a temperature measurement project or a uP learning project? If it's temperature measurement, you can buy serial interface or USB analog I/O modules all over the place.

Cheers,

Phil Hobbs

Reply to
Phil Hobbs

Yeah, it's a learning project.

So, am I on the right track with the ATTiny11? Just looking for a schematic... no I don't need an LCD display on the Black Box... a

40-pin AT90S--- just seems like immense overkill for something simple like this...

Michael

Reply to
mrdarrett

What will you use for a cold junction? I'd buy a DMM with a type K input and a serial connection - the price will be a fraction of the time investment.

Reply to
Homer J Simpson

Tiny 11 does not have a UART, which you need to talk to a PC.

Yes, if you plug in a board on the PC. Or you can use a serially connected board with A2D.

Reply to
linnix

Take a controller with ADC such as the Tiny26 and an NTC.

Rene

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Reply to
Rene Tschaggelar

Some ideas here:

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Reply to
Donald

...

What's your budget? If you just want to get the job done, then check this out:

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Or browse their whole website. (just truncate the link.)

I don't work for them, I just remembered "Omega" and checked for one. As it happens, it's rather a pleasant website to visit, as well. :-) (no flash, no java, no geopoops, etc. :-) )

Have Fun! Rich

Reply to
Rich Grise

...

Then, just pull stuff out of your hat and see what works! That's what "learning" means. ;-)

Have Fun! Rich

Reply to
Rich Grise

I just might give that a shot. Thanks. I'd actually bought my non-RS-232 handheld thermocouple display from them for about $100, a decade ago. Came in really handy.

Part of the fun is also in learning something new. Which I did, today... use a MAX232 or equivalent to interface to the serial port... hmm...

Fry's in Sacramento sells a breadboard (with wires) for about $6.25, last time I checked last week. Don't have exact specs, but looking at a ruler, it's probably about 7 or 8 inches by 3 inches, or so. Know anyone who can beat that price? ;-) Else I'll have to drive out there next time I'm in the area (kinda far from East Sac, where I am).

To my surprise, the Fry's does NOT carry any PICs or Atmel chips. Not even any PIC/Atmel books, or even a copy of Circuit Cellar magazine. Shame. But they have plenty of floppy disk controller chips, and even a few Z-80s for sale.

Michael

Reply to
mrdarrett

$100 USB 24 bit multi-channel with enough resolution and low noise to directly digitize the low mV signals from themocouples, LabVIEW and .NET drivers

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Reply to
Steve

Thanks for that.

After some research, I think I'll stick with this one:

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It has a MAX232 for the RS-232, and an LM35 for ambient temperature reference (if I understand the drawing correctly).

I won't need the 44780 LCD, and I probably won't need the 74HCT4052 multiplexer (or is it a necessary part of the design?)

The idea was to use it to monitor a solar cooker ( that I *still* haven't built yet (!!) ) in the backyard. Will probably connect the temperature acquisition device to an old laptop I have lying around.

Thanks,

Michael

Reply to
mrdarrett

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