Re: [time-nuts] Thoughts on IR thermometers?
On Tuesday 27 May 2008 11:31:49 pm Patrick wrote: I tried to use a cheap IR thermometer to do some quick, pre-circuit analysis tests, a couple of years ago on a particular job. It went bad, the laser did not even line up with the area being measured, I missed a burning hot capacitor and wasted a lot of time. http://www.towerhobbies.com/ has several Temp Guns in the $25 to $50 range. I was thinking about buying a better one this time. Does anyone have any suggestions? Melexis MLX90614 is a Digital plugplay Infrared thermometer in a TO-39 can. http://www.melexis.com/ProdMain.aspx?nID=615 The object temperature can range from -70 to +380'C. You can get them from Future's Component Store. http://www.componentsuperstore.com Have two on the bench here, but have not fired them up yet. I had a hell of a time trying to read my Son's temperature last night when he had a fever, anyone tried one of these out on their children? They have a medical grade one, also Automotive grade ones. -- http://www.wearablesmartsensors.com/ http://www.softwaresafety.net/ http://www.designer-iii.com/ http://www.unusualresearch.com/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thoughts on IR thermometers?
I found a cheap IR sensor (not a spot meter) useful to identify the one IC that's warmer than the others in a fully populated PWB. I usually use my fingers for that sort of test. :) Warning. Don't try it on really hot chips! I have a small lump on my thumb leftover from touching a chip that was trying to self-destruct. (bus clash) Does anybody know of a low cost camera that works in IR? I expect somebody probably makes a slightly modified version of one of the USB cameras for just this sort of work. I found this while poking around. How to modify your webcam: http://www.hoagieshouse.com/IR/ Basically, take it apart, remove IR filter, add visible filter (old slide film), put it back together. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] thoughts on IR thermometers??
Hello Patrick, you got already a lot of good comments. I am using since years a IR temp measurement tool from Snap-on, mod. RTEMP2PB, with a resolution of 0.1 deg. showing in deg. C and F. The distance to spot size is 8:1, a more narrow range would be sometimes preferable but for most cases it is ok. I do not want to miss this device anymore. Of course, that device never measures the core temperature of a body/ mass but just the radiation via its surface and they are not not very good on the absolute values (precision). At room temp the measurement value is conform within a few tenth to the real values, but the device seem to not have a tempcoeff. compensation. Outside in winter or at higher temperatures in summer the reading starts to wander up to around 1 or 2 deg. C away. I got with this device a sheet with a list of radiation coefficients for the most practical masses like concrete, dry wood, metals etc. but I do not apply it normally. I use this radiation thermometer for fast and quick look on black radiators of oscillators and other devices quite successful and can easily watch even fast changes. E.g my PRS10 with the standard radiator (a bit too small) does show around 45 deg. C at 22 deg. C room temperature. I am thinking to bring it down by a bigger cooler size and somewhen finally stabilizing the coretemp by a regulated peltier element. It is also wise watching power supplies and other big consumers ;-) and looking for thermal leaks on cold winter days. E.g. I measured the temperature gradient on my (32mm triple glass) windows and found some weak points in the design of the already very thick frames.The fixation of the glass may still to be improved. When measuring I do always look to find the center point of radiation by scanning and observing the max.(or min.) reading. The precise amount is not that important I believe, but one can easily find the hot elements and define the value reproducible. I do countercheck always with the reading from a concrete inner wall which is very stable due to a very good insulated house :-) Unfortunately there is no interface to transfer the readings, but there is a hold for the actual reading and the max. value during the on time. Do you know how one can know without looking if the sky is clear or cloudy? Day or night, a bright sky does show temperatures below -33 deg.C (readout limit) and clouds do reflect the earth (re)radiation and show then -3deg C to +3 deg C, depending the density of the clouds. I never found a practical circuit or schematic for such a meter. It would perhaps be interesting to build such a meter personally. regards Arnold Tibus On Mon, 26 May 2008 20:21:02 -0400, Patrick wrote: Hey Everybody I tried to use a cheap IR thermometer to do some quick, pre-circuit analysis tests, a couple of years ago on a particular job. It went bad, the laser did not even line up with the area being measured, I missed a burning hot capacitor and wasted a lot of time. I was thinking about buying a better one this time. Does anyone have any suggestions? Do you think they are useless for PCB tests? Caps should not be hot and power resistors and transistors should not be cold right? but the spot size to laser ratio on most of these are not good, are they still useful? I had a hell of a time trying to read my Son's temperature last night when he had a fever, anyone tried one of these out on their children? Thanks in advance-Patrick ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thoughts on IR thermometers?
Patrick, After many attempts to get repeatable results from various IR spot thermometers, our design group spent a few $$ with a local independent test lab using their big $$ IR imaging system. The results were amazing prompted us to just bite the bullet get one. They have since dropped in price, but I don't know the current market $. Even if your needs wallet can't justify purchase, you'll be well repaid just to lease/rent or buy time on someone else's. A hard copy thermal map under various operating conditions can be a real life saver for later reliability. Pete Rawson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thoughts on IR thermometers?
Dear Time-Nuts, A not so off the topic question: Does anyone have some documentation on HP 2804a thermometer? It is using a quarz crystal as the probe, and therefore is an object of interest for the true time-nut. Predrag Dukic At 16:25 28.5.2008, you wrote: Patrick, After many attempts to get repeatable results from various IR spot thermometers, our design group spent a few $$ with a local independent test lab using their big $$ IR imaging system. The results were amazing prompted us to just bite the bullet get one. They have since dropped in price, but I don't know the current market $. Even if your needs wallet can't justify purchase, you'll be well repaid just to lease/rent or buy time on someone else's. A hard copy thermal map under various operating conditions can be a real life saver for later reliability. Pete Rawson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Thoughts on IR thermometers?
Hey Everybody I tried to use a cheap IR thermometer to do some quick, pre-circuit analysis tests, a couple of years ago on a particular job. It went bad, the laser did not even line up with the area being measured, I missed a burning hot capacitor and wasted a lot of time. I was thinking about buying a better one this time. Does anyone have any suggestions? Do you think they are useless for PCB tests? Caps should not be hot and power resistors and transistors should not be cold right? but the spot size to laser ratio on most of these are not good, are they still useful? I had a hell of a time trying to read my Son's temperature last night when he had a fever, anyone tried one of these out on their children? Thanks in advance-Patrick ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thoughts on IR thermometers?
Hi Patrick: Many decades ago I used a Barnes Engineering spot IR sensor. It's cost tens of thousands of dollars and had a microscope for alignment. The problem then and now is that you need to know the IR emissivity of the thing you're looking at in order to get temperatures. If you try to read a mirror and are seeing a clear blue sky reflection in the mirror, even though the mirror is at room temperature you will read some large negative temperature like - 60 deg C. A way around that is to coat everything with a black paint that's also black for IR, but that's messy. A simpler way is to get a temperature probe for your DMM and just touch parts. For a crude look use a digital camera that has the IR blocking filter removed and you can see near IR. For example a car driving away viewed in near IR shows red for LED lights and bright white for filament lights. Another problem with low cost IR temperature sensors is that the beam angle is around 90 degrees. Have Fun, Brooke Clarke http://www.prc68.com/P/Prod.html Products I make and sell http://www.prc68.com/Alpha.shtml All my web pages listed based on html name http://www.PRC68.com http://www.precisionclock.com http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Web Cam Patrick wrote: Hey Everybody I tried to use a cheap IR thermometer to do some quick, pre-circuit analysis tests, a couple of years ago on a particular job. It went bad, the laser did not even line up with the area being measured, I missed a burning hot capacitor and wasted a lot of time. I was thinking about buying a better one this time. Does anyone have any suggestions? Do you think they are useless for PCB tests? Caps should not be hot and power resistors and transistors should not be cold right? but the spot size to laser ratio on most of these are not good, are they still useful? I had a hell of a time trying to read my Son's temperature last night when he had a fever, anyone tried one of these out on their children? Thanks in advance-Patrick ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thoughts on IR thermometers?
I got one of the passive detectors from thinkgeek and it does a pretty decent job. I can tell you which corner of a geode system-on-a-chip has the bits that are working hardest, for example. Or when I need to let my brakes cool off after doing laps at the race track. http://www.thinkgeek.com/gadgets/electronic/8024/ CK On Tue, May 27, 2008 at 8:31 PM, Patrick [EMAIL PROTECTED] wrote: Hey Everybody I tried to use a cheap IR thermometer to do some quick, pre-circuit analysis tests, a couple of years ago on a particular job. It went bad, the laser did not even line up with the area being measured, I missed a burning hot capacitor and wasted a lot of time. I was thinking about buying a better one this time. Does anyone have any suggestions? Do you think they are useless for PCB tests? Caps should not be hot and power resistors and transistors should not be cold right? but the spot size to laser ratio on most of these are not good, are they still useful? I had a hell of a time trying to read my Son's temperature last night when he had a fever, anyone tried one of these out on their children? Thanks in advance-Patrick ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- GDB has a 'break' feature; why doesn't it have 'fix' too? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thoughts on IR thermometers?
I found a cheap IR sensor (not a spot meter) useful to identify the one IC that's warmer than the others in a fully populated PWB. That has been useful to isolate the one bad part, but a contact thermometer would have been almost as useful. While the IR sensor reading depends on emissivity, the contact thermometer depends on ... contact. Not easily reproduced. The IR sensor may be off, but readings on a given part are more reproducible, in my experience. Another useful application for an IR sensor is to spot the area in the ceiling where you need more insulation. I found out that way that squirrels had a party in my attic and moved the insulation on one side of the house... I also used it to verify that the reflective film applied against the window reduced the temperature of the sun shades by a couple of degrees F in the summer. That would have been much harder to do with a contact thermometer (sun shades are thin plastic, with little thermal mass and even less conductivity). So, in my experience, an IR sensor is useful around the house, more so than around the shack. I agree that absolute temperature measurements are in most cases out of the question because of the unknown emissivity and the broad pattern, but for relative measurements, they have their use. Didier KO4BB -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brooke Clarke Sent: Tuesday, May 27, 2008 10:46 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Thoughts on IR thermometers? Hi Patrick: Many decades ago I used a Barnes Engineering spot IR sensor. It's cost tens of thousands of dollars and had a microscope for alignment. The problem then and now is that you need to know the IR emissivity of the thing you're looking at in order to get temperatures. If you try to read a mirror and are seeing a clear blue sky reflection in the mirror, even though the mirror is at room temperature you will read some large negative temperature like - 60 deg C. A way around that is to coat everything with a black paint that's also black for IR, but that's messy. A simpler way is to get a temperature probe for your DMM and just touch parts. For a crude look use a digital camera that has the IR blocking filter removed and you can see near IR. For example a car driving away viewed in near IR shows red for LED lights and bright white for filament lights. Another problem with low cost IR temperature sensors is that the beam angle is around 90 degrees. Have Fun, Brooke Clarke http://www.prc68.com/P/Prod.html Products I make and sell http://www.prc68.com/Alpha.shtml All my web pages listed based on html name http://www.PRC68.com http://www.precisionclock.com http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Web Cam Patrick wrote: Hey Everybody I tried to use a cheap IR thermometer to do some quick, pre-circuit analysis tests, a couple of years ago on a particular job. It went bad, the laser did not even line up with the area being measured, I missed a burning hot capacitor and wasted a lot of time. I was thinking about buying a better one this time. Does anyone have any suggestions? Do you think they are useless for PCB tests? Caps should not be hot and power resistors and transistors should not be cold right? but the spot size to laser ratio on most of these are not good, are they still useful? I had a hell of a time trying to read my Son's temperature last night when he had a fever, anyone tried one of these out on their children? Thanks in advance-Patrick ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. Internal Virus Database is out-of-date. Checked by AVG. Version: 7.5.519 / Virus Database: 269.23.11/1422 - Release Date: 5/8/2008 5:24 PM Internal Virus Database is out-of-date. Checked by AVG. Version: 7.5.519 / Virus Database: 269.23.11/1422 - Release Date: 5/8/2008 5:24 PM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thoughts on IR thermometers?
On Tue, 27 May 2008 23:31:49 -0400, Patrick [EMAIL PROTECTED] wrote: Hey Everybody I tried to use a cheap IR thermometer to do some quick, pre-circuit analysis tests, a couple of years ago on a particular job. It went bad, the laser did not even line up with the area being measured, I missed a burning hot capacitor and wasted a lot of time. Since the response profile of those cheap lens-less thermometers is a broad cone, the laser is at best a joke and at worst an outright fraud. I was thinking about buying a better one this time. Does anyone have any suggestions? Do you think they are useless for PCB tests? Caps should not be hot and power resistors and transistors should not be cold right? but the spot size to laser ratio on most of these are not good, are they still useful? You might want to take a look at Wahl's (recently gobbled up by palmer instruments) line of instruments. They're a very old name in the business. I've been using their stuff since the 70s. They used to and probably still do make a unit especially for inspecting PCB components. It has a tiny focal spot. http://www.palmerwahl.com/heat-spy-hand-held-infrared-thermometers.php I have an older DHS-24 series and a fairly new DHS-215 series private labeled for Omega Engineering. Example: http://www.omega.com/ppt/pptsc.asp?ref=OS532E_OS533E_OS534ENav=temj04 The major feature of the Omega version is their patented circular laser pattern that fairly sharply defines the sensitive area at any distance. I've tested my unit with a heated up power resistor. The laser quite accurately delineates the sensitive area. Mine also has a Type T thermocouple input which is very handy because I can apply the thermocouple to an object of similar emissivity to what I'm going to inspect and then adjust the emissivity control to make the infrared part read the same as the thermocouple. That removes all guesswork with emissivity coefficients. Mine is the 50:1 cone size. With that fairly sharp cone I can, for instance, stand back at a reasonable distance and survey an air conditioner condenser to figure out where the liquid line is. IR thermometers that actually work aren't cheap but then few things are. I'm well pleased with the value I received in my unit. John -- John De Armond See my website for my current email address http://www.neon-john.com http://www.johndearmond.com -- best little blog on the net! Tellico Plains, Occupied TN So you're a feminist... Isn't that cute! ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] thoughts on IR thermometers??
Just on the subject of body temperature, the IR thermometers are quite good for skin temperature as the emmissivity of people is high, BUT, skin temperature is about 31 C, and is not core temperature, Hence the need to stick thermometers under tongue or elswhere where it is close to core. There are IR themometers that look at ear drums, they give good core temperature readings. I use a RAYTEK cheap IR thermometer, it works very well if you make allowance for emmissivity. My HP10811 oscillator has such a low emmissivity that the thermometer cant detect any heat from the oven. It does show up small variations in ceiling temperature and other small variations. cheers, Neville Michie On 27/05/2008, at 10:21 AM, Patrick wrote: Hey Everybody I tried to use a cheap IR thermometer to do some quick, pre-circuit analysis tests, a couple of years ago on a particular job. It went bad, the laser did not even line up with the area being measured, I missed a burning hot capacitor and wasted a lot of time. I was thinking about buying a better one this time. Does anyone have any suggestions? Do you think they are useless for PCB tests? Caps should not be hot and power resistors and transistors should not be cold right? but the spot size to laser ratio on most of these are not good, are they still useful? I had a hell of a time trying to read my Son's temperature last night when he had a fever, anyone tried one of these out on their children? Thanks in advance-Patrick ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
