Hi all, although I can only contribute questions and not too many answers, here’s what’s on my mind: 1. Wouldn’t both solutions (IR thermometer and thermocouple on surface) measure the flame temperature rather than the surface temperature of the material? After all, the flame also emits IR (depending on the gas being used.) Regardless of the temperature at which ablation starts, I suppose the thermocouples must be able to withstand the flame temperature. 2. Do I understand correctly, that in order to determine the emissivity of the surface you’d need a “calibration run” with IR and thermocouples? Is emissivity temperature dependent? Hopefully not, so I suppose the calibration could be done at a lower (non-destructive) temperature!? 3. Partially answering my previous question: When the material gets very hot and charred, it will probably change its emissivity. Some of the materials are nearly white, but will probably turn black when the binder undergoes pyrolysis. I’d guess it’s very likely that this also changes IR emissivity!? 4. For “normal” materials (non-transparent), what’s the typical range of emissivity? How much error would it introduce into the temperature measurement to just assume a reasonable fixed value? 5. Pt-100 sensors had also come to my mind, but I’d assume they require more complex analog circuitry to interface them to a computer and get accurate results. Am I right? It almost seems that the method for measurement of surface temperature is a valid research topic in its own right ;-) Have a good day! Mattias From: sugarshot-bounce@xxxxxxxxxxxxx [mailto:sugarshot-bounce@xxxxxxxxxxxxx] On Behalf Of Hans Olaf Toft Sent: Wednesday, November 26, 2014 4:00 AM To: sugarshot@xxxxxxxxxxxxx Subject: [SS2S-Main] Re: Tempilstick Ablation is likely to happen in the 400-600 C range, but the unit should be able to measure higher temperatures just in case. Getting the emissivity right may require a few experiments (and thermocouples). Warning: the cheap IR thermometers may have a fixed emissivity setting. Hans On 11/25/2014 08:34 PM, Brian Su (Redacted sender cycloniterulez@xxxxxxxxx<mailto:cycloniterulez@xxxxxxxxx> for DMARC) wrote: From my very limited experience with IR thermometers, they're only accurate when correctly compensated for the emissivity of the surface being measured. On top of that, the cheap units can't measure above 900 degrees Celsius. Kind Regards, Brian Su. Sent from my iPhone. On 25 Nov 2014, at 18:26, Vicente Alvero Zambrano <vicente_alvero_14@xxxxxxxxxxx<mailto:vicente_alvero_14@xxxxxxxxxxx>> wrote: Exactly. We need a continuously record the temperature. Therefore, the two proposed options, the pencil and the thermocouple are not suitable for our purpose. We will use several thermocouples within the cone, temperature recording. But abroad, will be in direct contact with the flame. That is why, we want to use an infrared thermometer. Does anyone know how we can do one and connect it to the computer? _____ Date: Tue, 25 Nov 2014 18:32:57 +0100 From: hot@xxxxxxxxxxxxx<mailto:hot@xxxxxxxxxxxxx> To: sugarshot@xxxxxxxxxxxxx<mailto:sugarshot@xxxxxxxxxxxxx> Subject: [SS2S-Main] Re: Tempilstick Thermocouples are cheap and work well, but if they are embedded in a sample that gets torched, they will at best record the surface temperature of the sample at the brief moment they are at the surface. It may work - and even provide usefull data - but an IR thermometer will read the surface temperature continuously. Hans On 11/25/2014 05:34 PM, Brian Su (Redacted sender cycloniterulez@xxxxxxxxx<mailto:cycloniterulez@xxxxxxxxx> for DMARC) wrote: This one sure looks much better. Kind Regards, Brian Su. Sent from my iPhone. On 25 Nov 2014, at 16:27, Grant Saviers <grants2@xxxxxxxxxxx<mailto:grants2@xxxxxxxxxxx>> wrote: Here is another ebay seller with all thermocouple options, packaging variations, temperature compensated junctions, and EMI filtering, etc. Looks to be professional grade engineering: http://www.ebay.com/itm/Quad-Channel-K-Type-Thermocouple-Amplifier-Conditioner-Analog-Output-AD8495-/331032888967?pt=LH_DefaultDomain_0&hash=item4d13190687 On 11/25/2014 8:10 AM, Grant Saviers wrote: A type K thermocouple is good to 1250 C. It will need a simple instrumentation amplifier to get the signal voltage to a range compatible with the Arduino A/D converter. For about $10 in parts you can build your own IN-AMP. There are several choices for single chip IN-AMPs that will do the job and here is a board from China for $10, and the chip output is 10mv/deg C. http://www.ebay.com/itm/AD597-Ultimaker-Temperature-Control-Board-K-Thermocouple-Signal-Amplifier-/321597894984?pt=LH_DefaultDomain_0&hash=item4ae0ba7148 Grant On 11/25/2014 1:12 AM, flint hapirat (Redacted sender flinthapirat@xxxxxxxxx<mailto:flinthapirat@xxxxxxxxx> for DMARC) wrote: One comment - The tempilstick temperature pens are rated between 38c-1093c... Hope this is still helpful. _____ From: Vicente Alvero Zambrano <vicente_alvero_14@xxxxxxxxxxx><mailto:vicente_alvero_14@xxxxxxxxxxx> To: "sugarshot@xxxxxxxxxxxxx"<mailto:sugarshot@xxxxxxxxxxxxx> <sugarshot@xxxxxxxxxxxxx><mailto:sugarshot@xxxxxxxxxxxxx> Sent: Sunday, November 16, 2014 9:10 PM Subject: [SS2S-Main] Re: volunteering Thanks for your reply Markus, It is a good idea. The main problem I see is that we need to measure high temperatures. I do not know exactly how much, but around 1200ºC. And this only measures halfway. Do you know if there is a sensor for arduino with this possibility? _____ From: m.bindhammer@xxxxxxxxxxx<mailto:m.bindhammer@xxxxxxxxxxx> To: sugarshot@xxxxxxxxxxxxx<mailto:sugarshot@xxxxxxxxxxxxx> Subject: [SS2S-Main] Re: volunteering Date: Sun, 16 Nov 2014 23:21:22 +0800 Hi Vicente, It is quite easy to build a data logger with an Arduino based micro controller, SD card, SD card socket, HEF 4050 voltage level shifter, DS1307 RTC and one (or more) MLX90614 IR thermometer(s) which communicate(s) over the I2C bus as well. I am just doing this for a medical project. Markus _____ From: vicente_alvero_14@xxxxxxxxxxx<mailto:vicente_alvero_14@xxxxxxxxxxx> To: sugarshot@xxxxxxxxxxxxx<mailto:sugarshot@xxxxxxxxxxxxx> Subject: [SS2S-Main] volunteering Date: Sat, 15 Nov 2014 19:21:26 +0100 Hi all again, Although a long time do not talk about it, yet we continue the investigation of ablative materials. For the study of the material that will coat the nosecone of our rocket; Richard, Mattias and I already started last summer to work on it. Throughout this week, I've been talking to Hans, and he thought the possibility to also measure the temperature on the side of the wall that is in contact with the flame. Would be measured by an infrared thermometer. I am contacting you to see if anyone is interested, or know how, to attach an infrared thermometer with data logger that Liam is manufacturing for thermocouples. By this, we can obtain pairs of temperatures at the same point. Both outside and inside of the wall, in order to obtain among other data, values of thermal conductivity and heat capacity of each material. Thanks in advance for your cooperation and interest.