Temperature logger... Cheaper than Thermochron iButtons... - Page 1
Forum section: electronics / beginners

author: samgab
author_rank: Frequent Contributor
timestamp: December 25, 2011, 02:16:08 am
content: Hi. I have had to do some temperature logging lately.I'm trying to keep track of the temperature increases of various Cree LED builds I'm doing.I want to see what sort of temperature they reach with various types of heat sink setups.I don't have any temperature data logging devices.So I've been using 2 Fluke DMMs that measure - but don't record - temp; and setting an interval timer, and manually recording the temp of ambient and the measured probe temp each interval into a spreadsheet.But I'd like to get something that can be placed on the surfaces and will log the temp at set intervals.The Thermochron iButton would be perfect for my needs, but it is too expensive for me.Does anyone know of any similar type of temp logging device, that is cheaper, from a supplier that has international shipping?The temp range I would need to measure would be between about 10°-100° C. (20°-60° C worst case, but I've allowed some margin for extremes)Cheers!

author: samgab
author_rank: Frequent Contributor
timestamp: December 25, 2011, 02:17:39 am
content: This is the sort of thing I'm trying to achieve:

author: samgab
author_rank: Frequent Contributor
timestamp: December 25, 2011, 03:52:55 am
content: Actually, I can't find anything online more suitable than the Thermochron iButton, and I found that if I order a DS1921K starter kit and an extra DS1921G iButton from Digikey I get free shipping, so the price works out okay... I guess I'll just bite the bullet and go with that.

author: samgab
author_rank: Frequent Contributor
timestamp: December 28, 2011, 12:42:19 am
content: Well, I went to Digikey to try to purchase the thermochron items, but my order wasn't accepted. They kept emailing back and forth asking a whole bunch of questions about what industry I'm in, and what I want to use them for... (They're temperature loggers, I'm obviously going to use them to log temperature... All sorts of applications over the 10 year life of the devices). Anyway, it all got to be too much of a rigmarole, so I told them to cancel the order. I've ordered lots of stuff from the States without having to go through an inquisition about it.So now I'm thinking about this instead:http://www.extech.com/instruments/resources/datasheets/SD200data.pdfAmazon have it available with international shipping for a reasonable price.Anyone out there own and use the Extech SD200?Looks pretty good, has 3 inputs, is very accurate, and logs. So I think it will work as well for my purposes as the iButton solutions. The only drawback is, with the iButtons, I was going to put them in the fridge and the freezer to monitor temps over several days, and a few other applications that will be a bit more difficult with the SD200.But the SD200 has some advantages:SD card storage, so very easy to transfer the data, no extra connectors required.instant readout of the readings on the big screenall of the readings are simultaneous, so that makes charting the data a little bit easier.

author: amyk
author_rank: Super Contributor
timestamp: December 28, 2011, 11:30:07 am
content: How about a cheap MCU and a thermistor? You can add bulk SPI flash for logging tons of data if self-programmable internal flash isn't enough.