HI Quite true.
The down side is that I can buy a bag of 100 parts that are +/- 0.25 C at 25C for a lower delivered price as one piece of the calibrated parts. It’s a lot easier to glue down and throw away the cheap ones …. Bob > On Apr 5, 2018, at 10:15 AM, Edesio Costa e Silva <[email protected]> > wrote: > > If you use an "interchangeable" NTC like > https://br.mouser.com/ProductDetail/US-Sensor/PS103J2 you can skip the > calibration part. > > Edésio > > On Thu, Apr 05, 2018 at 09:20:56AM -0400, Bob kb8tq wrote: >> Hi >> >> By far the highest resolution sensor you will come across is a thermistor. >> It also has a pretty >> narrow range in terms of maintaining high resolution. That???s fine for >> something with a target >> temperature ( OCXO oven) and not so fine for monitoring outdoor temperature >> year round. >> >> If you want something that is pre-calibrated, then the IC based parts are >> the way to go. They >> are a much better answer to the ???general purpose sensor???? question. >> Mounting them and hooking >> up to them ??? errr ???. not quite so easy. >> >> One basic answer is to buy a bag of cheap thermistors and calibrate them >> yourself. They may >> have odd curves, but so far the entire bag looks about the same. That???s >> been true for a couple >> of bags bought randomly here and there. For a lot of things, a simple three >> point calibration will >> do pretty well. You still need to do a rational curve fit, but even that >> isn???t to crazy over limited >> ranges. >> >> Bob >> >>> On Apr 4, 2018, at 8:58 PM, Mark Sims <[email protected]> wrote: >>> >>> I recently (mostly) finished adding external environmental sensor support >>> to Lady Heather. You can use the sensor as the primary "receiver" device >>> or in conjunction with any of the "receivers" that Lady Heather supports >>> (except currently the HP-5071A which uses the same plot queue entries as >>> the environmental sensors). Heather supports humidity, pressure, and two >>> temperature values. >>> >>> I am currently using a dogratian.com USB-PA sensor with temperature, >>> humidity, and pressure. I am also designing a Heather specific board >>> (BME280, two thernistors, temperature controller interface, maybe a couple >>> of ADC channels, etc). Are there any recommendations for other >>> off-the-shelf sensors worth looking at? >>> >>> The main requirement is that the sensor should send data over a serial port >>> or virtual serial port or maybe ethernet. Ideally it would stream >>> readings at 1 Hz, but a polled device (like the dogratian.com devices) can >>> be accomodated. Also, it would be very nice if the temperature sensors >>> are small, responsive, and on leads that could be attached to whatever is >>> being monitored. >>> >>> Attached is a screen dump of the USB-PA running. Can you spot the furnace >>> cycling and sunrise? >>> <enviro.gif>_______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
