Re: [time-nuts] Environmental sensor recommendations

Hi Just to be very clear about this issue: Your room temperature “moves” at a rate dimensioned in degrees / hour (like 2 degrees / hour) and the period should be out in the half hour to couple of hours range. Put another way, it’s a 1,800 to > 5,000 second sort of thing. Operating with

Re: [time-nuts] Environmental sensor recommendations

t is the DAC. > > So is there a better one that can be used to replace it? > > David > > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of ew via > time-nuts > Sent: 05 April 2018 10:43 > To: time-nuts@febo.com > Subject

Re: [time-nuts] Environmental sensor recommendations

How did you measure temperature sensitivity Bert Kehren   In a message dated 4/6/2018 3:40:18 AM Eastern Standard Time, hol...@hotmail.com writes:   I replaced the OCXO on one of my Thunderbolts with an Oscilloquartz 8663 and the temperature sensitivity went down by about 2/3, so I always

Re: [time-nuts] Environmental sensor recommendations

com Subject: Re: [time-nuts] Environmental sensor recommendations I respectfully disagree. The OCXO is not the temperature problem with the Tbolt. It is the DAC. Again this is not a product developed for time nuts it did an excellent job for its intended purpose. Over a year we worked on the Tb

Re: [time-nuts] Environmental sensor recommendations

I would like to put in a good word for the DS18B20 temperature sensor. It consumes very little power, uses the "1-Wire" protocol, and is available pre-wired in a variety of configurations, for example this https://www.adafruit.com/product/381 and this https://www.adafruit.com/product/642

Re: [time-nuts] Environmental sensor recommendations

> Are there any recommendations for other off-the-shelf sensors worth looking > at? Mark, Check out ADT7420: http://www.analog.com/media/en/technical-documentation/data-sheets/ADT7420.pdf A useful white paper, including comparison of NTC RTD and IC sensors:

Re: [time-nuts] Environmental sensor recommendations.

I've used a few Pt100 RTDs over the years for gas flow temperature control in the 200-300C range.  At 0.385 ohms per K, the challenge of managing the noise is a lot tougher than a cheapo NTC thermistor, but I needed repeatability and stability. http://www.farnell.com/datasheets/2278399.pdf I

Re: [time-nuts] Environmental sensor recommendations

I respectfully disagree. The OCXO is not the temperature problem with the Tbolt. It is the DAC. Again this is not a product developed for time nuts it did an excellent job for its intended purpose. Over a year we worked on the Tbolt using HP 10811, OSA 8600, FRK Rb, M100 Rb with excellent

Re: [time-nuts] Environmental sensor recommendations

Mark! On Thu, 5 Apr 2018 07:13:49 + Mark Sims wrote: > I looked at the TEMPer devices, but almost all of them seem to be HID > devices that emulate a digi-monkey typing on a keyboard... NTPsec uses them in a polled mode. Very easy to work with. # temper-poll -c

Re: [time-nuts] Environmental sensor recommendations

I will comment on a couple postings: On Wed, Apr 4, 2018 at 8:00 PM, Tisha Hayes wrote: > > I would suggest that if you are looking at taking temperature sensor data > and attempting to control some type of heating/cooling device that you > implement a PID loop for

Re: [time-nuts] Environmental sensor recommendations.

, holding the temp constant) for cost. Dan On 4/5/2018 12:00 PM, time-nuts-requ...@febo.com wrote: Message: 11 Date: Thu, 5 Apr 2018 09:44:48 -0500 From: John Green<wpxs...@gmail.com> To:time-nuts@febo.com Subject: Re: [time-nuts] Environmental sensor recommendations. Mess

Re: [time-nuts] Environmental sensor recommendations.

Hi Thermocouples are *really* low output voltage devices at “normal” temperatures. That gets you in to fairly fancy measurement setups ( no “just strap it to an ADC input” stuff). They also require cold junction compensation. They measure offset temperature to that junction. You do a lot of

Re: [time-nuts] Environmental sensor recommendations.

On 5 April 2018 at 15:44, John Green wrote: > Why has no one mentioned thermocouples? > I had some experience with thermistors a few years back designing thermal > attenuators and equalizers for CATV. NTC thermistors can have a large > change of resistance for a unit change in

Re: [time-nuts] Environmental sensor recommendations

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

Re: [time-nuts] Environmental sensor recommendations.

Why has no one mentioned thermocouples? I had some experience with thermistors a few years back designing thermal attenuators and equalizers for CATV. NTC thermistors can have a large change of resistance for a unit change in temperature. They aren't linear, but there are formulas for computing

Re: [time-nuts] Environmental sensor recommendations

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

Re: [time-nuts] Environmental sensor recommendations

- Original Message - From: "Peter Vince" <petervince1...@gmail.com> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Thursday, April 05, 2018 6:24 AM Subject: Re: [time-nuts] Environmental sensor recommendations > Hi Mark,

Re: [time-nuts] Environmental sensor recommendations

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

Re: [time-nuts] Environmental sensor recommendations

Hi Mark, SparkFun have some boards that have multiple sensors. They *used* to do one with a USB connection that had temperature, pressure, humidity, and light! But I see that is now "retired" ( https://www.sparkfun.com/products/retired/8311 ) and has been replaced by an Arduino shield:

Re: [time-nuts] Environmental sensor recommendations

Mark, Thanks for doing this ! Aside of the "commercial" sensors, will you open the API or data format for the community ? In such way, we could tailor our existed "telemetry devices" to be connected to LH ! I see lot of perspectives here. Seismic, radiation, lighting, main, air, light,

Re: [time-nuts] Environmental sensor recommendations

> Are there any recommendations for other off-the-shelf sensors= > worth looking at? Consider the TEMPer USB units from eBay. Their main advantage is low cost. They have a temperature sensor in a thumb drive size USB module. At least one model comes with a slightly bulky sensor on the end

Re: [time-nuts] Environmental sensor recommendations

Yo Mark! On Thu, 5 Apr 2018 00:58:50 + Mark Sims wrote: > Are there any recommendations for > other off-the-shelf sensors worth looking at? I use several of the TEMPer series. http://pcsensor.com/usb-thermometer/temper1f.html The TEMPer1F has a local and a remote