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

[time-nuts] Environmental sensor recommendations

By comparing how much the DAC voltage changed with temperature. Heather can calculate the OCXO EFC sensitivity (Hz/volt). Combine that with the DAC setting and you get Hz/degree. --- > How did you measure temperature sensitivity

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

[time-nuts] Environmental sensor recommendations

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 assumed the main contributor was the OCXO. I didn't try mod-ing any other Tbolts. I also tried temperature stabilizing the power supply and it seemed

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

[time-nuts] Environmental sensor recommendations

Digital temperature sensors have some advantages (like nice factory calibration), but also so issues. The IIC/SPI ones need to be mounted to a PCB and also have quite a bit of thermal mass. They also need 4-6 wire cables. They are hard to attach directly to a point that you want to

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:

[time-nuts] Environmental sensor recommendations

Long ago I did a board for evaluating high power LEDs and drivers. Iit was called Luxor and if you look through the Lady Heather code, you will see references to it. It has all the functionality (and them some) needed for an environmental sensor and temperature controller. It has 4 dual

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,

[time-nuts] Environmental sensor recommendations

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... tis' not something Heather wants to work with. Also, none of them seem to do air pressure. They do have a device that does temperature and humidity and can emulate

[time-nuts] Environmental sensor recommendations

Lady Heather has a very nice temperature control PID in it (designed by Warren Sarkisen). It was originally designed to stabilize the temperature of a Thunderbolt GPSDO. The standard Thunderbolt OCXO is rather temperature sensitive. The standard/simple implementation involves sticking the

[time-nuts] Environmental sensor recommendations

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 stability. https://www.crossco.com/blog/basics-tuning-pid-loops Many simplistic approaches use an ON-OFF controller to turn on

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

[time-nuts] Environmental sensor recommendations

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