[SS2S-Main] Re: temperature measurement

  • From: "Nev Blyth" <nev.blyth@xxxxxxxxx>
  • To: sugarshot@xxxxxxxxxxxxx
  • Date: Tue, 25 Mar 2014 17:13:25 -0700 (PDT)

Great find Ken - new stuff popping up all the time it seems.  I may end up 
flying both modules now, and comparing performance.


The SSU S4 program looks excellent.




N
—
Nev Blyth
VK1HNB
0407 923 182

On Wed, Mar 26, 2014 at 10:22 AM, Ken Biba <ken@xxxxxxxxxxxxxx> wrote:

> I am currently liking this uBlox package from Sparkfun ... 
> https://www.sparkfun.com/products/11571 - for $40.    Small footprint, the 
> antenna seems sufficient.
> We are now using it on the S4 rocketry Arduino science payload that we are 
> doing with NASA and Sonoma State University.   s4.sonoma.edu.
> K
> Ken Biba
>> On Mar 25, 2014, at 4:14 PM, "Nev Blyth" <nev.blyth@xxxxxxxxx> wrote:
>> 
>> Cheers Ken - yes, your experiences are valuable indeed, and the Ublox 
>> certainly has the support for these kind of high dynamics applications.
>> 
>> Will let you know what I learn in the future.
>> 
>> N
>> —
>> Nev Blyth
>> VK1HNB
>> 0407 923 182
>> 
>> 
>>> On Wed, Mar 26, 2014 at 10:06 AM, Ken Biba <ken@xxxxxxxxxxxxxx> wrote:
>>> Nev:
>>> 
>>> Should do great for recovery location ... it is the trajectory location 
>>> that separates the GPS chipsets IMO.
>>> 
>>> Our flights are to 70-180k' MSL ... tickling Mach 3 ... so we are testing 
>>> the limits of modern comercial GPS chipsets.   So far the best has been 
>>> uBlox.   Altus Metrum used to use the MediaTek, but recently switched to 
>>> uBlox.
>>> 
>>> But this chipset does have "similar" specs - 515 m/s velocity, 40 km 
>>> altitude ... I would be curious about the dynamics.
>>> 
>>> I would have to dig out my old spreadsheets .. but there is such an obvious 
>>> difference between a chipset that is prepared to deal with dynamics and one 
>>> that is not.   Most of my testing ahs been with SiRF, uBlox and Trimble 
>>> chipsets.   Getting lock is not sufficient .. .what is interesting is that 
>>> reported location, under lock, is dramatically false for SiRF ... while 
>>> largely accurate for uBlox and Trimble (when set to high dynamic mode) up 
>>> to modest accelerations (<6-8 g).
>>> 
>>> K
>>> 
>>> Ken Biba
>>> 
>>> 
>>>> On Mar 25, 2014, at 3:54 PM, "Nev Blyth" <nev.blyth@xxxxxxxxx> wrote:
>>>> 
>>>> Hi Ken
>>>> 
>>>> (Apologies for getting OT here).
>>>> 
>>>> I've only flown the MTK3339 based module three times - on H & I motors. 
>>>> During those flights (3K ft only) I was not directly logging the NMEA 
>>>> stream on board - rather I was using a simple telemetry system to stream 
>>>> the NMEA to a recording ground station. Those flights showed valid data 
>>>> throughout, but admittedly, the dynamics were rather benign in the scheme 
>>>> of things.  I'll have a look at the altimeter log for velocities.
>>>> 
>>>> The axis of the GPS patch antenna was aligned normal to the vehicle's 
>>>> axis. Admittedly, my main motivation was recovery location, not trajectory 
>>>> recording, but I'll take what I get!
>>>> 
>>>> Nev B
>>>> VK1HNB
>>>> —
>>>> Nev Blyth
>>>> VK1HNB
>>>> 0407 923 182
>>>> 
>>>> 
>>>>> On Wed, Mar 26, 2014 at 8:20 AM, Ken Biba <ken@xxxxxxxxxxxxxx> wrote:
>>>>> Nev:
>>>>> 
>>>>> 
>>>>> Now I'm curious.   I fly the uBlox in large part because its signal 
>>>>> processing seems to do really well for high dynamic flight (and while it 
>>>>> has a spec limit of 50km, the factory says it will report above that 
>>>>> altitude, though with diminished precision).   It does stop reporting 
>>>>> above the spec limit of ~515m/s ... though does resume reporting when the 
>>>>> speed drops below that.
>>>>> 
>>>>> Many GPS chipsets perform poorly in high dynamic rocket flight ... since 
>>>>> the signal processing is biased to solve the 2D problem with high 
>>>>> precision rather than the fast changing 3D problem.   The uBlox has a 
>>>>> specific configuration parameter to set the movement model ... I don't 
>>>>> see that on the MediaTek manual.
>>>>> 
>>>>> Do you configure in default mode?
>>>>> 
>>>>> Ken
>>>>> 
>>>>> 
>>>>> 
>>>>>> On Mar 25, 2014, at 2:08 PM, Nev Blyth <nev.blyth@xxxxxxxxx> wrote:
>>>>>> 
>>>>>> Nathan - the adafruit GPS module is excellent - has flown multiple times 
>>>>>> in my high-power rockets and maintained a solid lock throughout the 
>>>>>> whole flight. If I recall, the module is programmable, has PPS output 
>>>>>> and the price is excellent.  Would be interesting to compare against the 
>>>>>> ublox offerings.  The external antenna connection is a bonus for me.
>>>>>> 
>>>>>> Cheers,
>>>>>> 
>>>>>> Nev. B
>>>>>> 
>>>>>> ___________________
>>>>>> Nev. Blyth, VK1HNB
>>>>>> Canberra, ACT, Australia
>>>>>> @nevblyth
>>>>>> facebook.com/nevblyth
>>>>>> 
>>>>>> 
>>>>>>> On 26 March 2014 05:40, Nathan Asdourian <rawliquid@xxxxxxxxx> wrote:
>>>>>>> you would be much better off with a ublox that is fully configurable 
>>>>>>> and reprogrammable,  not to mention the latest version has a compass 
>>>>>>> module in it.... i think it's more than $40 though it is the unit from 
>>>>>>> 3drobotics.com and what i use in my helis
>>>>>>> 
>>>>>>>> On Mar 25, 2014 10:47 AM, "Rick Maschek" <rickmaschek@xxxxxxxxxxxxxx> 
>>>>>>>> wrote:
>>>>>>>> Hi Nathan,
>>>>>>>> 
>>>>>>>> and this may be going up on our next Near Space balloon launch: 
>>>>>>>> 
>>>>>>>> http://www.adafruit.com/products/746 
>>>>>>>> 
>>>>>>>> Are bitcoins worth anything anymore?
>>>>>>>> 
>>>>>>>> Rick
>>>>>>>> 
>>>>>>>> 
>>>>>>>> On Tuesday, March 25, 2014 6:37 AM, Nathan Asdourian 
>>>>>>>> <rawliquid@xxxxxxxxx> wrote:
>>>>>>>> Please forgive me if these items are irrelevant due to the extremes 
>>>>>>>> needing to be dealt with but I just saw a new board get released here 
>>>>>>>> a few weeks ago,  and all the related things seem to be under $20
>>>>>>>> http://www.adafruit.com/index.php?main_page=adasearch&q=thermocouple
>>>>>>>> And of course if anyone has some bitcoin stashed away,  they will 
>>>>>>>> accept that for payment...
>>>>>>>> On Mar 24, 2014 9:20 PM, "Lampe, Mattias SLC CT PEK" 
>>>>>>>> <mattias.lampe@xxxxxxxxxxx> wrote:
>>>>>>>> Hi Richard,
>>>>>>>> 
>>>>>>>> my personal choice would probably be to use an integrated chip that 
>>>>>>>> does everything, including D/A-conversion, e.g. the MAX6675:
>>>>>>>> 
>>>>>>>> http://item.taobao.com/item.htm?spm=a230r.1.14.48.TLryFm&id=13831142184
>>>>>>>> 
>>>>>>>> Since it may be more convenient for you to use the existing DAC, you 
>>>>>>>> may prefer one of the older chips with analog output, though. AD595 
>>>>>>>> would be a good choice:
>>>>>>>> 
>>>>>>>> https://www.sparkfun.com/products/306
>>>>>>>> 
>>>>>>>> Of course you'll need to have a loot at the datasheets to see whether 
>>>>>>>> the devices match the temperature range you need.
>>>>>>>> 
>>>>>>>> Hope it helps.
>>>>>>>> 
>>>>>>>> 
>>>>>>>> Have a good day!
>>>>>>>> 
>>>>>>>> Mattias
>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>>> >-----Original Message-----
>>>>>>>> >From: sugarshot-bounce@xxxxxxxxxxxxx [mailto:sugarshot-
>>>>>>>> >bounce@xxxxxxxxxxxxx] On Behalf Of Richard Nakka
>>>>>>>> >Sent: Monday, March 24, 2014 10:33 PM
>>>>>>>> >To: sugarshot@xxxxxxxxxxxxx
>>>>>>>> >Subject: [SS2S-Main] temperature measurement
>>>>>>>> >
>>>>>>>> >For an upcoming motor test, we would like to use thermocouples
>>>>>>>> >(k-type?) to measure motor casing and nozzle temperatures.
>>>>>>>> >We would like to use an 8-channel DATAQ unit for the data acquisition.
>>>>>>>> >
>>>>>>>> >We understand there are challenges to this due to small voltage
>>>>>>>> >signal, non-linear temperature-voltage relationship and the need (?)
>>>>>>>> >for a reference junction compensation.
>>>>>>>> >
>>>>>>>> >Question to list members: Can anyone give advice on how to do this?
>>>>>>>> >What kind of amp would we need? Could anyone be of assistance in
>>>>>>>> >designing/building such?
>>>>>>>> >
>>>>>>>> >
>>>>>>>> >thanks in advance
>>>>>>>> >Richard
>> 

Other related posts: