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Telecon tomorrow (Thursday) @ 5 pm Eastern time

Hi all!

Telecon tomorrow (May 5 in North America, May 6 in Australia) at the regular time: 5 pm Eastern (2 pm Pacific, 11 am Hawaii, 23.00 European, 7 am Eastern Australia). Andrew Macdonald has now made some actual progress testing his ALTAIR photodiode readout / transimpedance amplifier boards. I have some updates on some new large lightweight flexible solar panels (for future balloon-top usage!) that have arrived here for testing, and also some more progress has been made with operation of the two Raveon M8S 144 MHz transceiver boards. More discussion items for tomorrow's telecon include: flight/telescope plans and tests; construction and lab tests of the new gondolas/payloads; light sources and light source modelling; goniometric and pre- and post-flight calibration; propulsion work; nanosat bus and payload solid models; computing / website / TWiki forums and e-mails; grant applications; and recap of schedules. I'll send the progress report and plots before the telecon tomorrow.

Here's how to connect:

1) Open Skype on your computer (note that of course, you should first install Skype, http://www.skype.com, on your machine if you haven't already).
2) In the "Contacts" menu, add me ( jalbertuvic ) as a contact, if you haven't already.
3) Just wait for me to Skype-call you at the usual time (5 pm Eastern, 2 pm Pacific, etc).
4) If there is any trouble, or if you don't get a Skype-call for some reason and would like to join, please just send me an e-mail (jalbert@uvicNOSPAMPLEASE.ca).

Here's the tentative agenda:

I) Flight & telescope plans, and upcoming tests
II) Construction, drop tests, and other tests of the new gondola and payload
III) Diffused light source and its modelling, pre- and post-flight calibration, and goniometric calibrations
IV) Solid modelling
V) Computing/website, including recent flight control and simulation progress
VI) Grant applications

Talk to you all tomorrow, thanks!!!

-- Justin Albert - 2022-05-05

Hi all,

My apologies for the delay! -- here's the update on recent ALTAIR balloon work, minutes of the meeting 2 weeks ago on Apr. 21 (attendees Arnold Gaertner [NRC], Liviu Ivanescu [Sherbrooke], and me), and a reminder of the telecon in 10 minutes(!) from now:

Andrew Macdonald produced the following report yesterday summarizing his studies so far of the one populated (out of three fabricated) ALTAIR photodiode readout / transimpedance amplifier (TIA) boards:

He has been testing the front end TIA using the following setup (photo taken yesterday):

fairly similar to his setup as of a month ago:

I replied yesterday:

``Thanks!  Your proposed steps for the next tests look very good to me!
  And also I will call Tek tomorrow to check on when they will send my
  Keithley 2450 back, so we can then check if the issue you issue you are
  seeing with your 2450 is specific to your own 2450, or is a more general
  issue with all 2450's.

``I believe the 'full-range voltage + resistance -based source for more
  accurate testing' that you mention can easily be made on a breadboard
  with the materials in the box I handed to you on Friday and the circuit
  diagrams I sent on Sunday.''

(BTW, the circuit diagrams I sent on Sunday, using the materials in a box I handed to Andrew on Friday, are shown in:

). Then I followed up:

``Hi again!  One _very_ important thing that could also be quickly checked
  is if your statement 'The latch-up issue shouldn't happen in the final
  application when a photodiode is attached' is true -- by just attaching
  a photodiode! Does it latch up when a little photodiode (i.e. basically
  any one that you have laying around -- I could give you a Thorlabs
  FDS-100 if you need a random one to try) is attached?  And do the TIA
  outputs seem to make sense in general whan that is done?  (Of course,
  one can't actually calibrate the circuit like that since neither the
  photodiode nor whatever light is shining into it would be precisely
  calibrated at all -- but one can still certainly make sure that the
  output of the TIA makes sense in general!!!)  The above should
  definitely be done/checked ASAP -- before even populating a second

His reply, and my reply to that, are:

On Wed, 4 May 2022, Andrew Macdonald wrote:
> I have a photodiode, similar in spec to the FDS-100, already connectorized and ready to go.  I just haven't
> had the chance to plug it in yet. I'll try that tomorrow morning.

Excellent!!! :)

> As for the 2450, I suspect the issue might have something to do with the mains earth-ground connection, as I  
> also have our high-res DMM and a power supply (both mains-powered) plugged into the board.  They allegedly
> have isolated outputs, but that can mean different things to different folks.  I have substituted batteries for the 
> supply to no avail, but I haven't tried substituting the DMM for a handheld yet... Also, if Adithi needs to
> use a 2450, she can use ours, but only in the shop at the student bench, as we make a point of not loaning it out.

Yep!  (And I'll bet you're right about mains earth-ground being the cause.)


So ... things are now moving along again on that front!

We have some new solar panels (and a controller, which we'll need to re-make for balloon use) -- with photos at:


I'll mention more about these new solar panels (and we should have some more tests done with them) in 2 weeks from now.

The two 144 MHz Raveon M8S data modem transceivers are still here in my office (together with the LiPoly batteries that power them), and hopefully this weekend I will get a chance to test Colton Broughton's most recent code updates for them, which can be found in:


(as compared with his older code within https://particle.phys.uvic.ca/~jalbert/ALTAIR_M8S_Colton17nov21/ ).

Our new summer NSERC USRA student Adithi Balaji, Colton Broughton, Sarah Alshamaily, and Will Stokes have also completed installing AIFCOMSS ( https://github.com/ProjectALTAIR/AIFCOMSSwithCUPredictorTest ) on their laptops. I've updated AIFCOMSS to work with the recent Cesium v1.83, as well as the instructions, and they all report success with this update and those instructions. The next two things that we know most definitely will need updating (or, rather, creating) are the station-keeping software for AIFCOMSS, and the online command-handling within the onboard Arduino software -- and I'll also be working on those over the next 2 weeks.

Regarding the latest news on our four Radiometrix SHX1 144 MHz transceiver modules that were returned to us from Radiometrix (following their firmware update to fix the BUSY output):

and the problems that Colton found with them (i.e., that of the 12 radio TX to radio RX permutations between those 4 boards, only 3 of the 12 permutations work, 3 of the other permutations give spotty connections -- e.g. only around 1 out of every 5 characters gets successfully transmitted -- as if one is transmitting and the other is receiving on neighbouring channels, but not the same channel..., and the remaining 6 permutations do not successfully receive any transmitted characters) -- we sent an e-mail to Radiometrix to ask about this about 7 months ago. They then sent back an e-mail a week later asking for more information, and Colton replied to them the next day providing the info (just a query about what logic voltages we were using -- we've being using 5V TTL from our Arduino Megas). Radiometrix has not replied to us since that e-mail reply sent to them 28 weeks ago, and thus I pinged them 26 weeks ago to follow up, and again 19 weeks ago -- and Radiometrix hasn't replied to those yet either. I will be pinging Radiometrix on this yet again next week.

We also still need to test out our new DFRobot SEN0177 payload aerosol monitors that we have here:

Engineering students Josh Gage and Evan Moore found that the "wings" that Josh had found in the laser diode light output distributions:

were due to how the diode was mounted in the heat sink. When the diode is mounted properly and carefully, the wings go away.

We also have our 10 Hamamatsu S12698-01 photodiodes and 3 Thorlabs FDS100-NOCAN photodiodes (those Thorlabs ones have their windows removed) here in Victoria:

I've given them to Evan to try out -- he's taking a few weeks to ramp up, and will produce some linearity, etc., plots from them soon.

The survey-tripod-mounted device to cross-check yaw-pitch-roll information from the gondola (e.g., on days before/after flights) is also constructed now, thanks to Mark Lenckowski -- photo at:

and all that remains to be done is to finish the small fitting between the device and the bottom of the payload. The purchased hardware in it includes both the survey tripod (http://www.cpotools.com/cst-berger-60-alwi20-o-aluminum-tripod-with-quick-release--orange-/cstn60-alwi20-o,default,pd.html), two adjustable angle mounts (http://www.thorlabs.com/thorproduct.cfm?partnumber=AP180), and a rotation mount (https://www.thorlabs.com/thorproduct.cfm?partnumber=RP01). That last fitting to attach (temporarily, pre-or post-flight) the upper adjustable angle mount to the payload landing gear has been started and will be completed here in the next couple weeks.

We're currently revising the draft initial contractual agreement from our colleagues at Globalstar Canada regarding 2 initial SPOT Trace devices (and their service plans) for the educational side-project for the upcoming NATO SPS application, in which classrooms in elementary and high schools could launch company-donated SPOT Traces using party balloons (or a more environmentally-friendly version thereof), and track them to learn more about winds at different levels in Earth's atmosphere.

Houman will send Cordell and/or us updated sections of his master's thesis soon -- that information will be extremely useful to us going forward. Also, Susana and Nathan, it would be very helpful for us all to get the JHU students' final writeup when you have a chance.

Next grant application will be a NATO "Science for Peace and Security" application (together with Australian colleague partners).

Our next telecon is in 10 minutes from now! -- see below for Skype instructions.

Cheers, talk in 10 mins (!) from now -- thanks all!


-- Justin Albert - 2022-05-06

Title Telecon tomorrow (Thursday) @ 5 pm Eastern time
Forum ForumGeneral
Topic attachments
I Attachment History Action Size Date Who Comment
JPEGjpg ALTAIR_AndrewMacdonaldPhotodiodeReadoutBoardTIATestingSetup_4may22.jpg r1 manage 2617.2 K 2022-05-05 - 05:04 JustinAlbert Photograph, taken 4 May 2022 by me, of Andrew Macdonald's testing setup for the transimpedance amp front end of the ALTAIR photodiode readout board (purple)
JPEGjpg PossibleCircuitDiagramsForPDVS2miniBasedCustomFemtocurrentSource_2may22.jpg r1 manage 3057.1 K 2022-05-05 - 22:30 JustinAlbert Possible circuit diagrams for PDVS2mini-based custom femtoamp current source, drawn 2 May 2022 by me
PDFpdf TIA_DAQTestReport2022-05-04.pdf r1 manage 106.0 K 2022-05-05 - 05:06 JustinAlbert Report from Andrew Macdonald, sent on 4 May 2022, describing his testing so far on the transimpedance amp front end of the first (of the three) ALTAIR photodiode readout board
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Topic revision: r4 - 2022-05-06 - JustinAlbert
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