Electronics, Crary Science Lab and Ob Hill Climb

I haven’t posted in what seems like forever, sorry.  I have been feverishly working on the prototype.

Note that I am about to bore you with some technical electronic stuff.  If you aren't up for it scroll down and read more about other Antarctica stuff  Ok, here goes.

I have been consumed the last few days by a bug that is proving difficult to sort out.  I have figured out a work around but really would like to know why it isn’t working per manufacturer specification.  I have emailed the company informing them of the anomaly and hope one of their FAE’s (Field Application Engineers) can shed some light on why the device is replying with 2 valid bytes of data out of 7.  In the photo below you can see the prototype AWS and the o-scope probes on the IC that is giving me issues.  

Here are three screenshots from the o-scope showing the prototype master processor querying the Real Time Clock (RTC) IC pictured above.  For those of you who have never looked at this type of signal before I will try to break it down.  The Orange line is the Clock signal driven by the Master.  The other signal is the data line.  In this IC the data line will let us know the time and date.

In the first screenshot above you see the blue line is up and down.  Up is a 1 and down is a 0.  1's and 0's are how these things talk.  From left to right there is a data (1 or 0) for each high of the clock.  So the left is the start, when the Blue line falls the first time , then 1101000, then the next pulse signals the slave acknowledges the transfer.  Then the master sends the address it wants to read.  I want to read location 0, so the next is all zeros and an acknowledge at the end.

Here the RTC replies. In this screen this is seconds and minutes of the RTC.

And here is the issue.  See the blue line is low almost all of the time.  This is where day, month and year should be.  It is all zeros.  But it isn't internally to the RTC.  I know this because if I request the IC for only 2 bytes at a time is 4 separate reads I get valid data back.  Why not just do that always, because there is a chance I could ask first for seconds and minutes and get 59 minutes and 59 seconds.  Then ask for hours and day but the seconds just rolled over to 00:00 and now I am off by 59 minutes ahead because the hour just went up by one when the others rolled over to zero.  I have dreamed up a work around by asking a few times in a row for all 7 pieces of data then looking to see if the time just rolled over or not.  If not, keep the last request.  This is not ideal but I may have to go this route if the FAE cannot explain the problem in their IC.

Enough geek speak for now.  Since I have been working approximately 9am to 9pm in the lab with meal breaks I figure I could show you guys where I am working.  The crew here has both an office and a lab space in Crary Science Laboratories.

https://en.wikipedia.org/wiki/Albert_P._Crary_Science_and_Engineering_Center

We are in Phase II of the building, this is the middle portion of the building as you go down the hill towards the Ice.  Matthew, Dave and Marion occupy the office; while I spend my time on the ESD safe matts in the lab.  The prototype doesn’t have a chassis so it can be susceptible to damage from an electrostatic discharge event.  I mentioned the Zap events in an earlier post.

Tonight, after dinner I had to go dumpster diving in front of Crary.  The power supply in the prototype does not have the correct inductor in the circuit.  In hopes of finding something to swap it with I went into the Electronics scrap bin and pulled out a few circuit boards.  Tomorrow I will search them and compare with the calculations that Forbes is working on back at the College.  I briefly looked over the boards and the options on there do not look promising.  I make have to make friends with NASA down here and see if they can help me out.

Tomorrow I may get to take my third Helo flight out to a station.  We need to visit Lorne again to sort out a communication issue that the site is having.  Dave and I were able to get a backup modem working in the lab and will take that one to the site tomorrow, WEATHER PERMITTING.

On a different note, Matthew and I did take a break on Sunday to climb Ob Hill.  The hill is over 700 feet tall.  It was quite a climb in the heavy ECW gear.  The visibility that day wasn’t the best we have had but the views were still incredible.  The grade is quite steep and slippery with the loose volcanic rock on the trail.  On the climb up we crossed the site of the Nuclear Power Plant that use to power the station.  It was shut down and removed in the 1970’s.

We continued to the top and took breaks as needed.

Once at the top we took some pictures and also some time to soak in the views.

Look at the back of this photo and you can see the faint blue line across the horizon.  This is the Ice edge to the sea.  You can also see the line that the Ice Breaker broke in to McMurdo for the cargo ship, The Ocean Giant, and the research vessel to get into town.

It is truly a beautiful place!

(Partly foggy that day, so view is not crystal clear).