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Post by Sean Curry on Apr 14, 2017 8:19:20 GMT -7
How are teams planning to synchronize the clocks on the still image and video payloads? It seems that it would be good to have accurate timestamps on the images, but the Pi doesn't have a real time clock. Are you planning to set the clocks with the date command on powerup just before launch or are their other ideas?
Thanks, Sean Oregon Tornadoes
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Post by leviw on Apr 14, 2017 11:07:13 GMT -7
That's a good point about accurate timestamps during the eclipse, and a good question of the best way to do it. I'm aware that various real time clocks exist and aren't expensive or difficult to use, but there hasn't been much discussion about this. As you mentioned, it's also possible to just set the correct time from the laptop. But it's an extra step and would be easy to forget.
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Post by David MSGC on Apr 15, 2017 16:49:55 GMT -7
There were real time clocks provided with both Raspberry Pis(video and still image payloads) and the SD cards are configured to use the real time clock. On the RFD system, each time you do a signal test it will print the time on the pi and on the ground station computer to give an idea of how close the clock are to each other just to tell you if one of the clocks is not accurate, ie rtc battery died and have very different time than the laptop. We could use the RTC to sync or set the RTC time from the laptop. Setting up the RTC is different between Rasbian Wheezy and Rasbian Jessie. The .iso provided from MSU has Wheezy configured to use the RTC, the fake hw clock is disabled so if you enter "date" at the command prompt it will give the system time, this will be the time from an NTP server if you are connected to the internet and the time of the RTC if not connected to the internet. "hwclock -r" will display the time of the RTC and "hwclock -w" will write the system time to the RTC if you are connected to the internet. All the clocks were set in Montana and will be on Mountain Standard Time even if you change the time zone in raspi-config or tmzdata. You can update the time by connecting to the internet, check the time with "date", and then set the clock with "hwclock -w" The time stamps on the rfd files created and photo names are from the the time on the RTC. FYI the new iso for the video system will be using Jessie Lite and setting up the RTC will be different than regular Jessie and regular Jessie is different than Wheezy. I am currently working on adding the RTC functionality to the iso. Reading the time (other than the time stamps already used in RFD or video) or any time syncing will have to be implemented by the users.
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Post by Sean Curry on Apr 16, 2017 14:30:05 GMT -7
Thanks David, this is very helpful information.
Sean Oregon Tornadoes
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