I’ll be using the sck for a project for indoor environment control. I am sure the sck usual update rate works fine in the real world, and temperatures don’t change that suddenly. But for demonstrating my project, I plan to try some sudden temperature changes (with hair dryer or ice pack), and want to observe the results.
How often does the sck update it’s environment parameters? Every hour? Minute? Second?
Thanks,
Drew
Hello Drew,
by default the Smart Citizen Kit takes a reading every minute and publish it on-line. This is defined on the firmware here:
The reading intervals and update times can be adjusted using the configuration tool using the Chrome App as explained here:
http://docs.smartcitizen.me/#/start/adding-a-smart-citizen-kit
However this tool limits you to a minimum 1 minute interval between readings.
In order to set the interval time below 1 minute you will need to use the Smart Citizen Kit command line and set set time update 20. However going under 20 seconds updates can make the firmware unstable some times.
http://docs.smartcitizen.me/#/start/the-sck-command-line
We plan to work on this in the future to allow close to real-time updates for science and education applications.
Let us know how it works,
Guillem
Can anyone say, according to this thread, if update intervals can safely be made smaller than 60 seconds?
Hi @dixon1e,
Not at the moment. The configuration of the interval is currently set so that you can only increase it over 60s, but not below it, unless you modify the firmware. The idea is that you would want your battery to last longer, and for this you reduce the sampling frequency.
However, at this very moment, you can use the shell tool to monitor the data as fast as possible and log it into the sd-card or to a text file in a computer. Check the instructions here and let us know if it helps!
The command would be for logging into the sdcard (this command goes inside the SCK’s shell):
monitor noise -sd
And for logging with a pi or a computer attached (this command goes in the computer’s shell):
echo "monitor noise" > /dev/<SCKs_port> && screen -L /dev/<SCKs_port>
You can also build more complex setups with scripts in python (check this example).
Keep in mind the following for the microphone: we sample ~23ms at 44,1kHz and we process that sample (FFT and so on) in ~250ms. While we process, we don’t sample, and this means that roughly every second we take 3 to 4 ~23ms samples and process them, but the sampling is not continuous, since we basicly cannot process as fast as we sample due to the SAMD21 capabilities.
Regards,
Óscar
1 Like
Hello Óscar,
Thanks so much for you reply, please pardon the COVID induced delay in responding.
This is very helpful indeed, and I am very thankful for your thoughtful reply. I have started re-reading the documentation, and I see a project like “Almabike” discusses motion sensing as a trigger to speed up the interval. So, there is certainly much to learn again.
As I was looking through the documentation, I also see a lot of work on enclosures has happened in the last year. That’s terrific as well!
One thing happening, is I see some broken links in the documentation. To start engaging, I plan to create issues for documentation fixes, and learn how to do Pull Requests.
I hope to give useful work to the project.
Warmest regards,
dcd
Hi Dixon,
That’s great, please feel free to post any issues, improvements and to modify files yourself and put a pull request. We know there are still some issues in the docs, and we fix them as we go, so thanks for the patience and the nice attitude towards making it better.