Custom Time Intervals on Graphs and Data Exportation


#1

Dear Cayenne community,

First of all, I would like to say thank you to the Cayenne developers and their eagerness to improve their product. The Cayenne interface is very slick, user friendly, and capable - I firmly believe that this is the start of a great product.

With that being said, I would like to make a suggestion to the developers. I would like the ability to have smaller time intervals on this project while Cayenne is sensing data from an output connected to the Raspberry Pi or an Arduino. My personal desire for this is that for part of an honors project I am working on for my engineering degree, I would like to measure the change of the weight of an object over time. Using the custom time intervals on a graph, I can see how much the weight is changing and measure - most important to me - how fast the weight is changing.

I saw somewhere that data exportation is coming - with that being said, could we specify what data we want at the previously defined time intervals? For example, if I specified a time interval of 0.1 seconds, could the exported data be formatted something like

Time - - - - - Weight
0.1 - - - - - - - 5
0.2 - - - - - - - 10
0.3 - - - - - - - 15
.
.
.

That being said, how much data could we in theory export? Would it be the data from just one run of a sensor? The last hour? A user-specified interval? All the data up to that point collected from the sensor?

Thank you Cayenne development team and I look very much forward to future designs of your product and improvements. If you need more clarity anywhere, let me know and I will adjust the post accordingly.

Yours truly,

Jacob


#2

Hi Jacob,

We’re very glad you are enjoying Cayenne! It’s always good to hear real users who enjoy the product, it makes the long hours from the Cayenne team worth it :slight_smile: P.S. we think it is the start of a great product too!

What is the time interval you are looking for? Is data every 1 second, or 2 seconds, not sufficient?

With data exportation, we will basically do a data dump of all data we have for the given set (sensor) we have at that time. It would be up to the user to sort / filter the data for example in an excel pivot table.

-B


#3

Hey @bestes sorry for the time it has taken me in responding.

Well, the reason why I was thinking that there should be smaller time intervals was for the reason that the weight I would be measuring is changing due to a liquid being poured into a cup on the scale in real time. My ultimate goal would be to calculate the flow rate for how fast the water is being poured into the cup. Furthermore, I am going to be working on another project where I am using a Liquid Flow Meter (see: https://www.adafruit.com/products/828) to measure the flow of a liquid.

In your opinion, do you think I should be able to calculate flow rate adequately without having to worry about smaller time intervals? The standard time intervals are fine for constant flow rate, but I am just concerned about flow rate that is not always constant. My instincts say data points at small time intervals would yield greater accuracy, but I would like to know your thoughts. If you deem this modification superfluous to the program, no worries.

Oh ok, that is very good and nice to know. Will there ever be the option of resetting stored data for the user so it does not have to be as tedious combing through possibly hundreds of data points to get the ones you need? What are your thoughts?

Thanks @bestes. Again, great product and great interaction with the community here. It is very unique and a very admirable trait to have with this kind of product. Looking forward to your response.

~ JayMasters


#4

For using the Pi I would say it’s not going to be accurate enough. If you use Arduino you can capture and calculate then send the data to the dashboard in an interval just fine.


#5

Hey @JayMasters,

I would agree with @ats1080s that Arduino would be more accurate for your situation, you should be able to control the interval in your code. Although, I’m sure we have a limit as to the interval that our servers would allow, I just don’t know it. I’ll look into that.

Perhaps there will be option in future iterations of data export feature. This first iteration is basically a data dump of all data we have for the device, and normalization / organization of the data would be up to the user. Would love to hear what you think for improvements after trying out the data export feature (should be released later today!).

Thank you, I will pass this along to the Cayenne team, everyone works hard and we love to hear positive feedback :slight_smile:
-B


#6

I think it would be useful to have a user-definable polling rate (within the capabilities of the server).
In my case - I would like the data to be transmitted less often. No need to check every couple of seconds when I am happy for it to check every 5 minutes or so.


#7

Any updates regarding the download data option? I am looking forward to getting an excel file of data.


#8

You can download data by clicking the download icon in the top right corner of a history graph widget.

Let us know what you think!

-B