I’m making a project with Blynk in which I need to read sensor data (voltage from potentiometer) and plot that values in a SuperChart widget.
The problem is that the display/reading rate of the SuperChart it’s to slow, and in the widget options there is no way of change the reading rate (like in the others widgets (for example “value display”)).
I’m sending the voltage from the pot through virtual pin every 10 ms but the graph refresh like every second.
Please help me!!!
I believe that 1 second refresh is the set limit (possibly so as to not flood the Cloud Server)… Sorry, nothing can helped for now…
Besides, how would you even utilize a 10ms chart reading? it would scroll by to fast to make any sense.
Not to mention flooding the system and kicking in the governor like protection, else nothing else would really work anyhow due to disconnection.
Trust me on this… I have tried to push virtual writes that fast (to LED widgets, not the SC)… it barely works on a Local Server, and only if nothing else is trying to run.
Thank you for your response Gunner
So, the conclusion is that I can push the data as fast as I like with other widgets (I know that if the reading rate it’s to fast I would probably flood the cloud server) but with the SuperChart the reading/display rate it’s fixed to 1 second??? It’s that right??
You can try no guaranties
Yes… but whether that can or will ever change is up to the developers (no need to request again… they read these posts… )
Thanks for everything Gunner
I hope the developers read this. I think it’s so important the fact that, in some applications, the plot rate it would have to be faster.
A minimal step on the SuperChart widget is 1 second, so in your case, the graph will show the first value sent every second. We thought about the possibility to change step on it, but we had never proposed an option for the frequency that is less than 1 second.
That’s true, only 2 people for 3 years requested this feature, so we not gonna implement it.
Thank you for your time
But I have a question. If I’m implementing a sensor whose measurement changes fast
(an angular sensor for example) which is the best alternative to plot the data fast?? The problem of the 1 second rate it’s that I miss information of the sensor.
Blynk SuperChart minimum granularity is 1 minute anyway https://docs.blynk.cc/#widgets-displays-superchart
I’m afraid if you need something that fast maybe store it on the SD card and plot it Locally (webserver?) Or google sheets?
I am really impressed with Blynk. Visualizing time series data is central to many iot projects and sometimes data changing faster than 1Hz is of interest. Of course increasing sample rates magnifies storage and server workload - How about allow user to pass an array of samples to superchart? This would allow more rapidly changing data to be displayed without flooding server. You could limit file size to some reasonable limit by storing in a first in first out buffer of some fixed size.
Few things here.
First of all, human eye is not able to detect changes that happens faster than once per 50 ms. So your eye can capture only ~20 values per second at max.
Plotting values that fast - doesn’t give anything meaningful (we test it at the start). Sending like 10 values per second already makes reading useless within realtime graph. And we tested this many days ago.
New Blynk version will have raw data where you could be able to download the every raw value. But this would be paid feature (raw storage).