live updating scrolling linegraph from bluetooth data

I have a bluetooth device that is sending live raw data to my app. Everything as far as bluetooth is working just fine. I am trying to figure out how to plot this live data to a scrolling line graph whose width is always the width of the screen, but the height has 3 states. I have tried using the cgrect method and I can plot sample data to a graph but when I use the raw data float variable as the x coordinate, the graph is blank. I have created a timer that runs the graph plotting action every second and it does not seem to work. If someone could point me towards a tutorial or sample project, I would greatly appreciate it.

I would log the raw data values to see what the range really is.

Perhaps the values aren't what you are expecting.

I made a label to display what the actual values are and they are all between 0 and 10.

One other thought.

When the code is working with sample data and not actual data, is the only difference, in terms of the display handling, the data source?

live updating scrolling linegraph from bluetooth data
 
 
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