Ideas for Areas to Explore

• Add a proper finger sensor for plotting pulses: Adafruit Forums: Get a CLUE about your Pulse :-)
• Add more plotting modes:
  • min/avg/max per second/minute/hour would be useful for long-term monitoring.
  • show multiple plots on two y axis or two graphs, e.g. temperature and humidity.
• Add some supression/pause between button press and volume source to prevent the physical impact being plotted.
• Add x axis tick labels with time values and investigate the feasibility of a true oscilloscope-style output with a timebase set by the user.
• Make an altimeter and vertical speed indicator with a plot mode and an instantaneous large-font display. cf. CLUE Altimeter, published after this guide was created.
• Look at the new high performance ulab library for number crunching which could be used to post-process the sensor data.
• Enhance the code to also work on the Circuit Playground Bluefruit with the Circuit Playground TFT Gizmo LCD screen.
• Test the output to Mu particularly on the three channel plots and look at how to tailor the data sent to Mu.
• Improve the performance of plotting by replacing the slow undrawing technique with a clear screen implemented using the new, fast displayio Bitmap fill() method.

Related Projects

• Adafruit Learn: EZ Make Oven - a PyPortal oven controller with graphing usign displayio in CircuitPython.
• Adafruit Learn: Make It Plot - plotting in Mu editor.
• Adafruit Learn: Your Pulse Displayed with NeoPixels - another take on pulse representation.
• Adafruit Blog: APP UPDATE: Bluefruit Playground v1.3.0 with CLUE support (for iOS) - this has plotting capabilities.

Further Reading

• Arduino to CircuitPython: Working with Numbers
• Computerphile: Floating Point Numbers (YouTube)
• What Every Computer Scientist Should Know About Floating-Point Arithmetic by David Goldberg
• Nvidia blog: What’s the Difference Between Single-, Double-, Multi- and Mixed-Precision Computing?
• Python 3 Docs: Floating Point Arithmetic: Issues and Limitations
• Philips Medical Systems: Understanding Pulse Oximetry SpO2 Concepts
• Medical Electronics: Pulse Oximetry by Dr Neil Townsend
• Slides to accompany Chapter 8: Software Testing of Software Engineering (10th edition) by Ian Sommerville
• Visual Paradigm's UML Tutorial: Class diagrams
• pyreverse, part of pylint distribution, can generate simple class diagrams from Python code. The diagrams in this guide were created with https://app.diagrams.net/, formerly known as draw.io.