10 Introduction to MECH 217
This book provides most of the materials and background needed to complete the Queen’s course MECH 217: Measurement for Mechatronics, following the sequence laid out for the course on onQ. It is intended as a supplement to a fully comprehensive text like Figliola & Beasley: Theory and Design for Mechanical Measurements, 6th Edition from Wiley and students will need to display some lifelong learning skills to gather information from multiple sources including manufacturer’s sites on the web.
Some of the files referred to in this book can be obtained as a GitHub archive at https://github.com/sellensr/RWS-Notes to install, view, and run on your own computer. This is particularly useful for Jupyter Notebooks and Arduino sketches that rely on having all the component files in the right folders to avoid errors. Other proprietary information is best gathered from the latest editions of manufacturer’s data sheets, often available through a web search by part number.
Why Mechanical Engineers Measure
The reasons we make measurements depend on the activities we are supporting (video 12:57). In MECH 217 we will focus on making electronic measurements of mechanical quantities using microcontrollers.
Time Series Data
Just about every system we care about changes with time, so we need to think of data as time series: (video 2:28)
Analog and Digital Signals
Analog signals vary continuously in voltage. The UNO operates in the TTL range anywhere between 0 and 5 volts DC, while newer microcontrollers use 0 and 3.3 volts DC. Digital signals are either on or off, either 1 or 0, 3.3 volts or 0 volts ( 5 volts or 0 volts for the UNO). (video 1:25)
Focus on Coding in the Arduino IDE
The main focus in MECH 217 will be on coding in the Arduino IDE to make measurements from sensors and respond to those measurements. We will focus on simple resistive circuits and digital sensors as sources of those measurements.