What is a sensor?
It its basic form a sensor reacts electrically, mechanically, chemically or in other ways to a particular stimulus in its present environment. This stimulus such as light, heat, motion, moisture pressure and a myriad of others, is the input to the sensor.
The sensor converts it to some human usable usable form that is directly available on a readable display or is used for further processing such as in any of the many types of process control or automation.
Sensors can take numerous forms, from miniature electronic chips in smartphones to large industrial monitoring systems. They are classified based on what they detect, their power source, and their output type, all of which determine their specific physical appearance and function.
Why use sensors?
Sensors are ubiquitous. Most practical microcontroller projects will involve one or more sensors at some stage. The sensor might be the star of the show where interfaced with a microcontroller and a suitable display it becomes a useful measuring device or meter. Examples abound; digital thermometers, digital tyre pressure gauges, weather monitoring stations, light and sound meters, medical observations and so.
Even where a microcontroller is used to control something; think irrigation water flow, robot control, drones, control gates and so... then just about in all cases a sensor (or two or more) will be needed.
What is this series on sensors?
This series on sensors are about those that can be easily interfaced with a microcontroller to make a measurement or inference with respect to some factor in the local environment. Since we are referencing sensors that hobbyists might use with their microcontrollers they must also be readily available and most importantly; inexpensive.
The sensors discussed are all easy to interface to the microcontroller; nothing more at most than the requirement to solder header pins to a board.
Each sensor article is strongly based around any existing (manufacturers) datasheets discovered. This, after all, is the best approach to take in understanding the characteristics of the device, especially for developing driver software and enclosing or mounting the sensor for practical use.
Articles will typically include (where applicable):
- Where the sensor comes from and what it does.
- Where the sensor is used in real life examples.
- Notes on the sensing technology used.
- Sensor specifications; physical package type and dimensions, measurement accuracy & resolution, electrical characteristics, available interfaces, etc.
- How to obtain sensor measurements with a microcontroller.
- Images, including micrographs from a digital microscope.
Final words...
At the end of each sensor article are links to MicroPython drivers for one or more different microcontroller platforms. These are freely available for anyone to use. This will continue to be a live project. Additional sensors and target microcontroller boards will continue to be added.
The drivers have all been written and tested by us at fredscave. The individual sensor pages in this series come directly from the notes taken while researching the design for the code.
This entire website is foremost meant to be a microcontroller programming resource. Readers who decide to use any of these drivers are encouraged to peruse the code for better understanding of the sensor and maybe even extend the driver class to best suit their own project.