Using Analog and Digital Sensors

Planning a working STEM project involves many steps.  Decisions about the input sensors require an understanding of the different ways the appropriate sensor might work.  On this activity sheet, we will discuss some possible sensors for the toy coffee machine.  The project uses a wooden structure that has no electronic sensor or control devices.  The first task was to provide a working source of DC electrity.  This was done by using a 9 volt DC battery wired to 5 volt regulators.

The first task is to find an appropriate input device.  This item becomes the sensor. 

Please read this week's Tasks and Activities.

  • The picture shows a developing project that uses a wooden coffee machine toy.  The plan will use electronic sensors and controls to simulate a real coffee machine.
  • The choice of input sensors is almost unlimited .. but could include: movement, tilt ( for safety ), light and heat.
  • Some sensors produce analog data.  This data is often represented by a voltage value between 0 and 5 volts on the Arduino boards.
  • Some sensors are purely digital devices.  They transmit bit patterns ( 0's and 1's ) with varying complexity.  Digital sensors are likely to contain complicated electronic circuits.
  • Digital sensors are steadily replacing analog sensors.  They are better integrated into digital computer control systems.

 

  
  • Here is the photograph of a analog light sensor.  It could be used to detect the opening or closing of the lid.  They are often called LDRs.
  • The sensor is a resistor that changes the input voltage with changes in light value.  This type of sensor gives an analog output.
  • This sensor is best attached to the analog input pins of an Arduino
  • The "S" pin indicates the data pin.  It can be analog or digital.
  
  • Click this image to see an enlarged image of some of the sensors that will be attached to the toy Espresso Machine.
  • Sensors are an essential part of any control system. 
  • The sensors provide the input data used to control the flow of the controlling computer program.
  

Tasks and Activities

  1. What was the first task when the toy coffee machine project began?
  2. What is the function of the connection marked "S" on the sensor circuits? ( Hint - read about the analog light sensor above )
  3. What is one of the design challenges in producing a working prototype of an Espresso machine from the wooden prototype shown above?
  4. What type of sensor will you use in your STEM project ( Hint .. does it matter if it is analog or digital? )
  5. What is one difference between an analog sensor and a digital sensor?

 

  

Don't forget to email your choices/answers to Mr. Widmer by the end of this week.  Keep a copy of that email in your Google Docs folder.