Smart Objects Flashcards
In what ways can identity be recorded and conveyed?
Machine readable characters
Barcodes
Magnetic strips
Biometrics
What does RFID stand for?
Radio frequency identification
Briefly describe how RFID works
RFID is non-contact and non-visual
Twin coils with an AC source induce a voltage at the secondary coil. The load resistor defines the current flowing through the secondary coil which induces the voltage across the primary. Using the voltage on the primary the load can be estimated.
In RIFD the reader corresponds to the primary and the tag to the secondary. Load modulation allows messages to be sent from the tag. Identity information is stored in a memory chip on the tag.
Low frequency tends to be passive, high frequency tends to be active
What are the categorisations of sensing?
Active/passive
Invasive/non-invasive
Contact/non-contact
Absolute/relative
What are some types of actuation?
Mechanical Electrical Electromagnetic Electromechanical Hydraulics/ pneumatic
What are some trends of ubiquitous smart objects?
Decreasing size
Decreasing power consumption
Increasing processing capabilities
Improving communications capabilities
What are the advantages of sensor actuator networks?
Flexible
Easily scaled
Low installation and maintenance cost
Can easily adapt to topology changes
What are the disadvantages of sensor actuator networks?
Lower transmission speeds
Greater environmental interference
Greater security risks
What is a scratch drive actuator? How does it work?
A microelectromechanical system device that converts electrical energy into one-dimensional motion
L-shaped actuator that sits on top of a substrate, separated by a dielectric. Voltage applied which pulls body of actuator down, bending the L and pushing the ‘arm’ forwards. Voltage removed, returns to original shape and drags itself along.
What are MEMS actuators?
devices that convert electrical energy to mechanical motion
