Sensors, Actuators, I/O - Computer Science and Engineering

106 Pages·2013·3.36 MB·English

Interfacing & Control
Tajana Simunic Rosing
Department of Computer Science and Engineering
University of California, San Diego.
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Hardware platform architecture
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Sensors and Actuators
Sensors

Capture physical stimulus

Convert it to electrical signal

Actuators

Create physical stimulus

Given electrical signals

Examples:

Pneumatic systems, IR, thermal, motors, MEMS
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ADC and DAC needed

Control – stability, convergence etc.

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Embedded System Hardware
Interfacing Sensors and Actuators
actuators
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Output
Output devices of embedded systems include

Displays, audio

Electro-mechanical devices: these influence the

environment through motors and other electro-
mechanical equipment. May require analog output.
Naming convention:

Digital-to-Analog (D/A)
Converters
Embedded System Hardware
Interfacing Sensors and Actuators
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Sample and Hold
VV iiss aa mmaappppiinngg ℝℝ  ℝℝ
ee
DDiiggiittaall iinnffoorrmmaattiioonn pprroocceessssiinngg;;
 DDiissccrreettee ttiimmee;; ssaammppllee aanndd hhoolldd--ddeevviicceess..
IIddeeaallllyy:: wwiiddtthh ooff cclloocckk ppuullssee -->> 00
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Analog-to-digital converters
V = 7.5V 1111 4 4
max
7.0V 1110

66..05VV 1101 )V 3 )V 3
5.5V 11100101 ( tupn 2 ( tuptu 2
445...050VVV 111000010001 i golana 1 o golan 1
a
3.5V 0111

3.0V 0110 time time
t1 t2 t3 t4 t1 t2 t3 t4
2.5V 0101

2.0V 0100 0100 1000 0110 0101 0100 1000 0110 0101

1.5V 0011 Digital output Digital input

1.0V 0010

0.5V
0001

0V
0000

analog to digital digital to analog
proportionality
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Quantization Noise
quantization noise = approx - real signal

* [http://www.beis.de/Elektronik/DeltaSigma/DeltaSigma.html]
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