1 EO 102 Transducers and Instrumentation.pdf

Transducers and Instrumentation

EO-102 Fundamentals of Electronics & Instrumentation Electronics & Instrumentation EO-102

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Transducers/ Sensors  Variety of Sensors/ Transducers – Digital or Analog For example: • Temperature Sensor • Humidity Sensor • Radiation Sensor • Ultrasonic Sensor • Infrared Sensor • Vibration Sensor • Global Positioning System (GPS) • Global System for Mobile Module (GSM) • Optical/ Hyper spectral Camera etc. Electronics & Instrumentation EO-102

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Sensing process Input Energy (or signal)

Transducer

Output Energy (or signal)

Fig. 1. The Sensing Process

Electronics & Instrumentation EO-102

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Definition of a transducer Transducer is any device that converts energy in one form to another energy. The majority either convert electrical energy to mechanical displacement or convert some non-electrical physical quantity, such as temperature, sound or light to an electrical signal.


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Functions of transducer 1. To sense the presence, magnitude, change in, and frequency of some measurand. 2. To provide an electrical output that, when appropriately processed and applied to readout device, gives accurate quantitative data about the measurand Measurand

Transducer

Electrical output

Excitation Measurand – refers to the quantity, property or condition which the transducer translates to an electrical signal. Electronics & Instrumentation EO-102

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Classification of transducers Transducer can be classified according to their application, based primarily on the physical quantity, property, or condition that is measured. The transducer can be categories into: A) Passive transducer: - requires an external power - output is a measure of some variation, such resistance and capacitance. E.g. : condenser microphone B) Self generating transducer: - not require an external power, and they produce analog voltage or current when stimulated by some physical form of energy. E.g. : Thermocouple Electronics & Instrumentation EO-102

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Transducer types Quantity being Measured

Input Device (Sensor)

Output Device (Actuator)

Light Dependant Resistor (LDR), Lights & Lamps, LED's & Photodiode, Phototransistor, Solar Cell Displays, Fiber Optics Thermocouple, Thermistor, Heater, Fan, Peltier Temperature Thermostat, Resistive temperature Elements detectors (RTD) Force/Pressur Strain Gauge, Pressure Switch, Load Lifts & Jacks, e Cells Electromagnetic, Vibration Potentiometer, Encoders, Motor, Solenoid, Panel Position Reflective/Slotted Opto-switch, LVDT Meters Tacho-generator, Reflective/Slotted AC and DC Motors, Stepper Speed Opto-coupler, Doppler Effect Sensors Motor, Brake Carbon Microphone, Piezo-electric Sound Bell, Buzzer, Loudspeaker Crystal Light Level


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Selecting a transducers 1. Operating range 2. Sensitivity 3. Frequency response and resonant frequency 4. Environmental compatibility 5. Minimum sensitivity measurand. 6. Accuracy 7. Usage and ruggedness 8. Electrical parameter


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Transducers to be covered • • • • • • •

Temperature transducers Resistive Position Transducer Capacitive Transducer Inductive Transducer Strain Gauge LVDT Photoelectric etc. Electronics & Instrumentation EO-102

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Temperature Transducers Temperature transducers can be divided into four main categories: 1. Resistance Temperature Detectors (RTD) 2. Thermocouples 3. Thermistor


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1) Resistance Temperature Detector (RTD) Detectors of wire resistance temperature common employ platinum, nickel or resistance wire elements, whose resistance variation with temperature has high intrinsic accuracy. They are available in many configurations and size and as shielded or open units for both immersion and surface applications. The relationship between temperature and resistance of conductors can be calculated from the equation:

R  R0 (1  T ) where R R0

α ΔT

= the resistance of the conductor at temperature t (0C) = the resistance at the reference temperature, usually 200C = the temperature coefficient of resistance = the difference between the operating and the reference temperature Electronics & Instrumentation EO-102

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2) Thermocouple

It consists of two wires of different metals are joined together at one end, a temperature difference between this end and the other end of wires produces a voltage between the wires. The magnitude of this voltage depends on the materials used for the wires and the amount of temperature difference between the joined ends and the other ends.


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Cont’d The emf of the thermocouple : E = c(T1 – T2) + k(T12 – T22) Where c and k T1 T2

= constant of the thermocouple materials = The temperature of the “hot” junction = The temperature of the “cold” or “reference” junction Electronics & Instrumentation EO-102

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Thermocouples • Two dissimilar metals induce voltage difference (few mV per 10K) – electro-thermal or Seebeck effect

• Use op-amp to process/amplify the voltage • Absolute accuracy of 1K is difficult


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3) Thermistor A thermistor is a semiconductor made by sintering mixtures of metallic oxide, such as oxides of manganese, nickel, cobalt, copper and uranium. Termistors have negative temperature coefficient (NTC). That is, their resistance decreases as their temperature rises. Types of thermistor Disc Washer Rod

Resistance 1 to 1MΩ 1 to 50kΩ high resistance


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This figure shows resistance versus temperature for a family thermistor. The resistance value marked at the bottom end of each curve is a value at 250C Note! The resistance decreases as their temperature rises-NTC


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Advantages of thermistor •

Small size and low cost

•

Fast response over narrow temperature range

•

Good sensitivity in Negative Temperature Coefficient (NTC) region

•

Cold junction compensation not required due to dependence of resistance on absolute temperature.

•

Contact and lead resistance problems not encountered due to large resistance Electronics & Instrumentation EO-102

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Limitations of thermistor

• • • •

Non linearity in resistance vs temperature characteristics Unsuitable for wide temperature range Very low excitation current to avoids self heating Need of shielded power lines, filters, etc due to high resistance


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Temperature Sensors • Bimetallic switch (electro-mechanical) – used in thermostats. Can be “creep” or “snap” action. Creep-action: coil or spiral that unwinds or coils with changing temperature

• Thermistors (thermally sensitive resistors); Platinum Resistance Thermometer (PRT), very high accuracy. Electronics & Instrumentation EO-102

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Resistive Position Transducer The principle of the resistance transducer is that the physical variable under measurement causes a resistance change in the sensing element.

A common requirement in industrial measurement and control work is to be able to sense the position of an object or distance it has moved.

R 

.

L

Potentiometer

A

R: resistance change

: density L: Length A: area Electronics & Instrumentation EO-102

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Cont’d

FIG 1 (a)

FIG 1 (b)

Figure shows the construction of a displacement transducer uses a resistance element with a sliding contact or wiper linked to the object being monitored. The resistance between the slider and one end of the resistance element depends on the position of the object. The output voltage depends on the wiper position and therefore is a function of the shaft position Electronics & Instrumentation EO-102

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Consider Fig 1 (b), if the circuit is unloaded, the output voltage V 0 is a certain fraction of VT, depending on the position of the wiper:

V0 R2  VT R1  R2 This equation shows that the output voltage is directly proportional to the position of the wiper, if the resistance of the transducer is distributed uniformly along the length of travel of the wiper

EXAMPLE 1 A displacement transducer with a shaft stroke of 4 in. is used in the circuit of figure 1 (b). R1 +R2 is 1000 Ω and VT = 4 V. The wiper is 1.5 in from B. Find V0?


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Positional Sensors: potentiometer Can be Linear or Rotational

Processing circuit


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Positional Sensors: Rotary Encoders • Incremental and absolute types • Incremental encoder needs a counter, loses absolute position between power glitches, must be re-homed • Absolute encoders common in CD/DVD drives


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Capacitive Transducer The capacitance of a parallel plate capacitor is given by

kA 0 C ( Farads) d where k A εo d

= dielectric constant = the area of the plate, in m2 = 8.854 x 10-12 F/m = the plate placing in m


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Cont’d Forms of Capacitance Transducers

Rotary plate capacitor

Rectilinear Capacitance Transducer Thin diaphragm


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Cont’d

Rotary plate capacitor: The capacitance of this unit proportional to the amount of the fixed plate that is covered, that shaded by moving plate. This type of transducer will give sign proportional to curvilinear displacement or angular velocity.


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Cont’d Rectilinear capacitance transducer: It consists of a fixed cylinder and a moving cylinder. These pieces are configured so the moving piece fits inside the fixed piece but insulated from it.


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Cont’d Thin diaphragm: A transducer that varies the spacing between surfaces. The dielectric is either air or vacuum. Often used as Capacitance microphones.


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Cont’d

Advantages: 1. Has excellent frequency response 2. Can measure both static and dynamic phenomena. Disadvantages: 1. Sensitivity to temperature variations 2. the possibility of erratic or distortion signals owing to long lead length Applications: 1. As frequency modulator in RF oscillator 2. In capacitance microphone 3. Use the capacitance transducer in an ac bridge circuit


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Inductive Transducer Inductive transducers may be either of the self generating or passive type. The self generating type utilises the basic electrical generator principle, i.e, a motion between a conductor and magnetic field induces a voltage in the conductor (generator action). This relative motion between the field and the conductor is supplied by changes in the measurand. An inductive electromechanical transducer is a device that converts physical motion (position change) into a change in inductance. Transducers of variable inductance type work upon one of the following principles: 1. Variation of self inductance 2. Variation of mutual inductance Electronics & Instrumentation EO-102

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Cont.. Inductive transducers are mainly used for the measurement of displacement. The displacement to be measured is arranged to cause variation in any of three variables: 1. Number of turns 2. Geometric configuration 3. Permeability of the magnetic material or magnetic circuits


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Positional Sensors: Inductive Proximity Switch • Detects the presence of metallic objects (non-contact) via changing inductance • Sensor has 4 main parts: field producing Oscillator via a Coil; Detection Circuit which detects change in the field; and Output Circuit generating a signal (NO or NC) Used in traffic lights (inductive loop buried under the road). Sense objects in dirty environment. Does not work for non-metallic objects. Omni-directional.


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Strain Gauge The strain gauge is an example of a passive transducer that uses electric resistance variation in wires to sense the strain produced by a force on wires. It is a very versatile detector and transducer for measuring weight, pressure, mechanical force, or displacement. The construction of a bonded strain gauge (see figure) shows a fine wire element looped back and forth on a mounting plate, which is usually cemented to the member undergoing stress. A tensile stress tends to elongate the wire and thereby increase its length and decrease its cross-sectional area. Electronics & Instrumentation EO-102

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The combined effect is an increase in resistance:

R Where,

L A

ρ: the specific resistance of the conductor material in ohm meters L : length of conductor (meters) A : area of conductor (m2) As consequence of strain, 2 physical qualities are particular interest: 1) The change in gauge resistance 2) The change in length The relationship between these two variables called gauge factor, K, is expressed mathematically as


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R / R K L / L Where

K= the gauge factor R=the initial resistance in ohms (without strain) ∆R= the change in initial resistance in ohms L= the initial length in meters (without strain) ∆L=the change in initial length in meters ∆L/L same unit with G, therefore

R / R K G Electronics & Instrumentation EO-102

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From Hooke theory, stress, S, is defined as internal force/area.

F S A Where S= the stress in kilograms per square meter F= the force in kilograms A= area in square meters Then the modulus of elasticity of material E or called Young’s modulus (Hooke’s Law) is written as:

S E G

Where, E= Young modules in kg per square meter S= the stress in kilograms per square meter G= the strain (no units)


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Metallic strain gauge – formed from thin resistance wire or etched from thin sheets of metal foil. Wire gauge (small) – to minimum leakage – for high T applications Semiconductor strain gauge – high output transducers as load cells Strain gauge is generally used as one arm of bridge


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Positional Sensors: LVDT Linear Variable Differential Transformer


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LINEAR VARIABLE DIFFERENTIAL TRANSFORMER (LVDT) It consists basically of a primary winding and two secondary windings, wound over a hollow tube and positioned so the primary winding is between two secondaries. In figure shows the construction of the LVDT.

An iron core slides within the tube and therefore affects the magnet coupling between the primary and the two secondaries. When the core is in the centre, voltage induced in the two secondaries is equal. When the core is moved in one direction from centre, the voltage induced in one winding is increased and that in the other is decreased. Movement in the opposite direction reverses this effect Electronics & Instrumentation EO-102

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Cont..


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Cont..


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Motion sensors/transducers • Switches, solenoids, relays, motors, etc. • Motors • DC • Brushed/brushless Stepper motor • Servo • Stepper motors • AC

Brushed motor – permanent magnets on armature, rotor acts as electromagnet Electronics & Instrumentation EO-102 Brushless motor – permanent magnet on the rotor, electromagnets on armature are switched

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Light sensors: photoconductive cells • Light dependent resistor (LDR) cell


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Light level sensitive switch


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Photo-junction devices phototransistor photodiode


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• What’s Photoelectric Effect? -is the emission of electrons from matter upon the absorption of electromagnetic radiation, such as ultraviolet radiation or x-rays.-refers to the emission, or ejection, of electrons from the surface of, generally, a metal in response to incident light.


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Photoelectric Transducer Can be categorized as: photoemissive, photoconductive, or photovoltaic.

No. Types

Characteristics

1.

Photoemmisive

radiation falling into a cathode causes electrons to be emitted from cathode surface.

2.

Photoconductive

the resistance of a material is change when it’s illuminated.

3.

Photovoltaic

Generate an output voltage proportional to radiation intensity Electronics & Instrumentation EO-102

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• Examples of Photoelectric Transducer • (i) The Photomultiplier Tube • (ii) Photoconductive Cells OR Photocells the electrical resistance of the materials varies with the amount of light striking. • (iii) The Photovoltaic Cell or solar cell - produce an electrical current when connected to the load.


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Photovoltaic Solar Cells • Can convert about 20% of light power into electricity • Voltage is low (diode drop, ~0.6V)

Solar power is 1.4kW/m^2


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Photomultiplier tubes (PMT) • Most sensitive of light sensors (can detect individual photons) • Acts as a current source

electrons


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Piezo transducers • Detect motion (high and low frequency) • Sound (lab this week), pressure, fast motion • Cheap, reliable but has a very limited range of motion


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Piezoelectric transducers are based on the property of accumulating charges if stressed (direct effect)and to strain in case of an electric signal is applied across their electrodes (inverse effect) Piezoelectricity is due to asymmetries in the crystallographic structure.


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The Curie point is about 130°C. Above 130°C, a nonpiezoelectric cubic phase is stable, where the center of positive charge (Ba2+ and Ti4+) coincides with the center of the negative charge (O2–) (Figure a). When cooled below the Curie point, a tetragonal structure (shown in Figure b) develops where the center of positive charge is displaced relative to the O2–ions, leading to the formation of electric dipoles. Electronics & Instrumentation EO-102

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Naturally occurring Piezoelectric Material • Quartz • Berlinite (AlPO4), a rare phosphate mineral that is structurally identical to quartz • Sucrose (table sugar) • Rochelle salt

• Topaz • Tourmaline-group minerals • Lead Titanate (PbTiO3)


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Advantages •High stiffness, to measure force. •High resonant frequency (up to 500 kHz) •Stability, reproducibility and linearity •Large operating temperature range •Low sensitivity to external magnetic field. Drawbacks •Curie Temperature, Tc •Resonant behaviour •High output impedance •Cannot be used to detect static quantities Electronics & Instrumentation EO-102

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Sound transducers microphone

speaker

• Note: voice coil can also be used to generate fast motion Electronics & Instrumentation EO-102

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Where would you interface these sensors?  Require suitable sensor nodes For example: • Single Board Microcontrollers • Arduino Uno • Single Board Computers • Raspberry Pi • Beaglebone Black


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ATmega328 The ATmega328 is a single chip micro-

controller

created

by

Atmel

and

belongs to the megaAVR series. The Atmel 8-bit AVR RISC-based microcontroller combines 32 KB ISP flash memory with read-while-write capabilities, 1 KB EEPROM, 2 KB SRAM, 23 general purpose I/O lines, 32 general purpose working registers, three flexible timer/ counters with compare modes, internal and external interrupts, serial programmable USART, a byte-oriented 2-wire serial interface, SPI serial port, 6-channel 10-bit A/D converter (8channels in TQFP and QFN/MLF packages), programmable watchdog timer with internal oscillator, and five software selectable power saving modes. The device operates between 1.8-5.5 volts. The device achieves throughputs approaching 1 MIPS.


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Arduino • A free development system based on Atmega328.


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What is Arduino • Open Source Hardware, you can make your own board, or buy one. • Cheap, easily available. • Open Source Software. • Very widespread, many projects openly available. • Extra HW (shields) available.


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Arduino Uno


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Arduino IDE


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Arduino Language • • • • • • • •

C like syntax, but simplified Abstracts the pin naming to numbers Trades efficience for ease of use Easy to learn, yet powerful Lots of example code Easy to reuse C-code from other projects Libraries can be written in C++ Lots of libraries available


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Simple Arduino Code(Blink LED) int ledPin = 13; // LED connected to digital pin 13

// The setup() method runs once, when the sketch starts void setup() {

// initialize the digital pin as an output: pinMode(ledPin, OUTPUT); }

// the loop() method runs over and over again,

// as long as the Arduino has powervoid loop() { digitalWrite(ledPin, HIGH); // set the LED on delay(500); // wait for half a second

digitalWrite(ledPin, LOW); // set the LED off delay(500); // wait for half a second }


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Introduction to Raspberry Pi (RPi)


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What is Raspberry Pi • Created by Raspberry Pi Foundation • The Raspberry Pi is a credit-card sized computer that plugs into your TV and a keyboard. • Available in two revisions (Model-A and Model-B) • It has a powerful processing unit (BCM2835 ARM11 RISC) • Graphic processing capabilities (GPU@250MHz) • Has ported Open source OSs specially developed for ARM11 like Raspbian, Pidora, etc. Raspberry+debian = Raspbian,Fedora Remix+Raspberry = Pidora Electronics & Instrumentation EO-102

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Why Raspberry pi? • Faster on-Board processing (When spontaneous response is required). • Includes Audio-Video processing capabilities. • Extended Peripheral devices support (like Keyboard, Mouse, USB-stick etc.) • Networkable board (via Ethernet Cable) • Camera support (CSI) • Less power consumption (5V adapter)


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Model A Model B Rs.1900 Rs.2400 700 MHz ARM1176JZF-S core (ARM11 family) Broadcom VideoCore IV, OpenGL ES 2.0, MPEG-2 and VC1, 1080p 30 h.264/MPEG-4 AVC

Raspberry Pi Model-A and B Price CPU:

GPU: Memory (SDRAM): USB 2.0 ports: Video outputs:

256 MB (shared with GPU)

512 MB (shared with GPU)

1 2 Composite RCA, HDMI, raw LCD Panels via DSI 14 HDMI resolutions from 640×350 to 1920×1200 HDMI, 3.5 mm jack (stereo analog) SD / MMC / SDIO card slot

Audio outputs: Onboard storage: Onboard None 10/100 Ethernet network: Power ratings: 300 mA (1.5 W) 700 mA (3.5 W) Size and Weight 85.60 mm × 53.98 mm, 45 g Operating Debian GNU/Linux, Raspbian OS, Fedora, Arch Linux ARM, systems: RISC OS, FreeBSD, Plan 9 Electronics & Instrumentation EO-102

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Raspberry Pi (Short Map) Audio Video

USB

GPIO

Ethernet

DSI

CSI SD

HDMI Power

CPU/GPU Electronics & Instrumentation EO-102

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Ref:

http://pi.gadgetoid.com/pinout/pin6_ground http://makezine.com/projects/tutorial-raspberry-pi-gpio-pins-and-python/ Electronics & Instrumentation EO-102

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Set up your Raspberry Pi • • • • • • •

SD card (Minimum size 4Gb) HDMI to HDMI / DVI lead RCA video lead (if you are not using the HDMI output) Keyboard and mouse (USB 2.0) Ethernet network cable (optional) Power adapter (micro USB power 700mA at 5V) Audio lead (If you are not using HDMI)

HDMI connector

HDMI to DVI lead

RCA composite video connector Electronics & Instrumentation EO-102

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Set up your Raspberry Pi


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Serial between Arduino-RPi • Data Received on RPi using simple Python programs accessing USB serial • Data can be immediately processed and send back to arduino for further routing over network


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LM335 PRECISION TEMPERATURE SENSOR The LM335 are precision temperature sensors which can be easily calibrated. Wide range, low power temperature sensor outputs an analog voltage that is proportional to the ambient temperature •1°C Initial Accuracy Available •Operates from 400 μA to 5 mA •Less than 1Ω Dynamic Impedance •200 °C overrange •Time stability (Tcase = +125°C)=0.2 °C/kh Electronics & Instrumentation EO-102

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Interfacing with Arduino


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Interfacing with Raspberry Pi Required parts • • • • •

Raspberry Pi MCP3008 8 channel ADC Light dependent resistor (LDR) TMP36 temperature sensor 10 Kohm resistor


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MCP 3008 The MCP3008 is a 10bit 8-channel Analogue-to-digital converter (ADC). The following list shows how the MCP3008 can be connected. It requires 4 GPIO pins on the Pi P1 Header. VDD 3.3V VREF 3.3V AGND GROUND CLK GPIO11 (P1-23) DOUT GPIO9 (P1-21) DIN GPIO10 (P1-19) CS GPIO8 (P1-24) DGND GROUND Electronics & Instrumentation EO-102

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Reading The Data Using a Python Script #!/usr/bin/python import spidev temp = ((data * 330)/float(1023))-50 import time temp = round(temp,places) import os return temp # Open SPI bus # Define sensor channels light_channel = 0 spi = spidev.SpiDev() temp_channel = 1 spi.open(0,0) # Define delay between readings # Function to read SPI data from MCP3008 chip delay = 5 # Channel must be an integer 0-7 while True: def ReadChannel(channel): # Read the light sensor data light_level = ReadChannel(light_channel) adc = spi.xfer2([1,(8+channel)<<4,0]) light_volts = ConvertVolts(light_level,2) data = ((adc[1]&3) << 8) + adc[2] # Read the temperature sensor data return data temp_level = ReadChannel(temp_channel) # Function to convert data to voltage level, temp_volts = ConvertVolts(temp_level,2) # rounded to specified number of decimal places. temp = ConvertTemp(temp_level,2) # Print out results def ConvertVolts(data,places): print "--------------------------------------------" volts = (data * 3.3) / float(1023) print("Light: {} ({}V)".format(light_level,light_volts)) volts = round(volts,places) print("Temp : {} ({}V) {} deg return volts C".format(temp_level,temp_volts,temp)) # Function to calculate temperature from # Wait before repeating loop time.sleep(delay) # TMP36 data, rounded to specified # number of decimal places. def ConvertTemp(data,places): Electronics & Instrumentation EO-102

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MQ-6 LPG Sensor They are used in gas leakage detecting equipment in family and industry, are suitable for detecting of LPG, iso-butane, propane, LNG, avoid the noise of alcohol and cooking fumes and cigarette smoke.

FEATURES • MQ-6: High sensitive to LPG, Propane, Butane. • Small sensitivity to alcohol, smoke • Fast response • Stable and long life • Simple drive circuit


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Interfacing with Arduino int sensorValue; void setup() { Serial.begin(9600); port to 9600 }

// sets the serial

void loop() { sensorValue = analogRead(0); // read analog input pin 0 Serial.println(sensorValue, DEC); // prints the value read delay(100); // wait 100ms for next reading } Electronics & Instrumentation EO-102

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MQ-7 Gas sensor •

This is a simple-to-use Carbon Monoxide (CO) sensor, suitable for sensing CO concentrations in the air. The MQ-7 can detect CO-gas concentrations anywhere from 20 to 2000ppm.This sensor has a high sensitivity and fast response time. The sensor’s output is an analog resistance.

• • •

FEATURES High sensitivity to carbon monoxide Stable and long life Heating consumption About 350mW

• • •

APPLICATION They are used in gas detecting equipment for carbon monoxide(CO) in family and industry or car.


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Interfacing with Arduino • int sensorValue; • void setup() • { • Serial.begin(9600); port to 9600 • }

// sets the serial

• void loop() • { • sensorValue = analogRead(0); // read analog input pin 0 • Serial.println(sensorValue, DEC); // prints the value read • delay(100); // wait 100ms for next reading • } Electronics & Instrumentation EO-102

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Electrat (condensor) microphone • •

DESCRIPTION An electret microphone is a type of condenser microphone, which eliminates the need for a polarizing power supply by using a permanently charged material.

APPLICATIONS 1.Telephones 2.Handheld devices 3.Recording devices 4.2-way communications 5.Audio/visual equipment 6.Flow detectors 7.GPS systems


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Interfacing with Arduino

void setup() { Serial.begin(9600); } void loop() { Serial.println(analogRead(0)); delay(300); }


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PIR sensor PIR sensors allow you to sense motion, almost always used to detect whether a human has moved in or out of the sensors range. PIRs are basically made of a pyroelectric sensor which can detect levels of infrared radiation.

FEATURES 1. Operating voltage: 4.5V to 20V DC 2. Static power consumption: 65 micro-amps 3. Output Logic level : High-3.3V, Low-0V 4. Delay Time: adjustable (5-200S +-3%) 5. Blocked Time: 2.5 Seconds Default 6. Trigger Jumper: L No Repeat, H Repeated Trigger(Default) 7. Sensing range: <1400 , 3-7 meters(Adjustable) 8. Operating temperature: -20 -+800 C


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Interfacing with Arduino void setup() { Serial.begin(9600);} Serial.println("Warming up..."); delay(20000); }

void loop() { Serial.print("IN2 = "); Serial.println(digitalRead(2), DEC); delay(200); }


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Infrared transmitter and reciever •

Infrared proximity sensor has an analog output that varies from 2.8V at 15cm to 0.4V at 150cm with a supply voltage between 4.5 and 5.5VDC.

• •

■Features 1. Distance measuring range : 20 to 150 cm 2. Analog output type 3. Package size : 29.5×13×21.6 mm 4. Consumption current : Typ. 33 mA 5. Supply voltage : 4.5 to 5.5 V

• • • • • • • • • •

■Applications 1. Touch-less switch (Sanitary equipment, Control of illumination, etc. ) 2. Sensor for energy saving (ATM, Copier, Vending machine, Laptop computer, LCD monitor) Electronics & Instrumentation EO-102

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Interfacing with Arduino const int x;

void setup() { Serial.begin(9600);}

void loop() { x = analogRead(2); Serial.println(x); }


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DHT11 Humidity sensor DHT11 digital temperature and humidity sensor is a composite Sensor contains a calibrated digital signal output of the temperature and humidity. 2、Applications HVAC, dehumidifier, testing and inspection equipment, consumer goods, automotive, automatic control, data loggers, weather stations, home appliances, humidity regulator, medical and other humidity measurement and control. 3、Features Low cost, long-term stability, relative humidity and temperature measurement, excellent quality, fast response, strong anti-interference ability, long distance signal transmission, digital signal output, and precise calibration. Electronics & Instrumentation EO-102

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Interfacing with Arduino int potpin=0; int ledpin=12; int potval=0; Void setup() { pinMode(ledpin,OUTPUT); } Void loop(){ Potval= analogRead(potpin); digitalWrite(ledpin,HIGH); Delay(potval); digitalWrite(ledpin,LOW); Delay(potval); }


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Accelerometer sensor The ADXL335 is a small, thin, low power, complete 3-axis accel-erometer with signal conditioned voltage outputs. The product measures acceleration with a minimum full-scale range of ±3 g FEATURES Small and thin 4 mm × 4 mm × 1.45 mm LFCSP package Wide supply voltage range: 2.4 V to 5.25 V Low power: 350 µA at VS = 2.4 V (typ) Good sensitivity accuracy X-axis and Y-axis aligned to within 0.1° (typ) Single-supply operation 10,000 g shock survival APPLICATIONS Cost-sensitive motion- and tilt-sensing applications Smart hand-held devices Sports and health-related devices PC security and PC peripherals


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Interfacing with Arduino const int groundpin = 18; // analog input pin 4 const int powerpin = 19; // analog input pin 5 const int xpin = A3; // x-axis of the accl. const int ypin = A2; // y-axis const int zpin = A1; // z-axis (only on 3-axis void setup() { Serial.begin(9600); pinMode(groundpin, OUTPUT); pinMode(powerpin, OUTPUT); digitalWrite(groundpin, LOW); digitalWrite(powerpin, HIGH); } void loop() { Serial.print(analogRead(xpin)); Serial.print("\t"); Serial.print(analogRead(ypin)); Serial.print("\t"); Serial.print(analogRead(zpin)); Serial.println(); Electronics & Instrumentation EO-102 102 delay(100);

1 EO 102 Transducers and Instrumentation.pdf

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