Project: Temperature Sensor
Project purpose:
Measuring changes in temperature by a sensor, likewise deployed applications of operational amplifiers seen during the course such as a digital analog converter.
Theoretical Introduction
♥ LM35
The LM35 is a temperature sensor with a calibrated accuracy of 1 ° C and a range that extends from -55 º to +150 º C.
The LM35 is a temperature sensor with a calibrated accuracy of 1 ° C and a range that extends from -55 º to +150 º C.
The sensor is available in different encapsulated but the most common is to-92 in the same way that a typical transistor with 3 legs, two of them to feed and the third gives us a voltage proportional to the temperature measured by the device. LM35 with the pins on the table for us and the letters we have encapsulated upward from left to right the pins are: VCC - Vout - GND.
Its main characteristics are:
Accuracy of ~ 1.5 ° C (worst case), 0.5 º C to 25 ° C. GuaranteedNon-linearity of ~ 0.5 ° C (worst case).
Low supply current (60uA).
Wide range of operation (from -55 ° to + 150 º C).
Low cost.
Low output impedance.
The output is linear and equal to 10mV / ° C thus:
+1500 MV = 150 ° C
+250 MV = 25 ° C
-550mV = -55 ° C
Performance: To get a thermometer all we need is a voltmeter and well calibrated at the correct scale to show us the voltage equivalent of temperature. The LM35 operates in the power range between 4 and 30 volts.
We can connect to an analog / digital converter and digital measurement treat, store or process with a micro controller or similar.
©Operational Amplifier
An operational amplifier (commonly abbreviated AO, op-amp or OPAM), is an electronic circuit (usually presented as integrated circuit) having two inputs and one output. The output is the difference of the two inputs multiplied by a factor (G) (gain):
Vout = G • (V + - V-)
The symbol of an amplifier is shown in the figure below:
An operational amplifier (commonly abbreviated AO, op-amp or OPAM), is an electronic circuit (usually presented as integrated circuit) having two inputs and one output. The output is the difference of the two inputs multiplied by a factor (G) (gain):
Vout = G • (V + - V-)
The symbol of an amplifier is shown in the figure below:
The terminals are:
V +: non-inverting input
V-: inverting input
VOUT: Output
VS +: positive power
VS-: negative power
♥ GAL22V10
GAL (Generic Array Logic), Spanish Generic Array Logic, are a type of integrated circuit, a trademark of Lattice Semiconductor, which has been designed with the purpose of replacing most of the PAL, while maintaining compatibility of its terminals.
It uses an EEPROM memory array in place so that you can program several times.
A GAL in its basic form is a PLD with a programmable AND array, OR array logic of fixed and programmable output through a macrocell. This structure allows to implement any logic function as sum of products with a number of defined terms.
V +: non-inverting input
V-: inverting input
VOUT: Output
VS +: positive power
VS-: negative power
♥ GAL22V10
GAL (Generic Array Logic), Spanish Generic Array Logic, are a type of integrated circuit, a trademark of Lattice Semiconductor, which has been designed with the purpose of replacing most of the PAL, while maintaining compatibility of its terminals.
It uses an EEPROM memory array in place so that you can program several times.
A GAL in its basic form is a PLD with a programmable AND array, OR array logic of fixed and programmable output through a macrocell. This structure allows to implement any logic function as sum of products with a number of defined terms.
Not reprogrammable PLDs in the synthesis of logic equations is done by burning fuse at each point of intersection of the input pins to the gates. In the case of a GAL is basically the same idea but instead of being formed by a network of conductors arranged in rows and columns in which at each point of intersection is a fuse, the fuse is replaced by an electrically erasable CMOS cell (EECMA). By programming to enable or disable each cell EECMA and can apply any combination of input variables or their complements, to an AND gate to generate any desired product operation. An active cell junction connects its corresponding row and column, and a cell switched off the intersection. The cells can be electrically erased and reprogrammed.
OperationA GAL can implement any expression in sum of products with a number of defined variables, for example, this diagram shows the basic structure of a GAL for two inputs and one output.
The programming process is to enable or disable each cell E2CMOS with the aim of applying the right combination of variables to each gate and get the sum of products
The output of AND gates are introduced in the output logic macrocell containing OLMC OR gates and programmable logic.
©Electrical resistance
The electrical resistance of an object is a measure of its opposition to the passage of current.
Discovered by Georg Ohm in 1827, the electrical resistance has a conceptual similarity to friction in mechanical physics. The unit of resistance in the International System of Units is the ohm (Ω).To measure in practice there are various methods, among which is the use of an ohmmeter. In addition, their mutual quantity is the conductance measured in Siemens.
For a lot of materials and conditions, the electrical resistance depends on the electric current passing through an object and the terminal voltage of this. This means that, given a temperature and material, the resistance is a value that will remain constant. In addition, according to Ohm's law the resistance of a material can be defined as the ratio of voltage and current, as follows:
Discovered by Georg Ohm in 1827, the electrical resistance has a conceptual similarity to friction in mechanical physics. The unit of resistance in the International System of Units is the ohm (Ω).To measure in practice there are various methods, among which is the use of an ohmmeter. In addition, their mutual quantity is the conductance measured in Siemens.
For a lot of materials and conditions, the electrical resistance depends on the electric current passing through an object and the terminal voltage of this. This means that, given a temperature and material, the resistance is a value that will remain constant. In addition, according to Ohm's law the resistance of a material can be defined as the ratio of voltage and current, as follows:
R=V/I
Depending on the magnitude of this measure, the materials can be classified as conductors, insulators and semiconductors.There are also some materials that, under certain conditions of temperature, a phenomenon called superconductivity appears, in which the resistance value is practically zero.
Depending on the magnitude of this measure, the materials can be classified as conductors, insulators and semiconductors.There are also some materials that, under certain conditions of temperature, a phenomenon called superconductivity appears, in which the resistance value is practically zero.
© Capacitors
A capacitor or capacitor is a device that stores electrical energy, is a passive component. It consists of a pair of conductive surfaces in a position to influence total (that is, that all electric field lines will start from a stop to the other), usually in the form of tables, fields or sheets, separated by a material dielectric (this being used in a capacitor to reduce the electric field as it acts as an insulator) or by vacuum, which, subject to a potential difference (pd) acquire a certain electric charge, one positive and negative plates in the other (being zero total charge stored).
Operation
The charge stored in one of the plates is proportional to the difference in potential between the plate and the other being the constant of proportionality called capacity or capacitance. In the International System of Units is measured in farads (F), with 1 farad capacitor capacity in which, under their armor to a ddp 1 volt, they acquire an electric charge of 1culombio.
© 7-segment display
It is a way of representing numbers in electronic equipment. It is composed of seven segments that can be turned on or off individually. Each segment is shaped like a small line.
The 7-segment display and 7-segment display is a component that is used for the representation of numbers in many electronic devices largely because of its simplicity. Although outwardly the form differs considerably from an LED (light emitting diodes) typical, internally consist of a series of LEDs with certain internal connections, strategically placed so that it forms a number 8.
Each of the segments that make up the display are called a, b, c, d, e, fygy are assembled so as to allow each segment separately activated form getting any numeric digit. Below are some examples:
The charge stored in one of the plates is proportional to the difference in potential between the plate and the other being the constant of proportionality called capacity or capacitance. In the International System of Units is measured in farads (F), with 1 farad capacitor capacity in which, under their armor to a ddp 1 volt, they acquire an electric charge of 1culombio.
© 7-segment display
It is a way of representing numbers in electronic equipment. It is composed of seven segments that can be turned on or off individually. Each segment is shaped like a small line.
The 7-segment display and 7-segment display is a component that is used for the representation of numbers in many electronic devices largely because of its simplicity. Although outwardly the form differs considerably from an LED (light emitting diodes) typical, internally consist of a series of LEDs with certain internal connections, strategically placed so that it forms a number 8.
Each of the segments that make up the display are called a, b, c, d, e, fygy are assembled so as to allow each segment separately activated form getting any numeric digit. Below are some examples:
If you turn on or turn on all segments form the number "8".
If the segments are activated only: "a, b, c, d, e, f," forms the number "0".
If the segments are activated only: "a, b, g, e, d," forms the number "2".
If you are only activated segments: "b, c, f, g," forms the number "4".
Often appears eighth segment called pd (Decimal point).
If the segments are activated only: "a, b, c, d, e, f," forms the number "0".
If the segments are activated only: "a, b, g, e, d," forms the number "2".
If you are only activated segments: "b, c, f, g," forms the number "4".
Often appears eighth segment called pd (Decimal point).
The LEDs operate at low voltage and low power, therefore, be excited directly with logic gates. Usually you use an encoder (in our case decimal / BCD) that activating a single input pins of the encoder enable the corresponding outputs showing the desired number. Remember also that there are 16-segment alphanumeric display and even an array of 7 * 5 (35 bits).
They are of two types: common anode and common cathode.
In common anode type, all the anodes of the LEDs or segments are connected internally to a common pin should be connected to positive potential (level "1"). The lighting of each individual segment is performed by applying a negative potential (level "0") for the corresponding pin through a resistor that limits the current flow.
In common cathode type, all the cathodes of the LEDs or segments are connected internally to a common pin should be connected to negative potential (level "0"). The lighting of each individual segment is performed by applying positive potential (level "1") corresponding to the pin through a resistor that limits the current flow.
Segments can be of various colors, although the most commonly used display is red, for ease of viewing.
There are also 14-segment alphanumeric displays that can represent both letters and numbers. The 14-segment display had limited success and there is only marginally due to competition from 5x7 dot matrix.
Although today these displays seem old or obsolete. It is now common to use colorful graphic displays, even with color capability at low cost. However, the 7-segment display is still an excellent option in certain situations where greater power is required lighting and working in hostile areas, where the displays could be affected by adverse environmental conditions. Has not been created yet another signaling device characteristics such as this in: Good lighting power, clarity, easy implementation, low cost and robustness.
They are of two types: common anode and common cathode.
In common anode type, all the anodes of the LEDs or segments are connected internally to a common pin should be connected to positive potential (level "1"). The lighting of each individual segment is performed by applying a negative potential (level "0") for the corresponding pin through a resistor that limits the current flow.
In common cathode type, all the cathodes of the LEDs or segments are connected internally to a common pin should be connected to negative potential (level "0"). The lighting of each individual segment is performed by applying positive potential (level "1") corresponding to the pin through a resistor that limits the current flow.
Segments can be of various colors, although the most commonly used display is red, for ease of viewing.
There are also 14-segment alphanumeric displays that can represent both letters and numbers. The 14-segment display had limited success and there is only marginally due to competition from 5x7 dot matrix.
Although today these displays seem old or obsolete. It is now common to use colorful graphic displays, even with color capability at low cost. However, the 7-segment display is still an excellent option in certain situations where greater power is required lighting and working in hostile areas, where the displays could be affected by adverse environmental conditions. Has not been created yet another signaling device characteristics such as this in: Good lighting power, clarity, easy implementation, low cost and robustness.
ü Simulations
The simulations do not apply to this project because there is no LM35 (temperature sensor) in the software and no way to simulate the signal to reach the ADC 0804 for them to send the signal value to GAL22V10 and these themselves to the 7-segment display's.
Project Diagram
The first stage of the circuit begins with the LM35 temperaturesensor which sends a certain amount of voltage for each degreecentigrade of records, so it sends the signal is linear.
This signal is received by the ADC (Analog Digital Converter)which by means of the internal connection of operational amplifiers and other elements, which transforms the analog signalinto a digital input, ie taking logical value "1 "and" 0 ".
Once the new signal, the two PLD's connected to the circuitwhose function is to decode it to be displayed in two display `scommon anode will be representing the temperature recorded by the LM35 in a decimal value in degrees Celsius.
This signal is received by the ADC (Analog Digital Converter)which by means of the internal connection of operational amplifiers and other elements, which transforms the analog signalinto a digital input, ie taking logical value "1 "and" 0 ".
Once the new signal, the two PLD's connected to the circuitwhose function is to decode it to be displayed in two display `scommon anode will be representing the temperature recorded by the LM35 in a decimal value in degrees Celsius.
ü Ishikawa diagram
ü | |||
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