This that are needed for this unit include

This report paper analyses a small sensor unit and analogy amplifier which is positioned at the when of a racing car to monitor the pressure of the tire. The temperature of the whole system will arise up to 300oC during racing since the unit will be close to the brake system. The optimum time of operation should be 180 min for the unit during the race while the total operating period in a season is a maximum of 500 hours. This extensive cooling unit will not be possible due to the weight and space reasons. The materials and technologies that are needed for this unit include pressure sensor, temperature sensor, RF module, Digital-to-Analog converter, microcontroller, analogue instrumentation amplifier, display device, timer, and LED indicator.
LITERATURE REVIEW
The operation of the sensor unit will majorly deal with the measurement of temperature, pressure, and timer. This sensor should have detailed features in order for them to efficiently operate within the required guidelines, these characteristics include the ability to withstand a temperature of 300oC, ability to operate for a duration of 180 minutes during the race, and ability to have a lifespan of more than 500 hours while operating.
Components
The analogue components and semiconductor technologies that are needed to ensure safe operation include the pressure sensor, temperature sensor, RF module, Digital-to-Analog converter, microcontroller, analogue instrumentation amplifier, the display device, timer, and LED indicator. These materials and technologies of semiconductor that are required for the design of the system of wheel pressure monitoring are discussed below:
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Pressure sensor
This sensor will be used in determining the pressure of the wheels of the car. From input to the output, a sensor may possess numerous stages of conversion before it generates the electric signal. The pressure imposed in the tire will lead to alteration in strain in the diaphragm which will lead to a deflection. This will lead to general variations in the strain gauge’s resistance attached to the diaphragm. The variations in the resistance will lead to unbalance in the circuit of Strain Gauge Bridge leading to variations in the output voltage in the circuit of the bridge.
The type of pressure sensor that can be used in this design is a piezoresistive pressure sensor which is a monolithic, wafer fabricated solid-state sensor by the use of silicon processing. Since piezoresistive pressure sensors are wafer fabricated, more than 200 sensors can be produced in a single wafer.

Figure 1: Circuit diagram of a pressure sensor
The pressure sensor above function by measuring the changes in the resistance which ultimately represent variations in the pressure of the wheel. Every resistor in the pressure sensor either stretches or compresses.
Temperature sensor
This is a gadget which may be utilized in detecting and measuring hotness and coolness and changes it into an electrical signal. The temperature sensor that can be used on the wheels of this racing car is the LM35 series which has a temperature range of -550C to +1200C. This temperature sensor consists of extensive signal processing circuitry contained in the similar package as the sensors and for the sensor IC of temperature the compensation circuit is not needed.

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Figure 2: Temperature sensor, LM35
The supply of power of the temperature sensor above needs 5.5V and it has three terminals of a material which performs its function depending on the temperature to vary resistance. When there is a rise in voltage, the temperature will also rise. Temperature sensors connected directly to microprocessor input hence has the ability to reliably and directly communicate with the microprocessor. The sensor unit can effectively communicate with processors that are of low cost without the requirement of analogue to digital converter. .
Analog Instrumentation amplifier (AD8237)
The criteria of selection for the instrumentation amplifier for this design include low input offset voltage, low input bias current, and low-frequency noise. There is the necessity for the noise’s frequency to be as low as possible which is estimated as 10 Hz to 0.1Hz because the sensor output is similar. .

Figure 3: Representation of analogue instrumentation amplifier
Analog Digital Converter (ADC)
An analogue to digital converter is a device that is involved in the conversion of analogue signals such as temperature and pressure signals into the digital signal which is then fed to the microcontroller. The microcontroller can only interpret a digital signal, therefore, there is need of converting these analogue signals of temperature and pressure into digital signals by the ADC before being fed into the microcontroller. The other devices such as the display device, LED indicator, and RF module are devices that are digital which only interpret the number which as zero and one.
Microcontroller
The microcontroller is involved in accepting data from the analogue to digital converter, manipulating the data and then produce the required results in this design of wheel pressure monitoring system. In this case, the input devices include the timers, pressure sensors, and temperature sensors and then sends signals to different components which include the display device, RF module, and LED indicator.
RF Module
RF module is an abbreviation of radio frequency module and is a minute electronic device which is used for receiving and transmitting radio signals between two devices. The RF module received data concerning pressure and temperature from the sensors through the microcontroller and then transmit these signals to the display device and LED indicator where necessary steps will be performed.

Figure 4: RF Module
This wireless communication is made possible through radio frequency communication or through optical communication.
Timer
For this design of the wheel pressure monitoring system, there is need to in-cooperate a timer which will be involved in the counting of minutes during the period in which the racing car is in operation. Counting of time for this design is critical since there is need of informing the driver of the maximum time of operation of the car during a particular race which has been set to be 180 minutes for any given race.
Display Device
A typical system of tire-pressure monitoring integrates numerous functions. Temperature sensors and pressure sensors in every wheel of the racing car determine pressure and temperature at intervals that are regular. The information gotten from these sensors are sent by the signal of radio-frequency to an electric control unit which is located inside the racing car. This electric control unit is responsible for analysing the data gotten through the radio-frequency signal from the temperature and pressure sensors. Initiators interrogate sensors are required to find out possible warnings rapidly and to make sure the information that is accurate is transmitted.

Figure 5: Display Device
The display shows the data of the quantity of pressure and temperature as determined by the pressure and temperature sensors. If the temperature of the wheels is above 300oC, the temperature sensor will detect this rise in temperature and send the data to the display device which is located inside the racing car where the driver can observe it. When the pressure of the wheels is below the level that is allowable, the pressure sensor will convey the information through the RF module to the electric control unit where the pressure drop value will be showed. The driver of the car can simply note the drop in pressure value and may make a decision to increase the stop racing before the wheels could cause an accident.
LED Indicator
The LED indicator will be used to show a warning in case the information received from the pressure sensor shows that the wheels’ pressure has dropped beneath a given level which can be disastrous to the car. The LED indicator is coupled to the microprocessor such that it will only become active when the temperature goes above 300oC or pressure of the wheels reduces to 14psi or below. The LED indicator play a major role in monitoring the pressure and temperature of the wheel of the racing car by alerting the driver in case critical temperature and pressure is reached. The remedy can either be to slow down the car and add pressure in the tyres or stop applying the breaks on the wheels to reduce the temperature.

Figure 6: LED Indicator
SOLUTION
EVALUATION
The wheel pressure measuring system is an important unit that plays a critical role in the safety application of the racing cars. From the components discussed above which include the microcontroller, the display unit, temperature sensor, RF module, timer, and instrumentation amplifier are the major components that are needed for this design of wheel pressure monitoring system. The block diagram of the design after the incorporation of the components discussed above is as shown in the figure below:

Figure 7: Block diagram of wheel pressure monitoring system
Type of Materials used in making the Pressure Unit
The operation of components and made of semi-conductor has been reported at temperatures of approximately +700oC on a high end and as low as -270oC. The material used for making the outer section of the pressure sensor was SiC MOSFET which has an operational temperature of up to +650oC. However, it has been reported that temperature above +650oC will lead to degradation of mechanical performance of the pressure sensor. The Si MOSFET high temperature sensors as developed by the use of piezoresistive and capacitive sensing technology.
Operation Principle and Architecture of SiC MOSFET
This section deals with the fabrication process, materials and components used in designing a high temperature sensor made of SiC MOSFET.

Figure 8: Si MOSFET pressure sensor
When external pressure is applied, the SiC MOSFET diaphragm deflects over the dopant segregated region over the gate on the NiSi. The bending and deflection has a unique impact since it increases the value of capacitance between the substrate and diaphragm. Through the modification of the thickness of the diaphragm as well as the radius, one can attain pressure of touch point and depth which will result in variations in the value of capacitance.
Sensor fabrication
The pressure sensor discussed in this section is based on the piezoresistive pressure sensor based on silicon on insulator wafers. The first step is to acquire 400 ?m wafer then designing a pattern layer of approximately 0.34?m on the top layer of the wafer. The passive layers of SiC are deposited by LPCVD. The MOSFET ohmic contact is fabricated using self-aligned silicide process. The MOSFET multilayer films are sputtered and patterned using lift-off to form electrodes and metal interconnects. The component Ni is introduced in this step to represent the multilayer electrode.
DISCUSSION
Pressure sensor Design
The wheel pressure measuring system is an important unit that plays a critical role in the safety application of the racing cars. The system contains the microcontroller, the display unit, temperature sensor, RF module, timer, and instrumentation amplifier. The sensor is a strained gauge and a circular diaphragm type sensor joined on the opposite diaphragm’s face which was taken as the pressure of reference and the other section joined to the valve of input pressure. The strain gauge is based on the principles of piezoresistive such that strain gauge’s resistance will show a variation. The detailed circuit diagram of the wheel pressure monitoring system is as shown in the figure below:

Figure 8: Circuit diagram of the wheel pressure monitoring system
Operation of the Pressure Monitoring System
The sensor unit of this monitoring will be located at the circular diaphragm of the wheels with each unit in the four wheels joined together by the microcontroller. The temperature and pressure sensors are a strain gauge and circular diaphragm sensor type joined on the opposite diaphragm’s face which was taken as the pressure of reference and the other section joined to the valve of input pressure. The pressure sensor is used in determining the pressure of the wheels of the car. From input to the output, a sensor may possess numerous steps of conversion before it generates an electric signal. The pressure sensor works concurrently with the temperature sensor which is a device that is used in measuring and detecting coolness and hotness of the wheels’ diaphragm and converts it into an electrical signal.
The electrical signals from the pressure and temperature sensors are then fed to the analogue instrumentation amplifier whose function is to reduce unwanted noise that might have been picked have been picked up by the circuit or by the sensors while converting pressure signals and heat signals into electrical signals. The noise-free signal from the analogue instrumentation amplifier is then fed into the analogue to digital converter. An analogue to digital converter is a device that is involved in the conversion of analogue signals such as temperature and pressure signals into the digital signal which is then fed to the microcontroller.
This is because microcontroller can only interpret a digital signal, hence there is need of converting these analogue signals of pressure and temperature into digital signals by the analogue to digital converter before being fed into the microcontroller. The microcontroller is involved in accepting data from the analogue to digital converter, manipulating the data and then produce the required results in this design of wheel pressure monitoring system. This microcontroller takes input from the device it is directing and controls the device through conveying signals to diverse components of the device.
The RF module received data concerning pressure and temperature from the sensors through the microcontroller and then transmit these signals to the display device and LED indicator where necessary steps will be performed. The information gotten from these sensors are sent by the signal of radio-frequency to an electric control unit which is located inside the racing car. When the pressure of the wheels is beneath the level allowed, the pressure sensor will convey the data through the RF module to the electric control unit where the pressure drop value will be displayed. The LED indicator play a major role in monitoring the pressure and temperature of the wheel of the racing car by alerting the driver in case critical temperature and pressure is reached.
ANALYSIS
The components that have been used in the design of wheel pressure monitoring system have been analysed in Table 1 below with consideration being taken of the component, cost, model, and quantity.

Component

Model

Specification

Cost

Use

Pressure Sensor

Piezoresistive pressure sensor

0 to 15 psi

$82.00

This sensor will be used in determining the pressure of the wheels of the car.

Temperature Sensor

LM35 series

Has a range of A temperature -550C to +1200C

$75.00

A temperature sensor is a gadget used for detecting and measuring hotness and coolness and changes it into an electrical signal

RF Module

ASK RF transmitter-receiver

Frequency 433MHz or 315MHz

$6.79

The RF module received data concerning pressure and temperature from the sensors through the microcontroller and then transmit these signals to the display device and LED indicator where necessary steps will be performed.

Digital-to-Analog converter

TLV1572 Analog-to-Digital Converter

12-bit D/A converter

$169.00

An analogue to digital converter is a device that is involved in the conversion of analogue signals such as temperature and pressure signals into the digital signal which is then fed to the microcontroller.

Microcontroller

PIC16C6x/7x

2048 bytes of EPROM, 128 bytes of RAM, and CPU running at 12 MHz

$21.99

The microcontroller is involved in accepting data from the analogue to digital converter, manipulating the data and then produce the required results in this design of wheel pressure monitoring system.

Analog instrumentation amplifier

MCP602 Model

The frequency of about 10 Hz to 0.1 Hz.

$50

This device reduces unwanted noise that might have been picked have been picked up by the circuit or by the sensors while converting pressure signals and heat signals into electrical signals.

Display device

TFT LCDs

The appropriate size of the display device is 4 inches with the resolution of 800*600.

$4.20

The display shows the data of the quantity of pressure and temperature as determined by the pressure and temperature sensors

Timer

Digital clock

Up to 180 minutes

$8.45

The timer is involved in the calculating of time during the period in which the racing car is in operation.

LED indicator

HWIP-2FQD

The peak wavelength variations are up to + or -10nm and operates at a current of 20mA

$17.09

The LED indicator play a major role in monitoring the pressure and temperature of the wheel of the racing car by alerting the driver in case critical temperature and pressure is reached.

Conclusion
This report paper analyses a small sensor unit and analogy amplifier which is positioned at the when of a racing car to monitor the pressure of the tire. The materials and technologies that are needed for this unit include pressure sensor, temperature sensor, RF module, Digital-to-Analog converter, microcontroller, analogue instrumentation amplifier, display device, timer, and LED indicator. The pressure sensor will be used in determining the pressure of the wheels of the car. From input to the output, a sensor may possess numerous steps of conversion before it generates the electric signal. The temperature sensor is a used in measuring and detecting coolness and hotness and converts it into an electrical signal. The analogue instrumentation amplifier assists in reducing unwanted noise that might have been picked have been picked up by the circuit or by the sensors while converting pressure signals and heat signals into electrical signals.

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