Question

find suitable sensors for each application outlined below. In each case, based on the datasheet, create a table which shows: name, company, price, input range, output range, linearity, sensitivity, precision, accuracy, offset and response time of the introduced sensors.

a. An embedded system to measure human body’s temperature.

b. An embedded system to measure car engine temperature.

c. An embedded system to measure tire air pressure.

d. An embedded system to measure PH of tap water.

e. An embedded system to measure mechanical vibration of an electric motor, which spins 0-5000 RPM.

Answer 1

	NAME	COMPANY	PRICE	MEASUREMENT RANGE	LINEARITY	SENSTIVITY	PRECISION	ACCURACY	OFFSET & RESPONSE TIME
A	NTC THERMISTOR	MURATA	$0.15	-400C TO +1250C	LINEAR	-3% to -6% per °C	0.10C	0.05°C to 1.00°C	X1
B	Coolant Temperature Sensor (CTS)	BOSCH	$10	-400C TO 1300C	LINEAR	0% to -10% per °C	0.10C	± 1.4°C@25°C ± 3.4°C@100°C	X2
C	Tire Pressure Monitoring System (TPMS)	bridgestone	$80	100 to 450 kPa / 100 to 900kPa	LINEAR	±18.75%		±1PSI	2ms
D	pH PROBE	LUSTER LEAF	$13	0 to 14.00 pH	LINEAR	0.002 pH	0 - 14 pH, 0 - 100°C	± 0.1pH (25C)	95% in 1s
E	VIBRATION SENSOR	PCB PIEZOELECTRIC	$15	±50 g (±490 m/s²)	NON-LINEAR	(±10%) 100 mV/g (10.2 mV/(m/s²))	?7 %	±10%	?3.0 sec

X1-The speed of response of an NTC sensor is characterized by its time constant. This is the time for the sensor’s temperature to change by 63.2 % (i.e. 1 to 1/e) of the total change that occurs when the sensor is subjected to a very rapid change in temperature.

X2-Response time tau 63 in still water < 15 s