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Nt1210 Lab 2.1

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2.2.1 Circuit Implementation
This part deals with the design of the circuit required for the force sensor. It can again be divided into four parts. The reference is taken from FlexiForce (A201 Manual). The following subsection explains in details about each one of them.
• Dual power low voltage drop power supply
Description The advantages of low-dropout regulator is its ability to limit the power dissipation to achieve higher efficiency. They can maintain regulation with small differences between supply voltage and load voltage. We can make it more smart by using
SHUTDOWN input allows the regulator to be turned off with a logic level signal.
Negative 5 volt output voltage Negative 5 volts is required as one of the inputs to the sensor. Following …show more content…

The transfer function is given by :
V out1 = (1 + Rpot/Rsensor) ∗ V ref where, Rpot = resistance of pot(ohms).
Rsensor = resistance of sensor(ohm).
V ref = reference voltage of 0.5 volts(volts).
Difference Amplifier To subtract the offset voltage of 0.5 volts from the noninverting amplifier and then add gain to adjust the output to 0-5 volts is the purpose of this circuit(see Figure 2.1 on pin 6,5,7 of MCP6002).
The equation involved in this circuit is :
V out2 = (1.107 ∗ V out1)V ref where, V out2 = output voltage obtained(volts).
V out1 = output voltage from non-inverting amplifier(volts).
V ref = reference voltage of 0.5 volts(volts).
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Filter Circuit In the circuit the capacitors are present in power supply(see Figure 2.1 on pin 1,4,8,5 of LP2951), also as an input capacitor in the signal processing circuit(see
Figure 2.1 on pin 8 of MCP6002). This helps to reduce noise in the form of ripple in an output voltage, where on the one hand capacitors with large value handles …show more content…

Following are the components required for the signal processing circuit:
– MCP6002 - Input- 1.8 volts to 6 volts. 2 op-amps in a chip.
– Resistor - 100 kilo ohm,124 kilo(resistors connected in series) ohm,150 kilo ohm
– Capacitor - 4.7 micro farad,470 pico farad,0.1 micro farad,0.01 micro farad
– Pot - 15 turn,500 kilo ohm
• Sensor
Description The sensor part of the circuit consists of Flexi Force Sensor A201 which is a piezoresistive sensor, based on the concept that electrical resistance changes when mechanical strain is applied. The reason for choosing this sensor is its simplicity and ability to measure a wide range of forces between 4-445 Newtons.
In the circuit(see Figure 2.1 on pin SV1-1 and SV1-2 of connector) requires a supply voltage of +5 Volts and -5 Volts. Following are the pre-setting which need to be done before start testing with the circuit.
Pre-settings before measurement As mentioned on the specification sheet FlexiForce
(A201 Manual) (see Figure 2.3) of the sensor, before gathering data/performing experiment following activities should be performed with the

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