Week 1

 Week 1 Simulation

1.1 PIR simulation

This week we checked all the ordered components and equipment. We plan to build an infrared automatic door making use of PIR sensor to detect human motion. Before building the circuit in reality we firstly built an analogous circuit through software such as Multism to see how it works which contains a PIR sensor. However, in the Multisim software, there is no PIR sensor component, power supply, which can generate sinewave, is used to replace the signal generated from the PIR sensor.

Figure1 PIR sensor simulation

After finishing building the circuit in Multisim software, we simulate the circuit part by part. The first part is the amplifier, which is used to amplify the input signal. This is shown in Fig.2, and the result is shown in Fig.3.


Figure 2 The first part of the circuit

Figure 3 The result of the simulation for the first part

According to Fig.3, the blue signal is the output signal and the green signal is the input signal, and the input signal is amplified about 10 times. Furthermore, there is a phase shift between the input and output signal, because many capacitors, which have an expression 1/jwC, were used in the circuit. The higher frequency, the higher the phase shift.

The second part is another amplifier to amplify the input signal. In other words, PIR sensor detects motion and outputs a signal that is very weak, which means it is not enough to amplify the signal generated from PIR sensor once time. The circuit and the result are shown in Fig.4 and Fig.5.

Figure 4 The second part of the circuit

Figure 5 The result of the simulation for the second part


The third part is a comparator, which is used to digitalize the input signal, which means the output signal should be a square wave. The circuit and the result are shown in Fig.6 and Fig.7


Figure 6 The third part of the circuit


Figure 7 The result of the simulation for the third part

1.2 Ultrasonic sensor simulation

To simulate the ultrasonic sensor, we use Tinkercad. The function of the ultrasonic sensor is that when people are approaching the sensor, the Arduino will drive the motor rotating forward 1 second to open the door and rotate back to close the door. The circuit is shown in Figure 8


Figure 8 Ultrasonic sensor

1.3 IR remote sensor
In order to make our project looks better, we used a 7-segment display to display 'hello' to greet when people scanning the card.
Figure 9 7-segment display


                                                     Figure 10 The circuit diagram of the whole

Figure 10 shows the ideal schematic circuit, which is built-in in Week 1. In our final stage, we plan to build a circuit as the picture shown below to use the PIR sensor to control the automatic door. In the future, we hope we can simplify this circuit and use fewer Arduino boards. 


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Week 3

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 Week 3 PIR sensor connection This week we tried to build the whole circuit according to the circuit diagram which is shown in Fig.1,  and use PIR sensor to detect human movement and output signal.  Figure 1 The PIR sensor diagram Since the Fig.1 circuit diagram is a little bit complex, we simplify the circuit, which is shown in Figure 2. Figure 2 Simplified circuit diagram of PIR Firstly, we built the first part, which is amplifier 1. We redesign the circuit and try to delete the Arduino board to make the circuit more simple. Resistors and capacitors are also used to protect all the elements. However, in the first few attempts, we cannot sketch the output signal. Nothing useful was displayed on the oscilloscope.                                                         Figure 3 PIR connection of the first part In our assumption, we thi...
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Week 4

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Week 4 Finish building the PIR circuit and package. Last week, we have finished the first amplifier of the PIR circuit, and this week, we built the second amplifier and comparator which is shown in Figure 1. Figure 1 (PIR sensor circuit) Meanwhile, we connected a LED light to the output of the comparator. When nobody moves in front of the PIR sensor, the light will be turned on, and when the human motion is detected the LED will flash which is shown in the video. We infer that when no one passes through the PIR sensor, there is always a DC signal in the circuit because we used a power supply to supply DC voltage to the amplifier. The reason for this phenomenon is that the final part is Op-amp Comparator, which is used to digitalize the signal, and we choose the non-inverter comparator circuit.   When there is no input signal, the output signal is the reference voltage, if there is an input signal which is similar to a sinewave, which makes the output signal up and down like a squar...
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