Week 2

The different ways to simulating the circuit and the assembly of the real circuit in the 2^nd week

In this week our group found that the PSPICE software is not very suitable for the simulation of our project. We spent half of a day to simulate but finally failed to get a appropriate output. On the other hand, some components such as LM1458 amplifiers are not in the database of PSPICE. Creating a new model can be in convenient. So we changed PSPICE to Multisim. Then a new simulation can be processed easier and correctly. The circuit is shown below.

Sine wave was applied to be a simulative input to represent human’s movement. The wave-forms below as an oscilloscope are input and output. The output signal is affected by the amplifier and the comparator. This is only a simple process to test the availability of the circuit system. To achieve the goal of detect the variation of the human’s movement need to utilize more complex inputs.

After simulation, our group attempted to assemble to build the circuit on the breadboard. Using an oscilloscope to display the output signal.

But the output signal is in correct and there is no reflection when sensor detect the human motion. We will check each part of the circuit next week, and modify it.  

The circuit designing and material preparing for the first week works

Our project group -- group 17 consists of only 2 members. Our topic concentrates on the infrared sensor unit -- RE200b sensor. It is suitable for indoor detection that researchers can utilize it to build a circuit to detect human’s movement by the perception of infrared ray. A rectangle pulse can be the input voltage and become a reference. When the targeted person’s state of motion changes, the infrared ray generated by the person will influence the original pulse. Then the output pulse can be analyzed to detect the exact performance, such as rest, move, drop or rise. However, the result should only focus on the target.

The sensor will be combined with an IR filter to compose a PIR object. It will receive the waveform and deliver it to an amplifier. Then the comparator will create the result to output.

Most of the components we booked has arrived this week. However, some important ones as inductance were still not received by accidents. Our group can only simulate the circuit by the simulated circuit in the PSPICE software. However, this circuit was not designed perfectly because problems still might be hard to solve in process. We plan to improve the build of it in the 2^nd week.