Infrared sensors Week 4 - Circuit testing

This is the fourth week of our group project. We have completed the circuit building on the breadboard fundamentally. Our main work was to test the circuit and observed the output signal of different amplifiers by the oscilloscope. We moved our hands over the sensor and got the following results as showed from the figure 1 to figure 3. During the testing, we had to adjust different amplitudes and frequencies because of the effect of the amplifiers in order to get the obvious implus. 

Figure 1: The output signal of the first amplifier.

Figure 2: The output signal of the second amplifier.

Figure 3: The output signal of the third amplifier.

We also transcribed a video of the output signal of the third amplifier, the video below shows the results.

Then, we added a LED on the circuit and tested the circuit when people walked through the sensor. The video below shows the experiment results.

There were also some disadvantages, the sensor was not sensitive enough, and the distance from people to the sensor was limited. The group suspected it was the problem with circuit connection. in addition, the signal could no tlast for a long time. 

In summary, we finished all of the circuit building in this week, in order to get the reasonable result, we tested the circuit again and again. We corrected the wrong direction of the movement signals and now signals as the simulation shown can be basically displayed on the oscilloscope. Appreciate size of lens were found. Week 5 will be the last week, all technical things should be done. We will try to overcome those challenges and get satisfying results.