WEEK 3

PREFACE TO WORK

Data acquisition is the most important part of this project. A test antenna and data acquisition system were developed with the knowledge gain from the research papers . By analyzing the collected data the system should be able to identify the material of the object and also the distance to the object from the antenna base (Pan-tilt unit).

PROGRESS

for the very basic implementation ARDUINO 2560 controller board was selected due to the use friendly programming environment ans it is easy to find the supported modules. As the accelerometer sensor MPU6050 arduino friendly sensor was used. An arduino mega 2560 development board was used for the data acquisition and its sampling frequency was 1kHz. By using serial port communication all the data feed in to the laptop from the arduino board and analyzed using python script in offline. Both time domain and frequency domain signals were analyzed and differences due to the material variation and the distance variation were obtained. Planned to implement the proper prototype setup .

CODE

Here is the python code which was used to convert time domain signal to the frequency domain and plot them all . At the same time all the raw data (Time domain data ) were saved to the csv file . 4096 data points were taken at once to analyse and the no of data points should be in a power of 2 to take the FFT (FAST FOURIER TRANSFORM ).

RESULTS

All the data were analyzed using python script and the distances were taken from the tip of the antenna. In following figures show the time domain signal of the antenna when it was hit on different materials. Since the y axis of the accelerometer sensor aline with the antenna it wasn’t give any significant variation. So here only X and Z axis data were considered.

Although it was difficult to find a significant difference in the time domain signal frequency domain analyze gave significant difference from material to material. The highest amplitude frequency component had varied according to the material.

The following file show both time domain and frequency domain plots.

REFERENCE