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Senior Design 1

During my time at the University of Texas at Dallas in the spring semester I had the opportunity to lead a team of talented individuals to create the design for our senior project that we would build during the following fall semester.

This ended up being a very educational experience about what it means to fully plan out a project and present that plan under the scrutiny of other engineers within the field.

I was very lucky to have had the opportunity to lead a team of 4 in creating A project that I believe to be very interesting and not something that is typically thought of.

The Initial Idea

After multiple brainstorming sessions within the team, we determined that the project we would make was a Radio Telescope that we could use to create images of the stars.

We determined this was the best choice for multiple reasons.

1. Designing an antenna seemed like an interesting experience that none of us had before.
2. Creating an image from the resulting scan would present well and allow one to easily measure the project’s success.
3. RF was not explored in our coursework, and we saw it to learn something new.
4. As the Rest of the team was electrical engineers, it seemed like a programming light project to take on (This ended up being incorrect)

With these reasons in mind, we determined that for our Senior Design, we would create a telescope that could detect the hydrogen line and record its intensity in an image.

The Hydrogen Line

For the sake of time, I will not go into too much detail on what the hydrogen line is and will instead point you Here

But in the context of this project explanation, all you really need to know is that hydrogen will occasionally release a frequency at 1.42 GHz or 21 cm wavelength (get it) and when the entirety of the universe is made up of hydrogen, this signal is very common and varies in magnitude.

Project Goal

With the hydrogen Line in mind, we now must determine what our goals for the project will be.

Based on what we wanted to create, we determined that we wanted the following functionality for the device.

• Detect 1.42 GHz signals given off by hydrogen
• Create An Image of those signals based on the location and magnitude of the signal
• Create the device to be below $1000 in components

We then went to designing the 4 Subsystems that would make up this device. The Antenna, Signal Processing, Mounting Solution, and the program that will create the resulting image.

The Device

Antenna

^ example of a similar horn antenna

The Antenna Design we ended up going with was a horn antenna designed to capture 1.42 GHz and have the gain characteristics to detect the differences at multiple positions. Our reasoning for this form factor was simple: Manufacturing.

With the means we had, creating an antenna was already a difficult task. To make it achievable, we determined the best course of action to be designing an antenna devoid of any difficult curves, instead opting for straight angles.

Signal Processing

Once we receive a signal, we need to determine a way to format that signal into a digital format.

This is the role of the SDR we have decided to use for this design, the HackRF One.

This device will enable us to quickly take readings from the antenna getting the magnitude of the signal being received by the SDR at 1.42 Ghz and then sending that reading to our recording program.

Mounting System

For the mounting system for the antenna, we had three goals in mind.

1. Needs to be able to traverse azimuth
2. Needs to be able to traverse elevation
3. Needs to be able to communicate its current position

We determined that a 2-motor system would work best where each motor controls a range of motion.

The first Motor would change the device’s azimuth by rotating the other motor and antenna, which would be placed atop a spinning plate.

The second motor would then be placed next to the antenna and will control the antenna’s elevation and hold it in place when traversing the azimuth when scanning.

The Final piece of the mounting system will be the motor controllers themselves, which we plan to use to communicate the position of the antenna to the personal device of the user. device for the sake of creating the image.

Programming

The Program itself can be split into two separate systems. The first is the recording process, which will take the magnitude of the signal and store the result with the location of the antenna given by the motor controller.

The Second is the script for the image creation itself, which takes the recorded information and creates an image from it once it has been fully collected.

Recording Process

Above is the current plan we developed for recording the antenna’s position in between recording the signal’s magnitude through the SDR.

Upon completing the recording, the measurements will be saved into an xlsx file that we will then use to create an image using the Image process explained later.

Image Creation

The process can be boiled down into three steps for simplicity.

1. Scale the Magnitude or the Readings to Be Relative to each other and to detect outliers from the other readings.
2. Use The Location of the reading to map that magnitude to the image
3. Create and store the resulting image on the personal device of the user

With this image, we can quantify the success based on the requirements we initially created, and we are now able to share incredible photos of the hydrogen line with others!

Conclusion

With this idea and plan, we were able to present it during our senior design expo in Spring 2024 and get feedback on our design from many industry engineers. We look forward to constructing the device during this fall semester.