Specialized Spectrophotometer

I designed a specialized spectrophotometer to measure changing light intensity values. It detects 340 nm wavelengths using a UV phototransistor, while an Arduino controls the UV LED, toggling it on and off to capture a variety of readings. These readings are then averaged to improve data accuracy, providing reliable insights for analysis.`

Electrical

Component Selection

For the spectrophotometer's electronics, I selected key components after conducting thorough research:

A MOSFET transistor
UV LED and UV Sensor
9V Battery
Resistors

A significant part of the process involved researching and choosing the N-channel, enhancement-type MOSFET, which I determined to be the most ideal. The load was strategically placed above the source terminal. I opted for a MOSFET over a BJT due to its superior efficiency and faster switching capabilities. The UV LED is a 340 nm surface LED, chosen for its precision in the targeted wavelength range.

Circuit Design

To create a compact circuit powered and read by a single Arduino, I meticulously designed, redesigned, and calculated every aspect with size constraints in mind. The circuit needed to fit within the small dimensions of a 3U CubeSat, adding an extra layer of complexity to the process. Extensive research and iteration ensured the design met both functionality and size requirements. The final version is currently in the prototyping phase.

Simulation

With a completed schematic drawn, a simulation was made to identify design flaws, verify component compatibility, and optimize the circuit.

This saved time and money that would have been wasted on incorrectly bought components.

Mechanical

Component Constraints

I designed, modeled, and assembled the structure in SOLIDWORKS with a strong focus on precision, refining component constraints to achieve an exact fit. Through meticulous measurements and continuous iterative testing, I adjusted the design to a 0.1mm clearance between parts. This level of accuracy ensured that every component fit seamlessly, making it ready for lab testing.

Payload Frame

I used SOLIDWORKS to design mounting plates that would be secured to the aluminum extrusions. Each plate was designed to use minimal space within the 3U CubeSat whilst simultaneously including constraints for key components like the cuvette, UV sensor and UV LED.

I assembled the CubeSat frame using modular plates, which allowed for greater flexibility during the build process. The modular design enabled easy adjustments and reconfigurations, ensuring that the frame could be adapted to different payloads and components. This approach enhanced the overall versatility of the CubeSat, allowing for quick modifications and improvements as needed.

Software

Bluetooth Connectivity

I successfully established two-way communication between an ESP32 and both a phone and a laptop using the Bluetooth protocol, BT v4.2 BR. By configuring the ESP32 as a Bluetooth serial device, I enabled seamless data transmission, allowing it to send and receive messages reliably. I debugged connectivity issues, ensured proper pairing, and optimized the communication flow to maintain a stable connection across both devices.

Current Challenges

1. Data Readings:

One of the current challenges with our payload is ensuring more precise data readings by better constraining the LED. The constraint isn't properly fitted to the LED, so it's unsteady while taking data. This means our measurement accuracy is compromised. Refining its placement and housing will be crucial for improving consistency.

2. Software Development

With basic Bluetooth connectivity established, the next steps are to use that connection to relay data read by the UV sensor