Soft Start - Version 2

The new version of the soft start featurea current, voltage, temperature, and humidity detection along with a programmable slew rate for smoother boot up. The board uses STM32F0 to minimize power and cost while still allowing functionality and scalability.

• Firmware

• Schematics

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Hydrophone

The Hydrophone is my current project for AUVIC which I intend to complete before the contest on July 23rd. The hydrophone system will work by sampling four individual hydrophones which will be filtered in hardware. Once the signal is buffered we will perform CFFT to find the phase shift behind the dominant signal.

This project needs a good understanding of performance of CFFT and hardware that is built to have a predictable amount of error. To do this we are using technical references by the silicon manufactures to predict final circuit accuracy and doing agile development on breadboard prototypes.

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Motor Driver

The motor driver is a circuit designed for AUvic to act as an intermediate between the motor drivers and main computer. The two communicate over UART with Rs-485 helping to minimize the noise on the line and provide protection between voltage differences.

The motor controller works by driving a hobby king motor controller using PWM. In order to get RPM feedback a wire is connected to one of the motor controller poles. The wire connects to a filter on the PCB. The Signal comes in as highly distorted sine wave and filtered in a square wave before being passed to the microcontroller timer peripheal for duty cycle and frequency. (open above image in new tab to see clearly)

• Firmware

• Schematics

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Soft Start - Version 1

Soft start v1 was the first circuit designed for AUvic. It uses a PIC microcontroller to drive a gate driver when a N-FET high when a reed switch is closed. The reason why we use this setup compared to a button is because of the cost of underwater buttons.

• Firmware

• Schematics

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Weight Dropper

The weight dropper is designed for AUvic to use in Robo Sub. The team is awarded points for dropping an object in a bucket. The weight dropper is unique because it has a permanent magnetic field holding up the weight (a bearing) while drawing no current. When the drop command is sent the current is applied dropping the weight.

One of the difficulties with this project was getting the magnetic field correct so that it canceled out the permenant magnet instead of magnetizing the ball bearing the other way. We found the best way to do this was with a look up table that took in the voltage and applied a specific duty cycle depending on that.

• Firmware

• Schematic

• Orignal Design

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Solidworks

I have gained experience using solidworks through my time with AUvic. I have modeled many different boxes and mechanism. Featured above is a servo I modeled and released on Grabcad.

• Servo on Grabcad

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