Project

# Title Team Members TA Documents Sponsor
13 Invertible-Control Ant-Weight Battle Bot
Ben Goldman
Jack Moran
Haocheng Bill Yang design_document1.pdf
proposal1.pdf
**TEAM MEMBERS:**
- Jack Moran (jackm6)
- Ben Goldman (bg23)

**PROBLEM:**

The primary objective is to create a bot weighing under 2lbs to disable an opponent in an ant weight combat battle bots match in a confined space. Winning a match like this often requires a high skill level to pilot a robot, especially as they get flipped or lose control when other bots attack. Additionally, many bots may suffer from reliability issues as teams overcomplicate the robotics which leads to vulnerabilities. We need a solution to maximize weapon power while simplifying the driving experience for the operator so all they need to focus on is planning attacks against other opponent bots.

**SOLUTION:**

We propose a 2lb combat battle bot designed to deliver catastrophic blows to opponents using a double sided horizontal spinning bar with an easy to use control system to allow for efficient battle. The chassis will feature a large primary weapon consisting of a horizontal spinning bar capable of delivering powerful attacks after winding up due to high inertia. This primary weapon will stick out of the front. The sides and back of the bot will be rounded in shape with no sharp edges or corners in order to deflect attacks and prevent opponent's weapons from grabbing on.

For the controls and movement, the bot will feature two wheels to enable a tank like steering system. These wheels will be enclosed within the body of the bot so that only a small section, where it would contact the ground, protrudes from the top and bottom of the bot. There would be small skid sections to allow the remainder of the body to stay low to the ground while also moving easily when on smooth surfaces.

Since the bot will have a weapon, defense system, and wheels which can operate in either orientation, this bot will be capable of operating if flipped. However, whenever the bot is inverted, the steering and controls would be inverted making it hard to command. To combat this, we will include an IMU sensor to detect if the bot has been flipped. The controls would then be inverted so that the driver does not need to focus on the orientation of the robot and can focus on controlling the weapon towards opponents as controls would be reversed automatically. The bot would be controlled from the driver's laptop.

**SOLUTION COMPONENTS:**

**Subsystem 1: Mobility and Drive System**

This subsystem is responsible for the mobility and driving capabilities of our bot. The bot needs to be highly mobile and fast in order to evade and attack other bots. In addition, this system will need to be capable of operating no matter the orientation of the bot. Using two motors for mobility will allow the bot to be able to turn very efficiently using tank like steering.
- Drive type: Differential wheeled drive (two motors).
- Wheel placement: Wheels recessed inside the chassis to protect against direct impacts. Each wheel only slightly protrudes from top and bottom of the chassis.
- Motors: High-torque brushed DC gearmotors sized for ant-weight limits.
- Control: Independent left/right motor control via H-bridges on the custom PCB.

**Subsystem 2: Spinning Weapon System**

The main weapon of our battle bot is a horizontal spinning bar. This piece will be 3D printed in a manner such that it is very strong and will not break on impact. It will be driven by the bot's third motor. In addition, this weapon must comply with ant-weight regulations. Therefore, this weapon must stop completely within 60 seconds of shutoff. The weapon provides offensive capability while keeping mechanical complexity to a minimum.
- Weapon type: Horizontal spinning bar.
- Actuation: Brushed DC motor belt driven or directly driven.
- Safety: Software-controlled spin up sequence and current monitoring to prevent overcurrent or unsafe startup.

**Subsystem 3: Orientation Detection and Control Inversion**

The battle bot will feature the use of IMU sensors to help the driver control the bot. When flipped upside down by other bots, this bot will detect the inversion and be able to invert all controls. This allows for the driver to focus on attacking and evading other bots rather than wasting energy understanding how to control a bot when it is upside down using reversed controls.
- Sensor: 6-axis IMU (accelerometer + gyroscope). Potential option: MPU-6050
- Function: Detect robot orientation (upright vs inverted).
- Control logic: Automatically invert motor commands when inverted so “forward” and “turn” remain intuitive to the operator.

**Subsystem 4: Control Electronics and Custom PCB**

The PCB and control electronics are responsible for the main control and communication of our robot. Our microcontroller will be our central controller receiving operator commands and translating them into control signals. This will interface with the IMU to determine the robot’s orientation and apply the correct control logic accordingly. This subsystem also monitors our safety conditions. It will kill all motors and enforce failsafe behavior for our weaponry if communication is lost or there is a fault.
- Microcontroller: ESP32 (Wi-Fi or Bluetooth control). Potential option: ESP32-WROOM-32E
- Wireless control: PC-based controller via Wi-Fi/BLE. This is included in the ESP32
- Motor drivers: Custom H-bridge circuits for left drive, right drive, and weapon motor.
- Power management: LiPo battery. Potential option: Turnigy Nano-Tech 3S LiPo. Would include voltage regulation for logic (3.3V) and current sensing for protection.
- Safety features: Hardware kill switch. Automatic shutdown on RF link loss

**Subsystem 5: Mechanical Design and Fabrication**

The body of the bot will be primarily 3D printed and will adhere to all requirements of an ant-weight battle bot. Primarily, this means that the bot will measure in under 2lbs for competition. The chassis will be able to be opened in order to properly build and work on the bot including access to the PCB, microcontroller, battery, and motors. This chassis will also provide all primary defense systems by being smooth and rounded everywhere other than at the front where the weapon protrudes. This prevents attacks from spinning weapons or claw like devices to do damage. In addition, weight distribution will be optimized to keep the center of mass low and stable.
- Materials: PLA+, PETG, or ABS.
- Weight limit: ≤ 2 lb total robot mass.
- Manufacturing: Fully 3D-printed chassis with modular access to electronics.

**CRITERIA FOR SUCCESS:**

**Mobility and Drive System**
- The robot remains fully drivable when inverted.
- The robot contains two wheels directly driven by motors such that front, back, and sides of each wheel are protected by the chassis.

**Spinning Weapon System**
- Uninterrupted high speed 360 degree rotation possible in both directions.
- After impact, the spinning weapon immediately starts to spin up again.
- The control system has an operational killswitch which shuts down all operations of the bot.
- Weapon comes to a complete stop within 60 seconds after shutoff.

**Orientation Detection and Control Inversion**
- Sensors detect both upright and inverted positions which are displayed on the laptop controlling the bot.
- Controls get inverted when the bot is upside down and return to normal when upright based on the use of the IMU.
- Controls invert within 300ms after bot flips.

**Control Electronics and Custom PCB**
- The robot passes all safety shutdown tests required in ant-weight battle bot rules.
- Custom PCB operates reliably without overheating or brownouts. This means it remains operational for ten or more minutes.

**Mechanical Design and Fabrication**
- The chassis of the battle bot weights in under 2lbs.
- The chassis of the battle bot is smooth and curved with no sharp corners other than on the main spinning weapon.
- The robot is competition-ready and able to participate in the ECE 445 ant-weight battle bot event.

Four Point Probe

Simon Danthinne, Ming-Yan Hsiao, Dorian Tricaud

Four Point Probe

Featured Project

# Four Point Probe

Team Members:

Simon Danthinne(simoned2)

Ming-Yan Hsiao(myhsiao2)

Dorian Tricaud (tricaud2)

# Problem:

In the manufacturing process of semiconductor wafers, numerous pieces of test equipment are essential to verify that each manufacturing step has been correctly executed. This requirement significantly raises the cost barrier for entering semiconductor manufacturing, making it challenging for students and hobbyists to gain practical experience. To address this issue, we propose developing an all-in-one four-point probe setup. This device will enable users to measure the surface resistivity of a wafer, a critical parameter that can provide insights into various properties of the wafer, such as its doping level. By offering a more accessible and cost-effective solution, we aim to lower the entry barriers and facilitate hands-on learning and experimentation in semiconductor manufacturing.

# Solution:

Our design will use an off-the-shelf four point probe head for the precision manufacturing tolerances which will be used for contact with the wafer. This wafer contact solution will then be connected to a current source precisely controlled by an IC as well as an ADC to measure the voltage. For user interface, we will have an array of buttons for user input as well as an LCD screen to provide measurement readout and parameter setup regarding wafer information. This will allow us to make better approximations for the wafer based on size and doping type.

# Solution Components:

## Subsystem 1: Measurement system

We will utilize a four-point probe head (HPS2523) with 2mm diameter gold tips to measure the sheet resistance of the silicon wafer. A DC voltage regulator (DIO6905CSH3) will be employed to force current through the two outer tips, while a 24-bit ADC (MCP3561RT-E/ST) will measure the voltage across the two inner tips, with expected measurements in the millivolt range and current operation lasting several milliseconds. Additionally, we plan to use an AC voltage regulator (TPS79633QDCQRQ1) to transiently sweep the outer tips to measure capacitances between them, which will help determine the dopants present. To accurately measure the low voltages, we will amplify the signal using an JFET op-amp (OPA140AIDGKR) to ensure it falls within the ADC’s specifications. Using these measurements, we can apply formulas with corrections for real-world factors to calculate the sheet resistance and other parameters of the wafer.

## Subsystem 2: User Input

To enable users to interact effectively with the measurement system, we will implement an array of buttons that offer various functions such as calibration, measurement setup, and measurement polling. This interface will let users configure the measurement system to ensure that the approximations are suitable for the specific properties of the wafer. The button interface will provide users with the ability to initiate calibration routines to ensure accuracy and reliability, and set up measurements by defining parameters like type, range, and size tailored to the wafer’s characteristics. Additionally, users can poll measurements to start, stop, and monitor ongoing measurements, allowing for real-time adjustments and data collection. The interface also allows users to make approximations regarding other wafer properties so the user can quickly find out more information on their wafer. This comprehensive button interface will make the measurement system user-friendly and adaptable, ensuring precise and efficient measurements tailored to the specific needs of each wafer.

## Subsystem 3: Display

To provide output to users, we will utilize a monochrome 2.4 inch 128x64 OLED LCD display driven over SPI from the MCU. This display will not only present data clearly but also serve as an interface for users to interact with the device. The monochrome LCD will be instrumental in displaying measurement results, system status, and other relevant information in a straightforward and easy-to-read format. Additionally, it will facilitate user interaction by providing visual feedback during calibration, measurement setup, and polling processes. This ensures that users can efficiently navigate and operate the device, making the overall experience intuitive and user-friendly.

# Criterion for Success:

A precise constant current can be run through the wafer for various samples

Measurement system can identify voltage (10mV range minimum) across wafer

Measurement data and calculations can be viewed on LCD

Button inputs allow us to navigate and setup measurement parameters

Total part cost per unit must be less than cheapest readily available four point probes (≤ 650 USD)

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