# Title Team Members TA Documents Sponsor
39 Robotic T-shirt Launcher Mark III
Jiakai Zheng
Mingchen Li
Shenao Wang
Xiao Luo
Timothy Lee
## Team Members
Li Mingchen (ml110),
Zheng Jiakai (jiakaiz4),
Wang Shenao (shenaow2),
Luo Xiao (xiaoluo5)

## Project Title
**Robotic T-shirt Launcher Mark III**

## Problem
1.The previous version of MARK II is excessively bulky for convenient portability and usage. It is imperative to reduce the dimensions and weight of the T-shirt launcher.

2.The shirt launcher is equipped with insufficient spare ammunition. It is necessary to ensure a minimum of three shots or enhance its firing rate.

3.To address system uncertainties, a comprehensive risk assessment should be conducted during the design phase to identify potential sources of uncertainty and their potential impacts. Mitigation strategies, such as redundant safety mechanisms, backup systems, and robust testing procedures, can be incorporated to minimize the effects of uncertainty on the system's performance and reliability.

## Solution Overview
While preserving the achievements of ROBOTIC's T-SHIRT LAUNCHER MARK II, our team will address critical flaws. For example, the MARK II was too large and heavy for its function, and the MARK II fired too slowly. In addition, in terms of automation of the system, we will also try to achieve the unfinished goals of the MARK II and ensure safety by optimizing the launch trajectory.

## Solution Components
Launcher system: The launcher system consists of an air chamber made up of gas cylinders, gas cylinders used to inflate the air chamber, an inlet valve, an exhaust valve, an exhaust trigger, and a barometer (for detecting the air pressure in the air chamber). These components are used to rapidly inflate and launch the T shirt through differential air pressure.

Two Degree of Freedom Targeting Gimbal: This targeting gimbal consists of a stepper motor, reduction gear sets and aluminum frame structures. It consists of two degrees of freedom of motion, which enables precise control of the pitch and horizontal rotation angles in a stable manner while achieving light weight. The purpose is to adjust the position of the launcher in 3D space after receiving electrical signals from the control system so that the T-Shirt can be successfully launched to the desired place.

Control System: The Control System plays a crucial role in efficiently managing the components of the system. It encompasses a gimbal controller, actuator controllers, electromagnetic valves, and a microcontroller like Arduino. They work together to ensure smooth and accurate operations, control the release of compressed air and keep the pressure in safe operating limits.

Automation System: For the case of use on the gimbal, we want the launcher to be able to fire automatically. Therefore, the system should have a suitable function to automatically adjust the direction and force of the launch according to the situation. In addition, for safety reasons, the system will include a computer vision module to conduct spectator behaviour recognition to avoid potential accidents, such as stampedes.

## Criterion for Success
Functionality of Launcher: The launcher should be able to fire T-shirts. The force of the launch can be changed by controlling the air pressure inside the launcher at the time of launch. The system should be able to simplify the operation by pre-loading the T-shirt in a certain amount. The operator can easily operate the transmitter with the trigger.

Firing Rate: The launcher should have a relatively fast firing rate, which is determined by three key factors: the rate at which the gas chamber inflates to reach the desired pressure, the rate at which the controller controls the closing and opening of the valves, and the rate at which the T-Shirt bullet is loaded. The desired pressure of the chamber will determine the force of the shot, which can be controlled by adjusting the valve closing time, and the chamber will be equipped with a barometer to allow the operator to accurately control the force of the shot and make adjustments.

Smaller Size and Weight: Reducing size and weight was one of the main objectives of this MARK III design, and for this reason we abandoned the rotary round change design of the MARK II and adopted a loaded round change design to reduce redundant size. Secondly, the weight of the gas chamber will be reduced. Two large gas cylinders are used in the MARK II, and in fact, the small volume of a single cylinder provides gas that is perfectly adequate for firing at least 40 rounds of ammunition. Then there is the reduction of overall size and weight, which is achieved by simplifying the frame design of the transport vehicle, and the overall size of the launcher.

Safety: Since the launcher uses a pressure vessel, security considerations are very important to the system. The key parts of the launcher must have components to detect safety metrics, such as barometric values. In addition, for accidents that may occur during use, we should take into account and design safety mechanisms.

## Distribution of Work

Li Mingchen: Automation System

Zheng Jiakai: Launcher system

Wang Shenao: Targeting Gimbal System

Luo Xiao: Control System

Clickers for ZJUI Undergraduate

Bowen Li, Yue Qiu, Mu Xie, Qishen Zhou

Featured Project


Bowen Li (bowenli5)

Qishen Zhou (qishenz2)

Yue Qiu (yueq4)

Mu Xie (muxie2)


I-clicker is a useful teaching assistant tool used in undergraduate school to satisfy the requirement of course digitization and efficiency. Nowadays, most of the i-clickers used on campus have the following problems: inconsistency, high response delay, poor signal, manual matching. We are committed to making an i-clicker for our ZJUI Campus, which is economical, using 2.4G Wi-Fi signal connection, and on the computer to achieve matching. At the same time, it has to deal with the drawbacks as mentioned above.


Compared with wired machines and mobile phone software, wireless i-clickers have the following advantages: they are easy to carry, they can accurately match and identify user tags, they are difficult to cheat and would not distract students. A wireless voting system consists of a wireless i-clicker, a wireless receiver on the administrator side, and a corresponding software program. In order to solve the problem of signal reception which is common in schools, we decided to use 2.4GHz Wi-Fi signal for data transmission. In addition, different from other wireless voting devices that carry out identity confirmation and bind identity information on the hardware side, we decided to make an identity binding system on the software side, and at the same time return it in the hardware unit for customer confirmation.


A mature i-clicker should have a hardware part and a software part. The hardware part needs economical and effective hardware logic design. These include the storage and transportation of user key signals through a single chip computer program, a simple LCD1602 display to provide immediate feedback, a 2.4GHz Wi-Fi transmit-receive device for many-to-one wireless signal transmission, and a beautiful shell design. While the software component includes the conversion of hardware signals to software signals, a mature voting system, authentication of device owners, and signal return to hardware systems.


Use SCM to compile the LCD module, return user input value. STC89C52RC can easily do this. Pass data to the NRF wireless transmission module.


A wireless signal detector should be a many-to-one signal transmission system. Bluetooth is one-to-one and Radio frequency is expensive. So, Wi-Fi signal transmission is the best choice. Each detector should load a transmitter and a receiver to transmit data to the administrator and get the data transmitted by the software.


A Hard-to-Soft system is necessary in any similar design. We should write a driver to process data.


Software ought to process the data signal accurately and generate feedback to each i-clicker. Specifically, a software is needed in our design. The administrator can get user data and display it visually through statistical charts. This system should also have the function to associate user information to their answer. This is designed to score. A return signal should also be designed here. Users can receive feedback on their detector screen.


Give an internal ID number to each i-clicker. Bind identity information (such as NetID, Student number) to i-clicker internal ID number on the software. Users can get their binding information on their screen by pushing a specific button. This data will be reset when a new packet is returned by the administrator.


A beautiful shell that fits the hardware system is needed. The shell should not be too large and the buttons must fit into the hardware.


Stability: Signal should be received easily. Signal loss inside a room shouldn’t occur, especially when there is a gap of two chairs.

Affordability: I-clickers should have a low cost. This facilitates mass production and popularization on campus.

Efficiency: The process from keystroke to signal collection and transmission shouldn’t have a high delay.

Beauty: Shell design should be accepted widely and be accessible to 3D printing.

Feedback: Users should get the feedback from the administrator easily. This is useful in arousing study enthusiasm of students.

Concurrency: The system should handle signals from a great deal of students in a short period correctly.


Qishen Zhou: Software data processing system and user information identification system.

Bowen Li: Hardware-to-software data transfer system and SCM hardware logic system.

Yue Qiu: Wireless signal transmission system and processing the data returned from the administrator.

Mu Xie: 3D print shell design and physical setup for the hardware part.