Building An Frc T-Shirt Cannon: Ultimate Guide

Building a T-shirt cannon robot is a fun project for students and robotics enthusiasts alike. While it may seem daunting, with the right tools and knowledge, it is possible to create a functional and safe T-shirt cannon. In this guide, we will explore the steps and considerations for building an FRC T-shirt cannon robot, from designing the chassis to assembling the cannon and ensuring safety. We will also discuss the different materials and components that can be used, and provide tips for testing and troubleshooting. By the end, you should have a clear understanding of how to build your own T-shirt cannon robot and be well on your way to creating a unique and impressive machine.

Design and build process

The design and build process for an FRC T-shirt cannon robot involves several steps and requires various materials and components. Here is a detailed overview of the process:

Planning and Materials

Firstly, gather the necessary materials and components, which may include PVC pipes, pneumatic tires and motors, motor controllers, power distribution panels, batteries, wiring, connectors, and fasteners. It is important to plan the design and ensure you have all the required parts before beginning assembly. This project can take weeks or months to complete, so having a clear plan and all the necessary materials will make the process smoother.

Assembling the Chassis

The chassis forms the base of the robot and provides mobility. Follow the instructions provided by manufacturers such as AndyMark to assemble the chassis kit, ensuring to connect motor controllers to each motor. You may also need to inflate the tires and tighten bolts. Consider using locknuts and Loctite for added security. At this stage, you can also start programming basic code for the drivetrain or find pre-made code online.

Electrical Setup

The electrical setup involves wiring the motor controllers from the chassis to the power distribution panel. Ensure all connections are solid and use power pole connectors for a secure fit. Connect the battery, insulating all connectors with electrical tape. Follow wiring diagrams to connect additional electrical components such as the RSL, Roborio, and Radio. Create a battery mount to secure the battery in place.

Bumpers

Bumpers are an important safety feature to reduce potential damage to the surroundings. Using materials such as plywood, angle brackets, pool noodles, and Cordura fabric, design and construct bumpers for your robot. You can add easy-release pins to make it easier for the robot to fit through doorways. A simple design involves using four corner bumpers. Attach the bumpers to the chassis using L-channel brackets, wood screws, bolts, and rivets or locknuts.

Mounting Electrical Components

Using an electrically isolated material such as polycarbonate or plywood, securely attach the main power components and controllers to a board. Double-check all electrical connections and refer to online resources for wiring instructions. Create a temporary mount for the electrical panel to facilitate testing.

Assembling the Cannons

Cut the PVC pipes to the desired length, typically around 3 feet. For each cannon, you will need two PVC tubes. Join the tubes with a sprinkler controller in the middle, using caps with threaded extrusions. Seal the tubes that will hold the pressure with end caps, ball valves, PVC cement, and silicone or epoxy. Repeat this process for each cannon, and attach them securely to the chassis and support beam using a combination of straps, brackets, and fasteners.

Testing

Before loading any T-shirts, test the cannons to ensure they hold pressure. Use an air compressor to fill the cannons, covering all holes in the sprinkler controller module. Release the pressure to create a loud firing noise. Gradually increase the pressure to test the firing range. Once satisfied, you can start testing with payloads, starting with light objects.

Wiring and Solenoids

Attach the sprinkler valves to the solenoids using 1/4 inch tubing. Plug the solenoids into the corresponding slots in the pneumatic control module. Label the connections for easy troubleshooting. Screw the solenoids onto a material mount near the electrical panel for better electrical management and safety. Test the solenoids in the code to ensure they make a clicking sound when activated.

Final Assembly and Testing

Construct a mount for the cannons using vertical extrusions and a crossbar to achieve the desired shooting angle. Securely fasten the cannons to the mount and the support beam. Test the robot's movement and ensure all components are functioning properly. Have a team member ready to disable the robot during testing in case of any malfunctions.

Completion

After fine-tuning and troubleshooting, your FRC T-shirt cannon robot will be ready for action! This complex project requires dedication and a range of skills, but the final result is an impressive display of technology and engineering.

Technical specifications

The T-shirt cannon robot has the following technical specifications:

• Dimensions: 28" wide, 38" long, and 18" tall.
• Top speed: 12+ feet per second.
• Capacity: 200+ shots per tank.
• Projectile range: 150+ yards.
• Barrels: 10 x 2.5" OD, 2.375" ID, 24" long.
• Power source: 12-volt, 17 AH SLA MK motorcycle battery.
• Controller: VEX PIC Micro-controller with VEXNet.
• Wireless protocol: 802.11 g Wi-Fi at 2.4 GHz.
• Solenoid valve: 1" NPT MAC type, with a flow capacity of ~16 cV and a response time of 23 ms.
• Regulator: Norgren low-pressure regulator for cylinder indexing.
• Tank: High-pressure SCUBA tank reservoir at ~3300 psi, with a low-pressure regulated SCUBA tank accumulator at ~120 psi.
• Motors: Van Door Motor for pitch adjustment and Globe Motor for barrel revolver mechanism.
• Indexing/Lock: Pneumatic cylinder with gas spring assistance.

The robot is designed to be adjustable, with a motorized pitch range from horizontal to +60 degrees, and an adjustable range via an electronic solenoid valve. It is also capable of launching other items such as racquetballs or hacky sacks. The chassis is off-road capable, with six-wheel drive, and the robot can launch 3 or more T-shirts per second.

The construction of the T-shirt cannon robot involves assembling the chassis, wiring up the electrical components, creating bumpers, and assembling and mounting the cannons. The cannons are typically made from PVC tubes, with a length of around 3 feet, and are attached to the chassis using various fasteners such as straps, brackets, and bolts. The robot is controlled remotely and can be programmed with basic code for the drivetrain.

Programming

The programming aspect of building an FRC T-shirt cannon robot is crucial to ensure its proper functioning and performance. Here is a detailed guide on the programming process:

Step 1: Basic Programming

Begin by programming basic code for the drivetrain. You can either develop your own code or utilise existing code available on platforms like GitHub. This initial programming will serve as a foundation for controlling the robot's movement.

Step 2: Electrical Wiring

The next step involves wiring up the electrical components. Connect your Power Distribution Panel to the motor controllers from your chassis. Ensure solid connections and utilise power pole connectors for a secure link. Proceed to set up your battery by connecting the battery connectors and insulating all connectors with electrical tape.

Step 3: RSL, Roborio, and Radio Connection

Follow the wiring diagram to connect additional electrical components, including the RSL (Robot Control System), Roborio (the robot's brain), and the radio. These components are integral for communication and control.

Step 4: Pneumatic Control Module

While some instructions suggest ignoring the pneumatic generator, it is essential for the T-shirt cannon's functionality. Ensure that you correctly wire up the pneumatic control module, following the provided diagrams and instructions.

Step 5: Testing

Once the electrical components are connected, it's time to test the setup. Make sure your chassis is operational by testing its movement. This will help identify any potential issues with the programming or wiring.

Step 6: Solenoid Wiring

The solenoids play a crucial role in controlling the T-shirt cannon. Using the provided tubing, attach the sprinkler valves to the solenoids, and then plug them into the corresponding slots in the pneumatic control module. Ensure proper labelling for easy troubleshooting.

Step 7: Solenoid Testing

Test the solenoids by writing code to activate them. Each solenoid should make a distinct "CLICK" sound when activated. This step ensures that the solenoids are functioning correctly and are properly integrated into the system.

Step 8: Advanced Programming

At this stage, you can delve into more advanced programming to fine-tune the performance of your FRC T-shirt cannon robot. This may include adjusting the speed, range, and firing rate to suit your specific requirements. Additionally, you can explore programming for any additional features or customisations you've incorporated into your design.

Step 9: Continuous Testing and Refinement

Throughout the programming process, it is essential to test your robot frequently. Testing will help you identify any issues or areas that require improvement. Continuously refine your code and make adjustments as needed to optimise the performance of your FRC T-shirt cannon robot.

Materials and assembly

The first step in building an FRC T-shirt cannon robot is to gather the necessary materials and components. This includes a variety of raw materials, fasteners, electrical and pneumatic parts, and tools. Here is a detailed list of the materials you will need:

• Powerpole connectors
• Pneumatic Control Modules
• 1,000 denier Cordura fabric
• #10 - 32 Nuts and Bolts
• Polycarbonate or acrylic
• 8020 T channel extrusion, sliders, brackets, and bolts
• ½ inch PVC Elbows, tees, and extrusion
• 3.5-inch PVC and end caps
• 1/2 inch Pressure Gauges
• Single-action solenoids
• 1/4 inch pneumatic tubing
• Water heater earthquake straps
• Sand or other counterweight material
• Pneumatic tires and Motors
• Motor controllers
• Power Distribution Panel
• Battery and battery connectors
• Electrical tape
• 1/2 inch to 3/4 inch plywood
• Angle brackets
• 2 1/8" pool noodles
• Polycarbonate or plywood for the power board
• PVC cement
• Silicone/epoxy
• Air compressor
• Sprinkler controller
• Caps with threaded extrusions
• Ball valve with a connection point
• 2 'Two Hole 1/2" Pipe Straps'
• Custom-cut parts
• 8020 brackets

Once you have gathered all the necessary materials, you can begin the assembly process. Here is a step-by-step guide to building your FRC T-shirt cannon robot:

Step 1: Organisation

Get a large cart to keep all your materials on and support the robot during the building process. Organisation will make the assembly process smoother and faster.

Step 2: Chassis Assembly

Assemble the chassis kit, following the instructions provided by AndyMark. Include the additional pneumatic tires and motors, connecting motor controllers to each motor as you go. Ensure the wheels are inflated and bolts are tightened.

Step 3: Electrical Setup

Connect your motor controllers from the chassis to the corresponding points on the Power Distribution Panel. Set up your battery by connecting the battery connectors and insulating all connectors with electrical tape. Follow the wiring diagram to connect your RSL, Roborio, Radio, and other electrical components.

Step 4: Bumper Creation

Create bumpers out of 1/2 inch to 3/4 inch plywood, angle brackets, 2 1/8" pool noodles, and Cordura fabric. You can add designs and easy-release pins to make it easier for the robot to fit through doorways.

Step 5: Electrical and Power Board Attachment

Use an electrically isolated material such as polycarbonate or plywood to attach the main power components and controllers to the board. Double-check your electrical work with wiring instructions provided online. Create a battery mount to secure the battery in place.

Step 6: Cannon Assembly

Cut the PVC to your desired length, typically around 3 feet. For each cannon, you will need two PVC tubes. Attach the tubes together using a sprinkler controller in the middle and caps with threaded extrusions. Choose the tubes that will hold the pressure and seal them with an end cap, ball valve, PVC cement, and silicone/epoxy if needed. Repeat this process for each cannon you want to include. Attach the cannons to the base of the chassis using pipe straps and to the front support beam using custom-cut parts, earthquake straps, zip ties, and brackets.

Step 7: Cannon Testing

Test your cannons to ensure they are holding pressure. Use an air compressor to fill up the cannons, covering all holes in the centre solenoid/sprinkler module. Then, release the pressure to create a loud noise, indicating successful firing. Gradually increase the pressure to test the cannon's performance.

Step 8: Solenoid Wiring and Attachment

Use the 1/4 inch tubing to attach the sprinkler valves to the solenoids, and plug them into the pneumatic control module. Screw the solenoids onto a single piece of material and mount them near the electrical panel for better electrical management and safety.

Step 9: Mount and Panel Creation

Use 2x2 8020 extrusions to create two vertical posts extending from the chassis. Add a crossbar to adjust the angle of the cannons to your desired shooting angle. You can also add mounting hardware for the electrical board and pneumatics at this stage.

Step 10: Cannon Security

Use pipe straps to securely fasten the bottom of the cannons to the back of the chassis. Drill holes, and secure with bolts and locknuts. Use a combination of custom-cut parts, earthquake strips, zip ties, and brackets to fasten the cannon barrels to the support beam.

Step 11: Final Testing

Test your robot by enabling someone to disable it in case of a malfunction during the testing process. Ensure the chassis is moving correctly, and the cannons are functioning as intended.

By following these steps and carefully assembling each component, you will create a functional and impressive FRC T-shirt cannon robot.

Testing

Initial Testing:

Begin by testing the basic functions of your robot. Make sure the chassis moves as intended and that the electrical components are properly connected and functioning. This includes testing the drivetrain and ensuring that the robot can be driven and manoeuvred as desired. It is important to have someone ready to disable the robot during these initial tests in case of any malfunctions.

Pressure Testing:

Before loading any T-shirts or projectiles, perform a pressure test on the cannons. Using an air compressor, fill up the cannons and ensure they can hold pressure as intended. Cover all holes in the sprinkler controller module or similar mechanism to maintain pressure.

Firing Tests:

Now, you can move on to firing tests. Start by simply releasing the pressure in the barrel while covering the hole on the sprinkler controller module. This should create a loud noise, indicating successful pressure release. Next, try firing the cannon without any payload. If these tests are successful, you can gradually introduce payloads, starting with something light and small, and working your way up to T-shirts.

Adjusting Pressure:

During the firing tests, start with a lower pressure, around 30 PSI, and gradually increase it as you gain confidence in the system. The recommended pressure for T-shirt cannons seems to be around 70 PSI, so work your way up to this level while observing the performance of the cannon.

Solenoid Testing:

Ensure that all solenoids are properly wired and make a clicking sound when activated. This is an important safety measure to confirm that the solenoids are functioning correctly before loading and firing the cannon.

Safety Precautions:

Throughout the testing process, prioritize safety. Always have a team member ready to disable the robot if any issues arise. Additionally, ensure that the robot's breakers are easily accessible. It is also recommended to test in a controlled environment, away from large crowds, to minimize potential hazards.

Refinement:

Remember, testing is an iterative process, and you may need to repeat these steps several times to fine-tune your robot's performance and ensure its reliability.

Frequently asked questions