Robotic T-Shirt Cannon

Born from the remains of failed projects of years past, this is an amalgamation of retired FIRST robotics competition components and a bucket of pneumatic parts just asking to be made into a contraption unlike ever seen before. Throughout a couple of months, a small group and I built a remote-controlled robotic t-shirt cannon that we then took to our school's pep assemblies.

Most of the programming information could not make it onto this version, as there was limited knowledge transfer from our programmer.

*This Instructable is very surface-level instruction with many knowledge gaps throughout. I apologize for anyone seriously trying to follow along to recreate this as it is a true amalgamation from years past that I have only worked to fix up and add to so there are parts that may be accidentally left out of the instruction.

**The Cannons and main Chassis were pre-assembled when it fell into our lap and with limited knowledge of how they were actually assembled the first time around this is my best recreation of how to build it from scratch

There is a lot here:

Base Robot Parts:

POE Cable:

Radio:

Chassis

Wheels:

Battery:

6 gauge wire

Can Wire

Powerpole connectors

12 gauge wire

24 gauge wire

Battery connectors

Roborio

Pneumatic Control Modules

Motors

Victor spx

Power dist panel

Breaker

RSL

Raw Materials and Fasteners:

Pool noodles

1/2 inch plywood

1,000 denier Cordura fabric

4" Angle Brackets

#10 - 32 Nuts and Bolts

Polycarbonate or acrylic

8020 T channel extrusion

8020 t sliders, brackets, and bolts

Cannons:

Middle solenoids

½ inch PVC Elbows, tees, and extrusion

3.5 inch PVC and end caps

Ball valves

1/2 inch Pressure Gauges

Single action solenoids

1/4 inch pneumatic tubing

Water heater earthquake straps

two hole pipe strap

Tools:

Wire Strippers

Pliers

5/32 Alan keys

# 10 Wrenches

Vice grips

PVC glue

silicone/epoxy

Vertical Bansaw/Miter saw

Teflon tape

soldering iron/wago lever nuts

Scissors

Software

WPI lib

VS code

FRC Driver Station

Sacrificial materials:

ram rod of sorts

t shirts

Scrap wood

Sand or other counterweight material

This is quite the project and you will likely need months to fully complete it. To start with, get a large cart to keep all your materials on that can also support the robot once you can start transporting it around. Having organization makes everything run much smoother and can help speed the process along.

Following the instructions given by AndyMark assemble the chassis kit with the additional Pneumatic tires and Motors, ensuring to connect motor controllers to each motor as you go (Label them with tape to make it easier to figure out). ensure wheels are inflated and bolts are tightened.

*You may want to use locknuts and Loctite depending on your luck

*At this point you can start programming basic code for the drivetrain or find some off of GitHub

Taking your Power Distribution Panel, plug your motor controllers from your chassis into the corresponding points on the board. Make sure all connections are solid and use the power pole connectors when going between two components (ex: between motor controller and dist panel, and between motor and motor controller).

Take this time to also set up your battery, by connecting the battery connectors and insulating all connectors (you can use electrical tape for the terminals on the battery)

Once your motor controllers are attached follow the wiring diagram to connect your RSL, Roborio, Radio, and other electrical components ( you can ignore the pneumatic generator)

(credit for image and help form attached below)

Following the general guideline from any FIRST robotics competition, make some sort of bumpers out of your 1/2 inch to 3/4 inch plywood, angle brackets, 2 1/8" pool noodles, and Cordura fabric.

If you wish you can add designs and easy-release pins to these to make it easier to fit through doorways, onto carts, etc. The simplest design is with 4 corner bumpers that have the least overall coverage but will still do the job amicably.

Brackets to attach bumpers to the chassis can be made with 2x2 L channel, wood screws, and 10-32 bolts with either Riv-nuts attached to the chassis or a locknut on the underside of the chassis (or quick release pins instead of the bolt)

Make sure to keep these on the robot at all times where it doesn't need to fit through a doorway and ensure they are well constructed. Their goal is to reduce the damage that can be done to the outside environment.

Using an electrically isolated material (Polycarbonate or Plywood) attach the main power components and controllers to the board.

Double-check all your electrical work with wiring instructions provided through https://www.youtube.com/watch?v=lGgIhxYuSHM&t=1s and various diagrams on FIRST's website until you have everything from the RSL to the pneumatic control module all wired up and electrically isolated from the rest of the cassis

If you haven't done so already through testing, make yourself a battery mount. this can be as simple as a board and a bungee cord or a custom housing (bungee cord for the win)

At this point, you can attach the connectors to the motors and plug them into the main board as well

*MAKE SURE THE BREAKER IS OBVIOUS AND ACCESSIBLE

*If you wish you can make a temporary mount for the electrical panel so you can test the drivetrain

*Now start testing to make sure your chassis moves.

Start by cutting your PVC to length, ours were about 3 feet long. make sure for each cannon you want to have you have 2 PVC tubes cut to length. You should then attach the tubes with a sprinkler controller in the middle, using caps that have threaded extrusions ideally.

After the tubes are hooked together choose the ones that will be holding the pressure and securely seal them with an end cap and ball valve (that has a connection point for the tubing), PVC cement, and silicone/epoxy if needed.

Repeat this step until you have however many cannons you want to use, and attach them at the base with 1/2 inch PVC and at the barrels with either a custom mount, earthquake straps, or zip ties (or a combination)

Make sure to add an air hookup on the end of each row of cannons you plan on creating for filling and testing

Firstly, test to ensure you are holding pressure. Using an air compressor, fill up your cannons to ensure they hold pressure as intended (note you will need to cover all holes in the center green solenoid/sprinkler module for this to work).

Now you can try and test it. (DON'T LOAD ANYTHING TO START WITH). Fill the barrel up with pressure while covering the hole on the sprinkler controller module. suddenly releasing this should cause it to make a loud noise and "fire". If this is all going correctly, you can try it with a payload (I would recommend something light and small to start)

*Shoot at around 30PSI to start with and gradually ramp up to around 70 if all is working correctly.

*video attached to show what a test fire should look like

Using the 1/4 inch tubing, attach the sprinkler valves to the solenoids and plug them into their respective slot in the pneumatic control module. (label for easy troubleshooting should a problem arise)

Once all solenoids are wired, screw them all onto a single piece of material and mount them near where your electrical panel will be. While not necessary, this helps tremendously with electrical management and the overall safety of the machine.

*In code, test to make sure all solenoids make a CLICK sound when they are being activated

Using 2x2 8020 extrusions make two posts extruding vertically from the chassis and add a crossbar that (when the cannons are leaned up against it) puts it at the angle you desire to shoot from.

Secondary mounting hardware can be added to attach your Electrical board and pneumatics at this stage as well. To accomplish this you can either add more mounting plates to the 8020 or an additional vertical bar that will allow the polycarbonate to slide into the channel snugly. (Do not attempt to mount your board until you have tested it completely and have a mount for your battery.)

Use 2 'Two Hole 1/2" Pipe Straps' to securely fasten the bottom of your cannons to the back of your chassis by folding the backside of the pipe strap behind the chassis, drilling a hole, and securing it with a 10-32 bolt and locknut.

Using any combination of custom-cut parts, water heater earthquake strips, zip ties, and 8020 brackets, securely fasten the barrels of your cannons to the support beam on the front of your chassis.

Now that your cannons are working, the chassis is working, and the two are connected, it is time to test!

If you can manage it, have someone always ready to disable the robot in case of a malfunction while testing, ideally not the one who is driving the robot.

If you run into any snags while testing or creating, here are some sites that will help you out:

Chief Delphi - for everything electrical, pneumatic, or random (Cheif Delphi has threads for almost everything)

Connection PDF - for internet/connection

WPI Lib - for programming and driver station

Pneumatics - General Manual

General Troubleshooting - For some specific errors in code

Congratulations! After weeks or months of trials and tribulations, you have succeeded in constructing one of the coolest pieces of technology available to a group of bored high schoolers in a woodshop.

Enjoy your new "Anti-Aircraft" T-shirt cannon.