Upgrades

Dual Gamepads

There are many ways to split robot control across two gamepads. We recommend testing different combinations with your team to decide what feels the most comfortable to you!

This version of the program is intended to be just one example for using two gamepads. Arm and wrist control has been moved to a second gamepad while the main gamepad handles driving and the servos on the intake and claw.

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Starterbot2025TeleOpBlocksTwoGamepad.blk

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The associated gamepad for a button input can be changed at any time by clicking on the block's dropdown:

Switching arm control to gamepad 2

Arcade Drive

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Starterbot2025TeleOpBlocksArcade.blk

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In this example code, we changed our drive function to only be on the left stick!

Arcade Drive Code

You can learn about arcade style of driving in Hello Robot!

When changing a function name this will automatically change throughout the entire code to reflect the new name.

Mecanum Drive

Upgrading to a Mecanum Drivetrain (REV-45-2470) allows for new kinds of movement giving the robot the ability to strafe side-to-side across the field.

For Mecanum Drive each wheel has an individual motor!

REV's Mecanum Drivetrain Kit V2

The FTC Starter Kit V3.1 can be upgraded to the Mecanum Drivetrain V1 following this guide.

Upgrading from the FTC Starter Kit V3.1 to Mecanum Drivetrain V2:

The following additional parts are needed:

• UltraPlanetary Gearbox Kit & HD Hex Motor - QTY 2

• Ultra 90 Degree Gearbox - QTY 4

• 75mm Mecanum Wheel Set - QTY 1 (set of 4)

• M3 x 6mm HexCap Screws 50 Pack - QTY 1

• Expansion Hub (QTY 1) OR SPARKmini Motor Controller (QTY 2)

Full build instructions can be found here!

Example Mecanum Drive Program

How a Mecanum Drivetrain is programmed largely depends on the driver's preference for how the controller is configured.

In our provided example, the left joystick controls forward/back and strafe then the right joystick controls turning. This code is based on the sample provided by FIRST in Blocks (BasicOmniOpMode).

Mecanum Demo Blocks Code:

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Starterbot2025Mecanum.blk

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Mecanum Configuration File:

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StarterBotMecanum.xml

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Mecanum Configuration - Control Hub and Expansion Hub

Port Type	Hub	Port Number	Device Type	Name
Motor	Control Hub	0	REV Robotics Ultraplanetary HD Hex Motor	frontLeft
Motor	Control Hub	1	REV Robotics Ultraplanetary HD Hex Motor	backLeft
Motor	Control Hub	2	REV Robotics Ultraplanetary HD Hex Motor	frontRight
Motor	Control Hub	3	REV Robotics Ultraplanetary HD Hex Motor	backRight
Servo	Control Hub	4	Servo	claw
Servo	Control Hub	5	Continuous Servo	intake
Motor	Expansion Hub	0	REV Robotics Core Hex Motor	wrist
Motor	Expansion Hub	1	REV Robotics Ultraplanetary HD Hex Motor	arm

Mecanum Code Breakdown

Before diving into mecanum, double check the direction your motors and wheels are turning. They may need to be reversed if you're experiencing jittering or inverted controls!

Add a block to change the set direction during initialization.

Motors are set to RUN_WITHOUT_ENCODER are the beginning of the code

At the very beginning of our program the drivetrain motors are set to RUN_WITHOUT_ENCODER.

Our mecanum drive function

We need to create some new variables in order to use mecanum. Let's break those down first:

Variable	Purpose
FB	Moving forward and backwards
Strafe	Strafing side to side
Turn	Turning left and right
leftFrontPower	Sets the front left motor power
rightFrontPower	Sets the front right motor power
leftBackPower	Sets the back left motor power
rightBackPower	Sets the back right motor power
max	This is used to check that our values do not exceed the expected range - similar to the "clip" block

At the beginning of the MECANUM_DRIVE function, our variables for each movement direction are being set to the value generated by the movement of the matching joystick axis.

Forward/back is on left Y, strafe on left X, and turning on right X

Since we now have four motors in play, our equation for setting the appropriate power to each motor gets a little more complicated.

Our robot first needs to determine the combined movement of the left stick then calculate with the right stick's value. This allows for movement when the left joystick is at an angle, such as strafing along a diagonal!

Calculating motor power

Next, similar to our original drivetrain code, there's a chance a value may fall outside the range of the motor's power (-1 to 1). Therefore, we want our robot to check and bring those values back into range so we don't miss any inputs.

Making sure our power range is between -1 to 1

For our last step, our robot sets the power of each pair of motors based on all our calculations!

Setting motor power

Tips, Tricks, & Upgrades Video Walkthrough