Basic Wheeled Robot

Build a simple two-wheeled robot controlled by OctoMY™. This tutorial walks through hardware assembly, wiring, and basic control.

Pro Tip

Don't have all the parts? Start with a robot kit! 2WD Smart Car Kits are inexpensive and include chassis, motors, wheels, and often a motor driver - everything you need except the Arduino and phone.

What you'll build

A differential-drive robot that:

Responds to Remote control
Uses an Android phone as the brain
Can be extended with sensors and plans

        ┌───────────────────┐
        │   Android Phone   │
        │   (Agent brain)   │
        └─────────┬─────────┘
                  │ USB
        ┌─────────┴─────────┐
        │  Arduino + ArduMY │
        └────┬─────────┬────┘
             │         │
        ┌────┴───┐ ┌───┴────┐
        │ Motor  │ │ Motor  │
        │  Left  │ │ Right  │
        └────────┘ └────────┘

Parts list

Required components

Component	Quantity	Notes
Android phone	1	Android 8+
Arduino Mega/Uno	1	Mega recommended
Motor driver (L298N)	1	Dual H-bridge
DC geared motors	2	6V, with encoders optional
Wheels	2	Matched to motors
Caster wheel	1	For stability
USB OTG cable	1	Phone to Arduino
Battery pack	1	6-12V for motors
Power bank	1	For phone (optional)
Chassis	1	Acrylic, 3D printed, or kit

Tools

Screwdriver set
Soldering iron (optional)
Wire strippers
Hot glue gun

Did You Know?

The L298N motor driver can handle up to 2A per channel and 12V motors. For larger robots with more powerful motors, consider the BTS7960 driver which handles 43A!

Step 1: Prepare the chassis

Option A: Use a kit

Many robot chassis kits are available:

2WD Smart Car Kit
Pololu Romi Chassis
Any differential drive platform

Option B: 3D print

Print a simple base plate with motor mounts:

    ┌─────────────────────────────┐
    │  ○                      ○   │  ← Mounting holes
    │                             │
    │  [Motor]          [Motor]   │  ← Motor mounts
    │     ○                ○      │
    │                             │
    │          [Caster]           │  ← Rear caster
    │             ○               │
    └─────────────────────────────┘

Option C: Acrylic/wood

Cut a simple rectangular base (15x20 cm works well).

Step 2: Mount the motors

Attach motors

Secure motors to chassis using brackets or screws
Ensure wheels clear the chassis edge
Motors should face outward on opposite sides

Add the caster

Mount the caster wheel at the rear center:

Should touch ground with chassis level
Allows robot to pivot smoothly

   [Left Motor]═════════════════[Right Motor]
        │                           │
        ▼                           ▼
    (Wheel)      [Chassis]      (Wheel)
                     │
                  (Caster)

Step 3: Wire the motor driver

L298N connections

                     L298N Motor Driver
    ┌─────────────────────────────────────────────┐
    │                                             │
    │   [12V+] [GND] [5V]     Motor power input   │
    │                                             │
    │   [ENA] [IN1] [IN2] [IN3] [IN4] [ENB]      │
    │                                             │
    │   [OUT1] [OUT2]    [OUT3] [OUT4]           │
    │   └──Motor A──┘    └──Motor B──┘           │
    └─────────────────────────────────────────────┘

Wiring diagram

L298N Pin	Connect To
12V+	Battery positive
GND	Battery negative + Arduino GND
5V	Arduino 5V (or leave as output)
ENA	Arduino D9 (PWM)
IN1	Arduino D8
IN2	Arduino D7
IN3	Arduino D6
IN4	Arduino D5
ENB	Arduino D10 (PWM)
OUT1/OUT2	Left motor
OUT3/OUT4	Right motor

Security Consideration

Always use a separate power source for motors (not USB power). Motor noise can cause Arduino resets and unpredictable behavior. Keep motor power wires away from signal wires.

Step 4: Flash ArduMY firmware

Install ArduMY

Open Arduino IDE
Open the ArduMY sketch from OctoMY™ source:
```
src/libs/libardumy/arduino/ArduMYMain.ino
```

Configure for your motors:

// Motor A (Left)
#define MOTOR_A_EN  9
#define MOTOR_A_IN1 8
#define MOTOR_A_IN2 7

// Motor B (Right)
#define MOTOR_B_EN  10
#define MOTOR_B_IN1 6
#define MOTOR_B_IN2 5

Upload to Arduino

Verify

Open Serial Monitor at 115200 baud. You should see:

ArduMY v1.0 ready
Actuators: 2
Waiting for commands...

Step 5: Install OctoMY™ Agent

On the Android phone

Download OctoMY™ Agent from releases or build from source
Install the APK
Launch and create a new personality (e.g., "WheelBot")

Connect Arduino

Connect Arduino to phone via USB OTG cable
Grant USB permissions when prompted
Agent should detect the controller automatically

┌─────────────────────────────────────────────┐
│  Controller Status                           │
├─────────────────────────────────────────────┤
│                                              │
│  Device: Arduino Mega                        │
│  Status: ● Connected                         │
│  Actuators: 2 (motors.left, motors.right)    │
│                                              │
│  [Configure] [Test]                          │
│                                              │
└─────────────────────────────────────────────┘

Pro Tip

Not all USB OTG cables are created equal. If your phone doesn't detect the Arduino, try a different cable. Some cheap cables only support charging, not data.

Step 6: Configure actuators

Name the motors

Go to Settings → Hardware → Actuators
Configure each motor:

┌─────────────────────────────────────────────┐
│  Configure Actuator                          │
├─────────────────────────────────────────────┤
│                                              │
│  Name: motors.left                           │
│  Type: DC Motor                              │
│  Control: PWM + Direction                    │
│                                              │
│  PWM Pin: 9                                  │
│  Dir Pin 1: 8                                │
│  Dir Pin 2: 7                                │
│                                              │
│  [Test Motor] [Save]                         │
│                                              │
└─────────────────────────────────────────────┘

Test each motor

Use the Test Motor button to verify:

Motor spins in expected direction
Forward/reverse works correctly
If reversed, swap IN1/IN2 pins in config

Step 7: Pair with Remote

On another device

Install OctoMY™ Remote app
Launch and create a personality

Pairing process

On Remote: Tap [Pair New Agent]
On Agent phone: Navigate to Pairing
Scan the QR code or enter pairing key
Complete the trust handshake

┌─────────────────────────────────────────────┐
│  Pairing Complete                            │
├─────────────────────────────────────────────┤
│                                              │
│  Thundering Walrus (Remote)                  │
│  paired with                                 │
│  Gentle Badger (Agent)                       │
│                                              │
│  Trust Level: [████████░░] Handshake         │
│                                              │
│  [View Agent] [Done]                         │
│                                              │
└─────────────────────────────────────────────┘

Step 8: Drive your robot!

Using Remote control

On Remote, select your Agent
Tap Control
Use the virtual joystick or steering wheel

┌─────────────────────────────────────────────┐
│  Control: Gentle Badger                      │
├─────────────────────────────────────────────┤
│                                              │
│           ┌───────────────┐                  │
│           │      ▲        │                  │
│           │   ◄  ●  ►     │   Speed: 60%    │
│           │      ▼        │                  │
│           └───────────────┘                  │
│               Joystick                       │
│                                              │
│  Mode: [Joystick ▼]  [STOP]                 │
│                                              │
└─────────────────────────────────────────────┘

Control modes

The canonical control surface for any robot exposing intent:ground-drive-2d is the Ground Drive activity in Remote. It maps the joystick to forward / yaw and surfaces any optional ports (parking brake, horn, etc.) in an auto-rendered bank below.

Mode	Description
Ground Drive	Joystick → `intent:ground-drive-2d.forward` / `.yaw`; works against any consuming lobe (`differential_drive`, `legged_gait_2d`)
Scenes	Apply a pre-authored multi-channel snapshot; see Author scenes
Stanzas	Generic per-channel stanza picker — falls back to a slider bank when no purpose-built widget matches

Testing and calibration

Verify driving straight

If the robot veers left or right:

Go to Settings → Hardware → Calibration
Adjust motor trim values
Or calibrate wheel sizes if using encoders

Speed limits

For safety during testing:

Set maximum speed to 50%
Increase gradually as you gain confidence
Always have a clear path for stopping

Troubleshooting

Robot doesn't move

Issue	Solution
No power to motors	Check battery connections
Motors jitter but don't spin	Battery too weak, use higher voltage
Arduino not detected	Try different USB cable/port
Only one motor works	Check motor driver wiring

Robot moves erratically

Issue	Solution
Sudden direction changes	Check for loose connections
Intermittent stops	Battery running low
Opposite direction	Swap IN1/IN2 in configuration

Connection issues

Issue	Solution
Remote can't find Agent	Check both on same network
Pairing fails	Restart both apps, try again
High latency	Move closer, reduce interference

Next steps

Now that your basic robot works:

Add sensors - Sensor Setup
Write a plan - Create a Plan
Build more complex bots - Arduino Integration