Gesture Controlled Robot — ESP32 ESP-NOW

A wireless gesture-controlled robot built with two ESP32 boards communicating over ESP-NOW using MAC address pairing. Tilt your hand to drive — no phone, no Wi-Fi network, no app required.

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How it works

The system is split into two independent ESP32 units:

Transmitter (worn on hand) — reads an MPU-6050 accelerometer/gyroscope module. Tilt forward to move forward, tilt back to reverse, tilt left/right to turn. The gesture data is packed into a struct and broadcast wirelessly via ESP-NOW to the receiver's MAC address.

Receiver (mounted on robot) — listens for incoming ESP-NOW packets. On receiving a command, it drives the L298N motor driver accordingly to move the BO motors. No Wi-Fi router or pairing process needed — just power both boards and they talk instantly.

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Features

• Wireless range up to ~100m (open space) with zero latency
• No Wi-Fi network or internet required — works completely offline
• Dual-mode: gesture control + optional UART fallback commands
• Tilt threshold tuning via #define constants — no recompile needed for most adjustments
• Watchdog on receiver — motors stop automatically if signal is lost for >500ms

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Hardware

Component	Quantity	Notes
ESP32 Dev Board	2	One transmitter, one receiver
MPU-6050 (accel + gyro)	1	On transmitter hand unit
L298N Motor Driver	1	On receiver / robot chassis
BO Motor + wheel set	1 set	2WD differential drive
Caster wheel	1	Front support
18650 Li-Ion battery (2S)	2 cells	Powers receiver robot
9V battery or power bank	1	Powers transmitter hand unit
Acrylic / cardboard chassis	1	2-layer, pre-drilled
Jumper wires + breadboard	—	For prototyping

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Wiring

Transmitter ESP32 ← MPU-6050

MPU-6050	ESP32
VCC	3.3V
GND	GND
SDA	GPIO 21
SCL	GPIO 22
AD0	GND (I2C address = 0x68)

Receiver ESP32 → L298N → Motors

ESP32	L298N
GPIO 27	IN1
GPIO 26	IN2
GPIO 25	IN3
GPIO 33	IN4
GPIO 14	ENA (PWM speed — Motor A)
GPIO 12	ENB (PWM speed — Motor B)
GND	GND (shared)

Battery pack (7.4V) → L298N power input. L298N 5V out → ESP32 VIN.

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Software Setup

Prerequisites

• Arduino IDE 2.x
• ESP32 board package: https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
• Libraries (install via Library Manager):
  • ESP32 ESP-NOW — built into the ESP32 Arduino core, no separate install
  • Adafruit MPU6050
  • Adafruit Unified Sensor

Getting the receiver MAC address

Before flashing the transmitter, you need the receiver's MAC address. Flash this one-liner to the receiver ESP32 first:

#include <WiFi.h>
void setup() {
  Serial.begin(115200);
  Serial.println(WiFi.macAddress());
}
void loop() {}

Open Serial Monitor at 115200 baud. You'll see something like:

A4:CF:12:7B:3E:1F

Copy this. You'll paste it into the transmitter code in the next step.

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Flashing

Step 1 — Flash the receiver

Open receiver/receiver.ino and upload to the receiver ESP32. No changes needed.

Step 2 — Set MAC address in transmitter

Open transmitter/transmitter.ino. Find this line and replace with your receiver's MAC:

uint8_t receiverMAC[] = {0xA4, 0xCF, 0x12, 0x7B, 0x3E, 0x1F};

Each byte of the MAC address goes as a separate hex value.

Step 3 — Flash the transmitter

Upload transmitter/transmitter.ino to the transmitter ESP32.

Step 4 — Power both boards

Power on receiver first, then transmitter. The transmitter's onboard LED will blink once on successful ESP-NOW registration. After that — tilt to drive.

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Gesture mapping

Gesture	Action
Tilt forward	Move forward
Tilt backward	Reverse
Tilt left	Turn left
Tilt right	Turn right
Flat / level	Stop
Sharp downward tilt	Emergency stop

Tilt sensitivity is controlled by TILT_THRESHOLD in transmitter.ino (default: 15 degrees). Increase to require more tilt, decrease for hair-trigger response.

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Project structure

gesture-robot/
├── transmitter/
│   └── transmitter.ino      # Runs on hand unit ESP32
├── receiver/
│   └── receiver.ino         # Runs on robot ESP32
├── docs/
│   └── wiring_diagram.png   # Full circuit diagram
└── README.md

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Troubleshooting

Robot not responding to gestures

• Open Serial Monitor on receiver (115200 baud) — it prints every received packet. If nothing shows, the MAC address is wrong.
• Confirm both boards are on the same Wi-Fi channel. ESP-NOW uses Wi-Fi channel 1 by default. If your router is on a different channel, add WiFi.begin(); WiFi.channel(1); before esp_now_init().

Motors running but wrong direction

• Swap the two wires on the affected motor, or flip the IN1/IN2 logic in receiver.ino.

Jerky / unstable movement

• Increase TILT_THRESHOLD in the transmitter — you may be picking up hand tremor.
• Check that the MPU-6050 VCC is on 3.3V, not 5V. 5V will not damage it immediately but causes noisy readings on some modules.

Upload fails after connecting ESP-NOW code

• ESP-NOW initialises Wi-Fi in station mode. Before uploading new code, hold the BOOT button on the ESP32 while clicking Upload in Arduino IDE.

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ESP-NOW — why not Bluetooth or Wi-Fi?

	ESP-NOW	Bluetooth	Wi-Fi
Latency	~1ms	~20–100ms	~50–200ms
Range	~100m	~10m	~50m
Needs router	No	No	Yes
Pairing process	MAC address only	Pairing handshake	SSID + password
Power consumption	Very low	Low	High

For a real-time robot control application, ESP-NOW is the clear choice. The 1ms latency means the robot feels like a direct physical extension of your hand.

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Team

Built as a 6th semester mini-project.

Role	Responsibility
Hardware	Chassis assembly, motor wiring, sensor mounting
Firmware — Transmitter	MPU-6050 reading, gesture mapping, ESP-NOW TX
Firmware — Receiver	ESP-NOW RX, motor driver control, watchdog
Testing & integration	End-to-end testing, tuning, documentation

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License

free to use, modify, and distribute with attribution.