Esp32plus Firmware

Description

This firmware converts a Esp32 into an EZB for ARC to connect to it.

ESP32Plus is a high-performance firmware for Synthiam ARC that transforms a standard ESP32 into a powerful, network-connected robot controller with audio streaming, camera passthrough, i2c PCA9685 16-servo control, and hardware UART expansion - all in a compact, low-cost form factor.

It’s ideal for advanced robotics projects, custom robot builds, embedded systems, and WiFi-enabled robots controlled directly from Synthiam ARC.

External Camera Support (ESP32-CAM over UART)

ESP32Plus supports a dedicated camera ESP32 module (ESP32-CAM) connected over UART:

• Serial1 RX: GPIO 12
• Serial1 TX: GPIO 13

*Note: RX/TX pins can be changed in the firmware INO sourcecode.

This allows:

• Camera frames to be streamed from a second ESP32-CAM board
• ARC to treat the camera as a native EZ-Robot camera device
• Clean separation of video processing from robot control logic

This architecture keeps video capture fast and responsive without impacting servo control, networking, or audio playback.

16-Channel servo & PWM Control via PCA9685 (I2C)

ESP32Plus uses the PCA9685 16-channel PWM servo controller for reliable, jitter-free servo output:

• I2C SDA: GPIO 14
• I2C SCL: GPIO 15
• PCA9685 Address: 0x40
• PWM Frequency: 50 Hz (servo standard)

*Note: I2C pins and values can be changed in the firmware INO sourcecode.

This provides:

• Control of up to 16 servos
• Digital on/off outputs
• PWM speed control
• Hardware-timed PWM for smooth motion without CPU jitter

Servos must be powered externally and comply with the PCA9685 current-limitation requirements.

Real-Time Audio Streaming (ESP32 DAC via I2S)

ESP32Plus streams audio directly from Synthiam ARC to the ESP32’s built-in DAC using I2S DMA:

• DAC Output Pins:

  • GPIO 25 (DAC1)
  • GPIO 26 (DAC2)

*Note: If changed in the sourcecode, the pins must be DAC pins of the ESP32.

Features:

• 8-bit PCM audio streamed over WiFi
• Buffered playback using DMA
• Real-time robot sound effects, speech, beeps, and alerts

No external DAC is required - audio is output directly from the ESP32 hardware.

Automatic Network Discovery (EZ-B Scan Broadcast)

ESP32Plus automatically announces itself on the network so ARC can discover it without manual IP configuration:

• Broadcasts every few seconds using UDP
• Compatible with ARC’s EZ-B Scan feature
• Shows up as a discoverable robot controller on the local network

This makes setup fast and user-friendly - power it on, open ARC, and connect.

UART Expansion (Peripheral Serial Devices)

This firmware supports the ARC UART (#0) commands for writing, reading with a buffered input.

• Serial2 RX: GPIO 16
• Serial2 TX: GPIO 17

*Note: RX/TX pins can be changed in the firmware INO sourcecode.

This allows:

• Serial sensors
• Co-processors
• External microcontrollers
• Streaming serial devices directly into ARC

High-Performance Multi-Task Architecture

ESP32Plus uses FreeRTOS with multiple concurrent tasks:

• EZ-Robot protocol handling
• UART camera passthrough
• Audio DAC streaming
• Network discovery broadcasting

This ensures:

• No lag during audio playback
• Smooth servo updates
• High-speed TCP draining
• Stable WiFi performance under heavy load

Network Configuration

Before flashing, the firmware can be configured for:

• Access Point Mode (Robot creates its own WiFi network)
• Client Mode (Robot joins your existing WiFi network)

You must edit:

#define AP_MODE

#define WIFI_AP_SSID "YourRobotName"
#define WIFI_AP_PWD  ""

#define WIFI_CLIENT_SSID "YourWiFi"
#define WIFI_CLIENT_PWD  "YourPassword"

This gives you full control over how the robot connects to your network.

What You Need (External Hardware)

ESP32Plus intentionally stays modular:

This design keeps the system flexible and easy to expand or customize.