EZ-B V4 by EZ-Robot

What is the EZ-B v4?

What you can do with the EZ-B v4 in Synthiam

Every robot skill that uses an EZB works with the EZ-B v4. Add skills to a workspace, pick a port, and the robot responds.

Adc Monitor in ARCx reading EZB analog ports: a distance graph, a battery gauge with a low alarm, and a light level.

A project can use several EZBs at once, for example an EZ-B v4 for the head and arms and another for the drive base. Each board gets an index (EZB 0, EZB 1, ...) in the Ezb Connection skill, and every robot skill and script picks a board by that index.

Where everything plugs in

The EZ-B v4 has 24 digital ports (D0–D23), 8 analog ports (A0–A7), 3 UARTs, 3 I²C headers, a camera connector and a reset button (press it with a small pin).

Ports are not all the same. Digital ports send and read control signals, analog ports measure a voltage, and I²C and UART ports speak communication protocols. A device in the wrong type of port may not work, and can be damaged if the power on that port does not match what it expects.

3-pin GVS connectors. Most ports have three pins: Ground, Voltage (power) and Signal. Ground and Voltage power the device; Signal is the wire the EZ-B reads or writes, such as a servo's position command. On most servos the black or brown wire is ground: line it up with the black side of the port. A device plugged in backwards may not work or may be damaged.

UART serial devices

UART ports talk to TTL serial devices in both directions: motor controllers, GPS units, smart servos or another microcontroller. Each UART has a 5,000-byte receive buffer and runs from 1 to 3,750,000 bps. Always cross the data lines: EZ-B TX to the device's RX, EZ-B RX to the device's TX, and connect the grounds together.

• ARCx (JavaScript): UART.initHardwareUart(), UART.hardwareUartWrite(), UART.hardwareUartRead(), UART.hardwareUartAvailable(), or the UART blocks in Blockly.
• ARC (EZ-Script): UARTInit(), UARTWrite(), UARTRead(), UARTAvailable().

Status LED and sounds

The RGB LED on the top board and the voice prompts from the speaker tell you what the EZ-B v4 is doing. The board speaks on start-up, on a successful or failed network connection, and when the battery is low.

Access point mode or client mode

AP mode (direct connect) – start here

The EZ-B creates its own Wi-Fi network and your computer joins it. This is the default after a factory reset and works anywhere, with no router. Your computer loses internet access while it is joined, unless it has a second network adapter. The board is at 192.168.1.1.

Client mode (join your Wi-Fi)

The EZ-B joins your home, school or office network like any other device. Your computer keeps its internet, and several devices can reach the robot. You need the network's credentials, and the board gets an address from your router; the EZB scanner in ARCx and ARC finds it for you.

Switch modes in the board's web configuration page. With factory settings, join the EZ-B's Wi-Fi network and open http://192.168.1.1 (use http, not https; the web server does not use SSL). In client mode, browse to the address your router gave the board. The page also sets the Wi-Fi security (WPA2, WPA or WEP), the broadcast channel (1–11; 1, 6 or 11 are recommended), the battery monitor and the serial option. A Telnet interface is available too.

Web configuration (AP mode):  http://192.168.1.1
Telnet (AP mode):             telnet 192.168.1.1 8080
EZB connection port:          23   (192.168.1.1 or 192.168.1.1:23 in Ezb Connection)
Camera port:                  24   (192.168.1.1 or 192.168.1.1:24 in Camera Source (ezb))

To go back to defaults, press the reset button momentarily while the board is powered. All network settings return to AP mode.

Connecting over USB serial

A USB-to-TTL serial adapter wired to the camera port connects a computer straight to the EZ-B v4, bypassing Wi-Fi. It helps where there is a lot of wireless interference, or when the computer is mounted in the robot.

EZ-B v4 camera port	USB serial adapter
TX	RX
RX	TX
GND	GND

1. Join the EZ-B's Wi-Fi and open http://192.168.1.1. On the Advanced tab set the serial baud rate (the fastest your adapter supports, up to 921600) and save. The EZ-B restarts.
2. In ARCx, open the Ezb Connection configuration, select the board, and set the same Baud rate under Connection.
3. Enter the adapter's port (COM3 on Windows, /dev/ttyUSB0 on Linux) as the address and connect. In ARC, pick the COM port in the connection control.

Good to know

• The camera does not work while serial is enabled, and over Wi-Fi the board then only offers its web page and Telnet.
• There is no connect chime over serial.
• Over serial the board may identify as EZ-B v4.x/1 (Comm 1) because the link bypasses the Wi-Fi module. This is expected.
• Use a short cable (about 15–30 cm), ideally shielded or with TX/GND and RX/GND twisted together. A firmware update may be needed on older boards.
• To return to Wi-Fi, turn serial off on the web page or press the reset button.

Wiring from EZ-Robot's Serial/USB connectivity instructions.

Eyes and a voice

EZ-Robot Camera (v2)

The camera plugs into the dedicated camera port with a 6-pin cable. The connector is keyed so it only fits one way: if it does not slide in easily, check the alignment rather than forcing it.

In ARCx, add Camera Source (ezb), pick the camera from the address list (or type the board's address; port 24 is the default) and press Start. It reconnects on its own if the link drops. Its window title is the video source name that Face Tracking, Color Tracking, recording and AI skills use. In ARC, use the Camera Device skill.

Speaker and sound

The amplified speaker output is rated 0.3 W; use an 8 Ω 0.5 W speaker on the SPKR pins. A non-amplified signal from the processor's DAC is on an exposed pad in the audio area; only use it if you know what you are doing, because it connects straight to the microcontroller.

In ARCx, open the Ezb Connection configuration, choose Project audio and set Play audio through to EZB speaker: every robot skill's speech and sound then comes out of the robot. Microphone Playback (ezb) records your own voice into slots and plays them from the robot. In ARC, use SoundBoard (EZB) and the EZB speech commands.

Microphone Playback (ezb): record into a slot, play it out of the EZ-B's speaker.

Read this before plugging anything in

Power is where most beginners run into trouble. The EZ-B v4 runs on 4.5–16 V, but your servos and sensors probably do not.

Electrical characteristics

Vin is the battery or DC supply voltage minus the input diode's drop (0.14–0.36 V, depending on current). Vcc is the 3.3 V from the on-board switching regulator. Digital I/O reads or outputs 0 V (low) or 3.3 V (high). ADC converts a 0–3.3 V input to a number. I²C is a two-wire bus (SDA and SCL) shared by several devices. Do not mix 5 V and 3.3 V devices on the I²C bus: 5 V pull-ups can damage the 3.3 V parts. Source: EZ-Robot EZ-B v4 datasheet.

Move your first servo with ARCx

1. Power the EZ-B safely. Use a battery voltage your servos and accessories can handle (see Power above). The board plays a start-up sound and the LED flashes blue.
2. Join the EZ-B's Wi-Fi. On the computer that will run ARCx, connect to the EZ-B's network (AP mode). Later you can switch the board to client mode so the robot, the ARCx computer and your phone or tablet are all on your own network.
3. Install ARCx on that computer: Windows 10/11, Ubuntu 24.04 or a Raspberry Pi running Ubuntu 24.04. Download ARCx, start it and open it in a browser.
4. Add the Ezb Connection robot skill from the Communication category. Type or pick the board's address and press the green connect button.

   192.168.1.1        (AP mode)
   192.168.1.50       (client mode: the address your router gave it)
   COM3 / /dev/ttyUSB0  (USB serial adapter)

5. Move a servo. Plug a servo into D0 with the ground wire on the black side, add the Servo skill, choose D0 and drag the slider slowly at first.
6. Add the camera and a voice. Add Camera Source (ezb) and press Start, then set Project audio to EZB speaker so the robot talks. From here, add sensors, movement panels, tracking and AI.

Using ARC on Windows instead? Join the EZ-B's Wi-Fi, open ARC, enter 192.168.1.1 in the EZB Connection skill and press Connect.

The Ezb Connection window: one row per board.

Board settings: a description, a connection script that runs every time the board connects, serial and battery options.

Both work. ARCx is recommended.

The EZ-B v4 is fully supported by both Synthiam platforms. Start new robots in ARCx; keep existing ARC projects in ARC if you prefer.

Inside the EZ-B v4

When something does not work

Frequently asked questions