scout-robot

name	scout-robot
description	Use when controlling, connecting to, or programming a Moorebot Scout robot - covers ROS topics, SSH access, message types, and common pitfalls like md5 mismatches on roller_eye messages

Moorebot Scout Robot Control

Overview

Moorebot Scout is an ARM64 Linux robot (Debian 9 stretch, kernel 4.4) running ROS 1. Control it by publishing/subscribing to ROS topics via the master (XMLRPC on port 11311). No rosbridge needed.

Configuration: ~/.scout/config.json

Store connection details in ~/.scout/config.json so they persist across sessions. Read this file first before connecting. If it doesn't exist, discover the robot and create it.

{
  "local": {
    "scout_ip": "<LAN_IP>",
    "ssh_user": "root",
    "ssh_password": "<PASSWORD>",
    "ros_port": 11311
  },
  "tailscale": {
    "scout_ip": "<TAILSCALE_IP>",
    "scout_hostname": "<TAILSCALE_HOSTNAME>",
    "my_ip": "<YOUR_TAILSCALE_IP>",
    "ros_port": 11311
  }
}

Why two sections: Local LAN connection auto-detects the host IP for goroslib. Tailscale requires explicitly passing your own Tailscale IP (my_ip) via -local so the robot can reach your ROS subscriber.

Workflow:

1. Read ~/.scout/config.json
2. Try local.scout_ip first (faster, lower latency)
3. If local unreachable, fall back to tailscale.scout_ip with tailscale.my_ip as -local
4. If config doesn't exist, scan/ask for IP, then write the file

Connection commands:

# Local (no -local flag needed)
./scout-ctrl -host <local.scout_ip>:<ros_port> -cmd battery

# Tailscale (MUST pass -local)
./scout-ctrl -host <tailscale.scout_ip>:<ros_port> -local <tailscale.my_ip> -cmd battery

# SSH (same user/password for both)
ssh <ssh_user>@<scout_ip>

Local Connection

The Scout connects to your LAN via WiFi. Find its IP from your router or the Moorebot app.

Verify connectivity:

ping <SCOUT_IP>
nc -z -w 3 <SCOUT_IP> 11311 && echo "ROS master: OK"
nc -z -w 3 <SCOUT_IP> 22 && echo "SSH: OK"

Probe ROS master (no dependencies needed):

import xmlrpc.client
proxy = xmlrpc.client.ServerProxy('http://<SCOUT_IP>:11311/')
code, msg, state = proxy.getSystemState('/probe')
publishers, subscribers, services = state

SSH Access

Enable ROOT: In Moorebot app, tap firmware version 5 times, ROOT option appears, enter 123456. The default password plt from go-scout docs may not work on newer firmware.

Tailscale (Remote Access)

Tailscale is installed on the Scout for access outside the LAN. Kernel 4.4 has no TUN module, so it runs with --tun=userspace-networking. Init script at /etc/init.d/tailscaled. When using goroslib over Tailscale, pass -local <tailscale.my_ip> so the robot can reach your ROS subscriber.

Movement Control

Publish geometry_msgs/Twist to /cmd_vel:

Twist Field	Effect	Range
linear.y	Forward (+) / Backward (-)	0.05 - 1.0
linear.x	Strafe right (+) / left (-)	~0.2
angular.z	Rotate left (+) / right (-)	~1.5 - 3.0

Always send a zero Twist to stop after movement.

Key ROS Topics

Topic	Type	Direction	Purpose
/cmd_vel	geometry_msgs/Twist	Publish	Movement (see above)
/CoreNode/jpg	roller_eye/frame	Subscribe	Camera JPEG frames
/CoreNode/h264	roller_eye/frame	Subscribe	H264 video stream
/CoreNode/aac	roller_eye/frame	Subscribe	Audio stream
/SensorNode/simple_battery_status	roller_eye/status	Subscribe	status[0] = charging, [1] = percent
/SensorNode/imu	sensor_msgs/Imu	Subscribe	IMU orientation/acceleration
/SensorNode/tof	sensor_msgs/Range	Subscribe	Time-of-flight distance (meters)
/SensorNode/light	sensor_msgs/Illuminance	Subscribe	Light sensor
/CoreNode/obj	roller_eye/detect	Subscribe	Object detection results

Battery status[0] values: BATTERY_CHARGING=0, BATTERY_UNCHARGE=1, BATTERY_FULL=2, BATTERY_UNKNOWN=3

Key ROS Services

Service	Purpose
/nav_low_bat	Send robot to charging station (empty request/response)
/CoreNode/adjust_light	Adjust light (int32 cmd: 0=decrease, 1=increase)
/NavPathNode/nav_patrol	Start patrol
/NavPathNode/nav_patrol_stop	Stop patrol
/NavPathNode/nav_cancel	Cancel navigation
/NavPathNode/nav_list_path	List saved paths

Message Type Gotcha: roller_eye md5

ROS computes message md5 including constants. If using goroslib, you MUST include all constants in msg.Definitions or the subscriber will be rejected.

roller_eye/status (md5: 6919a5b3f28e39f677c7c81d4e5a2ef4)

Field: int32[] status. Has 29 int8 constants that must be declared:

type Status struct {
    msg.Package     `ros:"roller_eye"`
    msg.Definitions `ros:"int8 PROCESS_OK=0,int8 PROCESS_ERROR=-1,int8 OBJ_DETECT_CHARGE=1,int8 RECORD_START=1,int8 RECORD_STOP=2,int8 RECORD_ERROR=3,int8 P2P_AV_PLAYING=1,int8 P2P_AV_STOP=2,int8 P2P_AV_ERROR=3,int8 WIFI_MODE_AP=0,int8 WIFI_MODE_STA=1,int8 WIFI_STATUS_DISCONNECT=0,int8 WIFI_STATUS_CONNECTED=1,int8 WIFI_STATUS_CONNECTING=2,int8 WIFI_STATUS_WRONG_KEY=3,int8 WIFI_STATUS_CONN_FAIL=4,int8 WIFI_STATUS_STOP=5,int8 BACK_UP_DETECT=1,int8 BACK_UP_ALIGN=2,int8 BACK_UP_BACK=3,int8 BACK_UP_SUCCESS=4,int8 BACK_UP_FAIL=5,int8 BACK_UP_INACTIVE=6,int8 BACK_UP_CANCEL=7,int8 BACK_UP_REDETECT=8,int8 BATTERY_CHARGING=0,int8 BATTERY_UNCHARGE=1,int8 BATTERY_FULL=2,int8 BATTERY_UNKOWN=3"`
    Status          []int32
}

roller_eye/frame

type Frame struct {
    msg.Package     `ros:"roller_eye"`
    msg.Definitions `ros:"int8 VIDEO_STREAM_H264=0,int8 VIDEO_STREAM_JPG=1,int8 AUDIO_STREAM_AAC=2"`
    Seq             uint32
    Stamp           uint64
    Session         uint32
    Type            int8
    Oseq            uint32
    Par1            int32
    Par2            int32
    Par3            int32
    Par4            int32
    Data            []uint8
}

To find other message definitions: check ~/workspace/Scout-open-source/roller_eye/msg/*.msg and roller_eye/srv/*.srv.

scout-ctrl CLI

Download pre-built binaries from GitHub Releases (linux/amd64, linux/arm64, linux/armv7, darwin/amd64, darwin/arm64, windows/amd64). Or build from source: cd go-ctrl && go build -o scout-ctrl .

./scout-ctrl -host <SCOUT_IP>:11311 -cmd status       # list nodes/topics
./scout-ctrl -host <SCOUT_IP>:11311 -cmd battery       # battery level
./scout-ctrl -host <SCOUT_IP>:11311 -cmd camera        # save JPG snapshot
./scout-ctrl -host <SCOUT_IP>:11311 -cmd forward -speed 0.2 -time 1
./scout-ctrl -host <SCOUT_IP>:11311 -cmd backward -speed 0.2 -time 1
./scout-ctrl -host <SCOUT_IP>:11311 -cmd left -time 0.5
./scout-ctrl -host <SCOUT_IP>:11311 -cmd right -time 0.5
./scout-ctrl -host <SCOUT_IP>:11311 -cmd spin          # 360 spin
./scout-ctrl -host <SCOUT_IP>:11311 -cmd stop          # emergency stop
./scout-ctrl -host <SCOUT_IP>:11311 -cmd home          # return to charger

If ~/.scout/config.json exists, the default host is read from local.scout_ip. Otherwise pass -host explicitly.

Common Mistakes

Mistake	Fix
roller_eye/status md5 mismatch	Include ALL int8 constants in msg.Definitions
SSH password rejected	Enable ROOT via app first (tap firmware 5x, enter 123456)
apt-get 404 errors on Scout	Debian stretch is EOL; download static binaries instead
Robot doesn't move	Forward/back is linear.y, not linear.x
goroslib unable to set Host remotely	Pass -local <YOUR_IP> (required for Tailscale, not for LAN)
tailscaled: no such device	Use --tun=userspace-networking (kernel has no TUN)

Related Projects

• Scout-open-source — Moorebot official (C++/ROS, msg defs in roller_eye/msg/)
• go-scout — Third-party Go controller with gamepad + video display