f4e4f184ef
Add WiFi mesh handoff infrastructure: WiFiState.msg interface: - SSID, signal strength (dBm), connection status - AP address, frequency, link quality - TX/RX rates, roaming flag - Available APs for handoff decision WiFi Monitor Node: - Signal monitoring via iwconfig/nmcli - Auto-roam at -70dBm threshold - Seamless wpa_supplicant roaming - Gateway ping (8.8.8.8) every 5s - USB tethering fallback if offline >30s - TTS warnings for connectivity issues - Coverage logging with AP transitions Features: - Configurable roaming threshold (-70dBm default) - Gateway connectivity verification - Offline detection with configurable timeout - USB tethering auto-activation/deactivation - Signal strength change logging (>5dBm) - AP transition logging - Manual rescan/tether control commands Topics: - /saltybot/wifi_state (String) - /saltybot/speech_text (String warnings) - /saltybot/wifi_cmd (String commands) Configuration: - interface: wlan0 - roam_threshold_dbm: -70 - offline_warning_timeout: 30.0 - target_ssid: SaltyLab - fallback_tether: true - coverage_log_file: /tmp/wifi_coverage.log Roaming Behavior: - Monitors signal continuously - When signal < -70dBm, scans for stronger AP - wpa_supplicant performs seamless handoff - Logs all AP transitions to coverage file Fallback Behavior: - Pings gateway every 5 seconds - If unreachable for >30s, activates USB tether - TTS alert: 'Warning: Lost WiFi connectivity...' - Auto-deactivates when WiFi restored Coverage Mapping: - Logs timestamp, SSID, signal, connected status - Tracks roaming events - Useful for mesh network optimization Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
SaltyBot WiFi Mesh Handoff (Issue #458)
Seamless WiFi AP roaming with automatic fallback to USB tethering.
Features
- Signal Monitoring: Continuous WiFi signal strength tracking via iwconfig
- Auto-Roaming: Seamless handoff to stronger AP when signal < -70dBm
- Gateway Ping: Periodic connectivity verification to 8.8.8.8
- USB Tethering Fallback: Auto-activate phone USB tether if WiFi offline >30s
- TTS Warnings: Voice alerts for connectivity issues
- Coverage Mapping: Logs all signal transitions for analysis
- wpa_supplicant Integration: Native WiFi roaming support
- Status Publishing: Real-time WiFi state on
/saltybot/wifi_state
Setup
1. WiFi Configuration
Edit /etc/wpa_supplicant/wpa_supplicant.conf:
network={
ssid="SaltyLab"
psk="password"
bgscan="simple:30:-70:600"
ap_scan=1
priority=10
}
2. Launch
ros2 launch saltybot_wifi_monitor wifi_monitor.launch.py
3. Monitor
ros2 topic echo /saltybot/wifi_state
Configuration
| Parameter | Default | Description |
|---|---|---|
interface |
wlan0 | WiFi interface |
roam_threshold_dbm |
-70 | Roaming signal threshold |
offline_warning_timeout |
30.0 | Timeout before USB fallback |
target_ssid |
SaltyLab | Target mesh SSID |
fallback_tether |
true | Enable USB tethering |
Roaming Behavior
Automatic roaming when:
- Signal < -70dBm
- Stronger AP available (>5dBm better)
- wpa_supplicant performs seamless handoff
- No ROS message disruption
Fallback Behavior
Automatic fallback when:
- Gateway ping fails for >30 seconds
- TTS warning published
- USB tethering activated
- Auto-deactivated when WiFi restored
Topics
| Topic | Type | Description |
|---|---|---|
/saltybot/wifi_state |
String | Current WiFi state |
/saltybot/speech_text |
String | TTS warnings |
/saltybot/wifi_cmd |
String | Control commands |
Coverage Log
tail -f /tmp/wifi_coverage.log
Output:
2026-03-05T09:15:23.456 | SSID:SaltyLab | Signal:-65dBm | Connected:true | Roaming:false
2026-03-05T09:15:45.789 | SSID:SaltyLab-5G | Signal:-62dBm | Connected:true | Roaming:true
Issue #458 Completion
✅ WiFi signal monitoring (iwconfig/nmcli) ✅ WiFiState.msg interface ✅ Auto-roam at -70dBm ✅ Seamless wpa_supplicant handoff ✅ Gateway ping verification ✅ USB tethering fallback ✅ TTS warnings (offline >30s) ✅ Coverage logging + AP transitions ✅ Configurable parameters ✅ Manual control commands