Base Station¶

Standalone ground control station. Separate Raspberry Pi powered by its own wall adapter (5V USB). Not wired into either the GEO-DUDe or gimbal power systems.

Hardware¶

Network Configuration¶

Ethernet (eth0) — Laptop Link¶

The Pi's built-in Ethernet port connects directly to the operator laptop via a USB Ethernet adapter or small unmanaged switch. The Pi keeps a static IP on eth0 and runs DHCP for connected laptops, so the laptop side should be left on automatic/DHCP.

On macOS, the USB adapter may appear under names like "USB 10/100/1000 LAN" or a custom renamed service. Leave it on Using DHCP. No manual IP assignment is required.

The reliable operator URL is:

http://192.168.50.2/

WiFi Hotspot (wlan0) — Subsystem Link¶

The Pi runs a WiFi hotspot on wlan0 at 192.168.4.1/24. GEO-DUDe Pi and ESP32 connect to this network.

SSH Access¶

ssh zeul@192.168.50.2

Communication Links¶

The base station Pi acts as the central coordinator. The operator controls the system from a laptop connected to the base station Pi over Ethernet, which relays commands to both the GEO-DUDe servicer (via its onboard Pi) and the gimbal apparatus (via ESP32) over WiFi.

graph LR
    LAPTOP["Laptop<br/>(Operator)<br/>DHCP on 192.168.50.x"] -->|Ethernet| BASEPI["Base Station Pi<br/>(Ground Control)<br/>eth0: 192.168.50.2<br/>wlan0: 192.168.4.1"]
    BASEPI -->|WiFi| GEOPI["GEO-DUDe Pi<br/>(Servicer)<br/>192.168.4.166"]
    BASEPI -->|WiFi| ESP["ESP32<br/>(Gimbal)<br/>192.168.4.x"]
    GEOPI -->|WiFi| ESP

Network Architecture¶

The base station Pi runs a WiFi hotspot (groundstation) that both the ESP32 and GEO-DUDe Pi connect to. The laptop connects to the Pi via Ethernet (192.168.50.0/24 subnet).

IP forwarding and NAT are enabled on the Pi so the laptop can reach WiFi clients:

sudo sysctl -w net.ipv4.ip_forward=1
sudo nft add table ip nat
sudo nft add chain ip nat postrouting { type nat hook postrouting priority 100 \; }
sudo nft add rule ip nat postrouting oifname wlan0 masquerade
sudo nft add table ip filter
sudo nft add chain ip filter forward { type filter hook forward priority 0 \; policy accept \; }

On the laptop, add a route to the WiFi subnet:

sudo route add -net 192.168.4.0/24 192.168.50.2

Notes¶

• No fusing or power distribution needed — just a Pi with a USB power supply
• WiFi range should be tested with the GEO-DUDe rotating inside the gimbal apparatus
• The GEO-DUDe Pi and ESP32 also communicate directly with each other over WiFi for coordinated operation
• Laptop connects via Ethernet to the Pi (192.168.50.0/24)

Software¶

GEO-DUDe Control Web UI (wheel-control.service)¶

Flask web app exposed to operators at http://192.168.50.2/. Internally the service still runs on port 8080, with port 80 redirected to it on the groundstation Pi. Controls GEO-DUDe hardware via HTTP to 192.168.4.166:5000. Source: zeulewan/geodude-control (private).

Camera:

• Live MJPEG preview from RPi Camera Module 3 (IMX708)
• 640x480 @ 10fps, JPEG quality 50 (bandwidth-limited by WiFi)
• 180° flipped, proxied through groundstation

System Stats:

• CPU%, temperature, load average for both Pis
• Polled at 0.5Hz

MACE (Reaction Wheel) panel:

• STM32 Nucleo / SimpleFOC manual wheel control
• Direct target entry in wheel RPM, plus quick-set buttons for common values
• ENABLE, DISABLE, and STOP buttons for live control state
• CALIBRATE FOC button to run initFOC() on the wheel controller before enabling live motion
• Live wheel RPM readout from the wheel encoder over serial status polling
• Voltage limit input for tuning authority in manual mode
• Manual MACE control is mutually exclusive with the higher-level attitude control paths

Attitude Control panel:

• Closed-loop body-angle and body-rate experimentation built on the same STM32 / SimpleFOC stack
• Body angle zeroing and gyro bias calibration from the GEO-DUDe side
• Angle dial, setpoint controls, live gains, and breakaway/profile tooling
• Shared safety constraints with manual MACE control, including mutual exclusion and wheel-speed limits

PCA9685 Channels panel:

• Individual sliders for all servo channels (500-2500us for B/W/E/S, center 1500us)
• Servos always active at center on page load (continuous signal required)
• Per-channel center button, ALL CENTER button
• Slider thumb-drag only (no track click-jump), center button ramps slowly

Sensor readout:

• Live gyroscope, accelerometer, and encoder angle from GEO-DUDe IMU/encoder
• GEO-DUDe connection status and motor error reporting

Sensor Server (sensor-server.service on GEO-DUDe)¶

Flask API on GEO-DUDe (192.168.4.166:5000). Owns the PCA9685 servo path, wheel telemetry, and the STM32 / SimpleFOC serial bridge.

• GET /sensors — gyro, accel, encoder angle, RPM
• GET /system — CPU%, temperature, load average
• POST /pwm — per-channel PCA9685 control ({"channel": "B1", "pw": 1500})
• GET /pwm_health — servo write/readback health and last pulse widths
• GET /camera — MJPEG stream from RPi Camera Module 3
• POST /simplefoc — raw SimpleFOC commander bridge for the wheel controller
• GET /simplefoc/status — current wheel target / controller connectivity
• POST /simplefoc/profile/calibrate — run wheel initFOC() calibration on the STM32 side
• GET /simplefoc/control/state — live body control state
• POST /simplefoc/control/start|config|zero|stop|breakaway — higher-level wheel/body control routes

There is no longer a separate ESC-style /motor path for MACE, and the old attitude-controller.service split is obsolete. Those capabilities now live under the unified sensor-server.service + SimpleFOC stack.

Networking Notes¶

• Offline local network — no internet
• Ethernet clients get 192.168.50.x addresses automatically by DHCP from the groundstation Pi
• Use http://192.168.50.2/ for the UI; do not rely on hostname discovery for demos or field use
• WiFi bandwidth ~3 Mbps — camera stream and sensor polling are bandwidth-conscious
• GEO-DUDe SSID configured as groundstation (no space) in NetworkManager