A biomimetic seahorse-shaped underwater ROV that scouts ahead for anglers. Stereo vision maps underwater structure, locates fish, and streams live depth-mapped video to your phone. Designed for both freshwater and saltwater, boat and shore deployment.
You're at the bank of a river. Pull the seahorse from your pack, power it on, toss it in. It rights itself and you see a live stereo depth-mapped feed on your phone — bottom structure, drop-offs, submerged logs, weed beds, and actual fish. Steer it upstream, find a deep pool behind a boulder with fish holding, mark the GPS spot, recall the seahorse, and start casting to that exact position. Works from a boat too — drop it over the side and let it scout the area before you anchor up.
Interactive — drag to rotate, scroll to zoom, right-click to pan.
The segmented body is a modular platform. The L-shaped plates, spine channel, joint system, and servo fin mount are identical across every size. You're just snapping together more or fewer segments. The head is always the head. The tail is always the tail. The middle stretches or shrinks. Like DJI's Mini → Air → Mavic line, but built from the same physical components.
Upgrade path: A Mini buyer who gets hooked can literally buy more segments, a bigger battery, and additional fin rays to upgrade to a Scout. That's a retention model DJI doesn't have — their products are separate platforms. Yours are the same platform at different scales.
Use: Wade fisherman. Peek under a cut bank, check a pool. Fits in a vest pocket. Cheap, expendable. The gateway product.
Est. ~$150–200
Use: Boat + shore angler. Map structure, anchor and observe, mark waypoints. The sweet spot. This is MVP 1.
Est. ~$350–450
Use: Guide, tournament angler. Transit a kilometer, scout multiple spots, long-duration patrol. The serious tool.
Est. ~$700–1000
The seahorse's dorsal fin oscillates at up to 35Hz in nature. We replicate this with a series of servo-driven fin rays running along the dorsal (top) ridge of the body. A sine wave propagates down the array — the frequency controls speed, amplitude controls power, and wave direction controls forward/reverse.
This is genuinely silent propulsion. Traditional thrusters create pressure waves that fish detect through their lateral line from meters away. An undulating fin mimics the movement of actual marine life and produces minimal turbulence. This is arguably the product's biggest competitive advantage over conventional ROVs.
MVP 1: Manual adjustable ballast weights. Velcro-mounted lead/steel weights on the underside. Swap weight amounts when switching salt ↔ fresh. Simple, reliable, no moving parts.
Future: Active buoyancy engine. Small syringe pump in the mid segment — push water into a bladder to sink, push it out to rise. Automated depth hold. Auto-compensates for salt vs fresh density difference (~2.5% buoyancy shift).
The seahorse's tail is its anchor. It wraps around coral, seaweed, or structure and holds position with zero energy expenditure. We replicate this with a tendon-driven curling mechanism — one servo, two cables, and the segmented tail curls like the real thing.
This solves the biggest energy problem in patrol mode: holding position in current. Instead of burning battery fighting drift, the tail grips structure and the entire propulsion system shuts down. Combined with energy harvesting, the ROV can potentially run energy-positive in patrol mode — harvesting more than it consumes.
Phase 1 focuses on validating stereo underwater vision. Waterproofing is minimal — acrylic tube or dry bag enclosure. No custom PCB. Off-the-shelf components on a dev platform. Get it in the water fast, prove the cameras work, iterate from there.
| Component | Qty | Est. |
|---|---|---|
|
Raspberry Pi 5 (4GB)
Dual CSI-2, Cortex-A76 quad, native stereo camera support
|
1 | $60 |
|
RPi Camera Module v2 (IMX219)
8MP, fixed focus (better for stereo than autofocus v3). Side-mounted in eye sockets with flat optical viewports.
|
2 | $50 |
|
CSI-2 Adapter Cable (22→15 pin)
Pi 5 uses 22-pin, camera modules are 15-pin
|
2 | $6 |
|
MicroSD Card (64GB, A2/U3)
Fast read for stereo capture + video logging
|
1 | $12 |
| Component | Qty | Est. |
|---|---|---|
|
IMU — BNO085 or ICM-20948
9-DOF, orientation + heading. I2C. Critical for attitude underwater (no GPS)
|
1 | $20 |
|
Depth Sensor — MS5837-30BA
Pressure-based depth. I2C. Gel-filled, designed for ROVs. 0–30m range
|
1 | $25 |
|
Water Temp — DS18B20 (waterproof)
Stainless probe. Useful data for fish behavior. OneWire bus
|
1 | $4 |
| Component | Qty | Est. |
|---|---|---|
|
Micro Servos — MG90S or equivalent
Dorsal fin rays (6–8 servos), pectoral fins (2 servos). Metal gear, waterproofed with silicone or conformal coat
|
10 | $30 |
|
Servo Driver — PCA9685
16-channel PWM via I2C. Drives all fin servos from one bus
|
1 | $6 |
|
Fin Material — Silicone / TPU Sheet
Flexible membrane connecting fin rays. Cut to profile, glue to servo horns
|
1 | $10 |
| Component | Qty | Est. |
|---|---|---|
|
Tendon Curl Servo — MG90S
Single servo at tail base. Pulls dual braided cables through spine channel to curl/uncurl tail. Fail-safe: power off = slack = release.
|
1 | $3 |
|
Tendon Cable — Braided Dyneema/Spectra
0.5mm braided line. Two runs (curl + uncurl) through tail spine channel. High strength, near-zero stretch.
|
2m | $4 |
|
Grip Pads — Ridged TPU
Textured inner surface on last 5–6 tail segments. Micro-ribbed for wet grip on wood, rock, coral.
|
1 set | $3 |
|
Contact Sensor — FSR (Force Sensing Resistor)
Tail tip. Detects contact with structure to trigger grip tightening. Analog input to Pi GPIO.
|
1 | $3 |
| Component | Qty | Est. |
|---|---|---|
|
Flexible Solar Cells — 5V 200mA panels
Thin-film flex cells on dorsal surface between fin rays. ~0.5–1W total in good sun at 1–2m depth. Wired to charge controller.
|
2–3 | $15 |
|
Micro Hydro Turbine — 20–30mm
Integrated in tail segment. Water funnels through tapered tail, spins turbine. ~100–200mW in 0.3+ m/s current. DC generator output.
|
1 | $12 |
|
MPPT Charge Controller (micro)
Manages solar + turbine input, trickle charges LiPo. BQ25570 or similar ultra-low-power harvester IC.
|
1 | $8 |
| Component | Qty | Est. |
|---|---|---|
|
2S LiPo Battery (7.4V, 2200mAh)
Compact, good energy density for servos + Pi
|
1 | $18 |
|
BEC — 5V 3A + 6V Servo Rail
Dual output: 5V for Pi, 6V for servo rail
|
1 | $8 |
|
Tether Cable — Cat5e or USB3 (thin)
30–50m. Ethernet for video stream + control. Routes through spine channel. Neutral buoyancy preferred.
|
1 | $25 |
| Component | Qty | Est. |
|---|---|---|
|
Acrylic Tube — 90mm OD × 300mm
Clear tube, end caps with o-ring seals. Houses Pi + battery + sensors. BlueRobotics or similar.
|
1 | $40 |
|
Cable Penetrators / Potted Bulkheads
Waterproof pass-throughs for camera ribbons, servo wires, tether. Epoxy-potted.
|
1 set | $20 |
|
Ballast Weights (lead/steel)
Adjustable trim. Different amounts for salt vs fresh. Velcro-mount to tube.
|
1 set | $10 |
ESTIMATED TOTAL — MVP 1 (core) |
~$357 | |
With energy harvesting (Scout+ tier) |
~$392 |
The Raspberry Pi 5 gives us dual CSI-2 for synchronized stereo capture, enough compute for real-time OpenCV depth mapping, and a full Linux stack for rapid iteration. No custom PCB needed for validation.
Side-mounted cameras mimic real seahorse eye placement. Each eye sits in a socket on the side of the head with a flat optical viewport. Angled slightly inward, their FOVs converge ahead of the ROV — giving excellent stereo depth resolution at exactly the 0.5–3m scouting range. The baseline is naturally set by the head width (widest segment). The 180° rotation enables three distinct vision modes: both inward (stereo depth), both outward (near-360° panoramic), or mixed (forward scout + rear awareness). Side eyes also read as prey to fish — less threatening than forward predator eyes.
The tether-first approach eliminates the hardest underwater problem — wireless comms. RF dies in water, acoustic is slow, optical is line-of-sight. A thin cable gives us full-bandwidth video + bidirectional control with zero latency. The tether runs through the spine channel, protected by the segmented body.
Undulating fin propulsion is silent and low-turbidity. Fish detect traditional thrusters through their lateral line organ from meters away. A wave-driven fin mimics natural fish movement and won't spook your targets.
Freshwater: Lower density (~1.0 g/cm³). ROV will be less buoyant — may need less ballast weight. No corrosion concern on most materials. Better visibility in lakes, worse in rivers with sediment.
Saltwater: Higher density (~1.025 g/cm³). More buoyant — add ballast to compensate. Corrosion on anything non-marine-grade. Use 316 SS or titanium fasteners, conformal coat all electronics, rinse after every use. Better visibility nearshore in calm conditions.
Ballast strategy: Adjustable ballast weights with Velcro mount for MVP 1. Swap weights when switching between salt and fresh. Future: active buoyancy engine (syringe pump) auto-compensates.
Inspired by McKittrick & Meyers' research at UC San Diego. The seahorse tail uses 36 square segments, each made of 4 L-shaped interlocking plates. The structure compresses to ~50% before permanent damage, protecting the spine. We apply the same principles to create a modular, impact-resistant, field-replaceable enclosure for the ROV electronics.
Ref: UCSD — Seahorse Armor Research · Acta Biomaterialia, 2013
The seahorse shape isn't cosmetic — it's functional camouflage. Side-mounted eyes are the key detail. Fish have evolved to recognize eye placement as friend-or-foe. Forward-facing eyes (cats, sharks, eagles) signal predator. Side-facing eyes (most fish, seahorses, herbivores) signal non-threat. By placing cameras on the sides of the head like a real seahorse, the ROV registers as fauna, not hunter. It gets closer to fish without triggering flight response — exactly what you need for a scouting tool.
The compact profile also means no protruding motor arms to snag on weeds, branches, or fishing line — common hazards in the exact structures where fish hold. And the smooth head dome with flush eye sockets cuts cleanly through water with minimal drag.
The combination of prehensile tail anchoring, solar harvesting, and water turbine generation fundamentally changes what this device is. It's not an ROV you use for 20 minutes. It's an autonomous underwater observation platform that can run for hours — potentially all day in the right conditions.
The key insight: anchored patrol mode draws dramatically less power than swimming. Propulsion is 60-70% of total energy budget. Eliminate it and you extend runtime 3-4x from battery alone. Add harvesting on top and the math gets very interesting.
6:00 AM — Deploy seahorse at a channel swing on a river. Thruster transit to submerged log jam 40m upstream. Tail anchors to a branch on the current-facing side.
6:05 AM–12:00 PM — Anchored patrol mode. Cameras at low frame rate duty cycle. Solar charging from morning sun. Turbine harvesting from river current. Logging water temp, depth, and video frames. When fish activity detected, switches to full-rate video and flags timestamp.
12:00 PM — Retrieve. You have 6 hours of data: fish activity heatmap (most active 7:15–8:30 AM), water temp curve (peaked at 18.2°C at 10 AM), and video clips of every fish that passed the structure. You now know exactly when and where to fish tomorrow.
No fish finder on the market provides this dataset.
WE ARE HERE