Development / HydroHalo MK.1
Iteration 1 · First prototype · Built & tested
HydroHalo  ·  MK.1

A motor, a battery,
and a cable.

MK.1 is the first prototype — built to prove the concept. A brushless motor turns a custom-welded spool that lets out (or reels in) a rubber-coated cable attached to a belt on the swimmer. One of the team operates the throttle by hand; the other swims. The whole unit grips the pool deck with a single industrial suction cup.

2000WBrushless drive
48VDC supply
24hRuntime / charge
System block diagram ↓
HydroHalo MK.1 unit — black cylindrical housing with a cyan-lit cable port
01  ·  Architecture

System Block Diagram

Power flows from battery to motor to spool to cable to swimmer. An operator controls motor speed by hand — MK.1 has no microcontroller or app. Tap any block to see what it is.

OPERATOR · MANUAL THROTTLE Battery 48 V · 10 Ah Li-ion Powers motor directly Motor Vevor · 2000 W BLDC Operator-throttled Spool Welded aluminum Direct-drive shaft Cable Rubber-coated steel Negligible stretch Swimmer Padded belt Resistance load Grabo Nemo Industrial suction cup 48 V DC torque force anchors
Tap a block

Hover or tap any component above

Each block expands here with the technical role, what it's made from, and what it talks to.

    02  ·  MK.1 Targets

    Engineering Targets

    The numbers we built MK.1 against.

    0
    Total weight
    Portable. One person mounts it on any pool wall in under a minute.
    0
    Target price
    5× cheaper than the incumbent Power Tower ($3,000+).
    0
    Motor power
    Brushless DC. Smooth, silent, sealed against splash.
    0
    Battery runtime
    48 V × 10 Ah. A full day of training between charges.
    03  ·  Components

    Inside the Box

    Off-the-shelf where it works, custom fab where it matters.

    Grabo Nemo suction system

    Suction Mount

    Grabo Nemo · industrial vacuum cup. Holds the device flat against tile or concrete pool walls.

    2000W brushless motor

    Brushless Motor

    Vevor 48 V · 2000 W brushless DC. In MK.1 the throttle is operated by hand — no microcontroller, no closed-loop control.

    48V Li-ion battery pack

    Battery Pack

    48 V · 10 Ah Li-ion. Wired straight to the motor through the operator's throttle.

    Custom-welded spool

    Spool & Cable

    Custom-welded aluminum spool spinning on the motor shaft, wound with rubber-coated stainless cable. Low elongation, no skin irritation.

    04  ·  Comparison

    Vs. Existing Hardware

    The dominant pool resistance trainer is the "Power Tower" — a $3,000+ deck-bolted unit with a fixed weight stack and a nylon rope. Here is the gap.

    Power Tower Power Tower
    • Fixed weight stack — single force, no profile
    • ~50 lb, deck-bolted, not portable
    • Nylon rope — chafes skin under tension
    • $3,000+
    • No programmability, no telemetry
    HydroHalo MK.1 HydroHalo MK.1
    • Variable force — operator dials motor throttle up or down
    • <25 lb, suction-mount, two-minute setup
    • Rubber-coated steel cable + padded belt
    • ~$600 in parts (MK.1)
    • Programmable force profiles & app control (planned for MK.2)
    05  ·  Validation

    Testing

    Shop-bench validation of the drivetrain, then in-water trials at SDSU Crothers Hall.

    Shop bench

    Bench · Jacob
    Bench · Nik

    In-water

    Pool · Luke
    Pool · Jacob
    Pool · Nik