Automatic Baby Stroller Rocker

This is my first proper 3D printed project, an automatic baby stroller rocker designed to gently move the stroller back and forth so parents can take a short break.
It might not look perfect, but it works beautifully — and that’s what really matters!

The system is powered by a JGB37-550 DC motor (168:1), controlled through a HW-070 PWM module and a 3-cell 18650 battery pack with BMS  (for the battery I've used this project).
Mechanically, it uses two 608ZZ bearings, a threaded M8 rod with two M8 nuts, one square M3 nut (5.5 mm), M5x30 with nut, and a M3x20 screw.

The design includes:

• a main housing (connected with a dovetail joint),
• a motor arm with a bearing and square nut (to tighten to the motor shaft),
• two adapters for the M8 threaded rod (each fits into a bearing and have inserted nut),
• mounts with integrated bearings and knobs for attaching to the wheel,
• and two clips with dovetail for securing the system to the stroller frame also with screw and nut.

The PWM control makes the motor a bit noisy, but my son actually seems to enjoy the gentle humming sound — so I’ll count that as a feature 😄

Currently, the motor speed is used in the lower range of the PWM adjustment, so the 168:1 gearbox (≈86 RPM) is actually too fast for ideal motion.
A smaller gear ratio (around 30–40 RPM) would provide a smoother and more natural rocking movement.

🧩 Parts List — Automatic Baby Stroller Rocker

🧠 Electronics

• JGB37-550 DC motor, I've used 168:1 gearbox (≈86 RPM) but i suggest 30-40RPM
• HW-070 PWM speed controller
• 3 × 18650 Li-ion cells
• 3S BMS (Battery Management System) for the 18650 pack
• Wires

⚙️ Mechanical Components

• 2 × 608ZZ bearings (8 mm inner diameter, 22 mm outer diameter, 7 mm thick)
• 1 × Threaded rod M8 (length depends on your stroller setup, e.g. ~150–200 mm)
• 2 × M8 nuts (for securing the rod)
• 1 × Square M3 nut (5.5 mm width) — fits in the motor arm
• 1 × M3×20 mm screw (for fastening the motor arm)
• 2 × M5×30 mm screw + nut (for the stroller frame clamps)
• 6 x M3x12 mm screw to secure motor in the box
• 4 x M3x6 countersunk self tapping screw to secure 18650 holder to the box
• Some wires

NOTE:

• bearing adapter plate - pause on 70 layer to insert nut
• motor arm plate - pause on 40 layer to insert square nut