Video Summary - I'm building a Space Cadet Pinball Machine!

Summary of Technological Concepts / Product Features / Analysis

Project overview

The creator is building a real-life Space Cadet pinball machine, iterating on mechanisms from prior videos, including:

Pop bumpers
Slingshots
Drop targets
Mini pop bumpers
Ball drop
Flippers

Main issue: coil power + overheating risk (flippers)

Critique of the original flipper design

A prior critique (auto-generated) highlighted that the flippers used solenoids driven without a separate “low power hold coil”, unlike real pinball flipper mechanisms.

Why overheating matters

Because players can keep the flipper button pressed for long periods, holding full solenoid power can overheat the coil. The builder references a Technology Connections quote describing overheated coils melting/smoking.

Planned solenoid approach (and constraints)

They want to use frame-type solenoids, but availability is a concern globally. Those solenoids may require:

A custom shaft, or
A flipper rebuild kit

Technical workaround: PWM-based power reduction while holding (flippers)

Instead of switching directly to true dual-coil flippers, they test a control strategy:

Use a PWM power reduction approach
Drive via a MOSFET driver

Code behavior:

Solenoid at full power for ~0.5 seconds
Then reduce to ~20% power for the hold

Test outcomes:

Extended “hold open” produced minimal temperature increase
Under test conditions, a hard hit could cause the solenoid to snap back closed even while the button remained held
They believe there is still power headroom

Next step: Revisit behavior when larger solenoids arrive.

Flipper rubber/material tuning

Rubber choice

Their earlier TPU printed flipper rubber was too stiff. They switched to the correct-scale red silicone bands, which fit well.

Stronger flipper construction

They needed stronger parts to handle higher-force solenoids:

They can’t print strong nylon on their Creality Ender A1 due to lack of enclosure.
They use Formlabs Form 4 Tough 1500 resin, selected for toughness and flex without breaking.
Post-processing: 12-minute cure at 70°C

Durability test:

Ball shaft fixed in a vice
A ball is dropped from about 1.5 meters repeatedly (harder than real gameplay)
Tough 1500 survives and shows spring-like behavior

Large pop bumpers: mechanical travel and voltage adjustments

Root cause: insufficient solenoid travel

The bumpers underperformed because the solenoids have only ~9 mm of travel. Specifically:

If the outer ring starts too high, it doesn’t reach the ball far enough toward the center
That reduces leverage and performance

Mechanical fix

They lowered the ring, improving reliability in getting the ball off the ramp.

Voltage upgrade

Even with the fix, it was underpowered at 12V, so they tried 24V:

Result: major performance improvement

Ring durability improvements

Because bumper rings take heavy abuse, they plan to use metal rings:

1-mm stainless rings laser cut
A 3D printed forming tool (PLA, 100% infill) helps shape/press the mold
They note the required forming pressure is low

Testing confirms the metal ring works well.

Sponsor-supported manufacturing workflow (PCBWay)

PCBWay is used as a reference for ordering sheet metal parts:

Upload a 3D model or flat pattern
Choose quantity and material
For parts with folds/threads, provide a simple drawing
They can offer surface finishes (for bumper rings, stainless steel is the target)

Top playfield build: opto rollover switches + lighting

Switches and layout

The top section adds:

Three rollover switches with lane dividers and lights
A hidden arrow light near the top of the ramp

Lighting approach

Clear plastic components are printed with Formlabs Form 4
Use clear V5 resin for consistent tint
Simulate game states using brightness:
- low brightness when off
- high brightness when on
Hidden arrow achieved by:
- receding (rebating) the back of the ramp
- hiding lights behind remaining plastic to create diffusion

Opto rollover integration

Test thin opto switches to mount under the playfield while allowing the ball to pass
Print small white borders for aesthetics

Ball-actuated “cards”:

Printed in gray V5 resin because FDM fit was poor (very small parts)
Actuation uses:
- small springs from PS4 trigger springs
- springs held with an M2 bolt

Playfield dividers: acrylic laser cutting

For playfield borders:

Use acrylic
Cut with a Turbo 747 (OmTech) 70W CO2 laser
- thin acrylic cuts quickly (seconds per part)

Divider layering/colors:

Red acrylic top
White bottom

Additional covers for mini pop bumper backs:

black and white

Ball scaling + collision clearance

They found the divider gap wasn’t sufficient for their default ball size. After reconsidering earlier scaling decisions, they align with typical pinball ball sizes (commonly 27 mm).

To fit correctly, they switch to a 20 mm ball, which:

passes through the gap cleanly

They note some component heights will be adjusted later.

Ball return mechanism redesign (no room due to right-side kickback line)

Design goal

They can’t use a traditional ball return, so they emulate “ball appears from thin air” by pushing balls upward from below the playfield.

Mechanism overview

A solenoid-driven bracket pushes (not pulls) a pivoting arm under the playfield
The arm pivots up to spit the ball into the lane

Under-playfield logistics (with sensors)

A recessed drain at the bottom, covered with thin acrylic
Ball rolls down to a lower corner with LED + sensor pairs detecting presence
A solenoid fires the ball into a channel that:
- curves
- rises past the ball return area
The design prevents backward rolling

The lifter/channel includes holes for multiple sensor points so software can count balls ready.

Voltage/power testing

Solenoids run on 24V to move balls up a long distance successfully
Concern: power might fail when the table is angled
Larger solenoids arrived but weren’t faster, so they prefer increasing voltage

Voltage generation test:

Adapter using two drone batteries
Reaching about ~34V (near a 36V target)

Conclusion so far: Higher voltage helps ensure the ball reaches the top reliably.

Multiple-voltage strategy

They infer they may need different voltages for different mechanisms:

Some components (e.g., mini pop bumpers) are fine at 12V
At 36V, they’d be too intense due to limited local impact area

Kickback mechanism (and auto-launcher integration)

Why it stays similar

Kickbacks were originally like an auto launcher, so they keep the same general style for simplicity.

Build details

Kickback arms:
- laser cut 1-mm stainless, folded on etched lines
Mounted with a 3D printed bracket using a double-arm design

Shooter lane integration

Allows a mechanical plunger through the middle for the main shooter lane
Supports both auto-launch and manual start

Sensor integration

Adds a rollover switch built into the mechanism using:
- opto switches
- 0.4mm spring wire for light actuation

Power status

Tested at ~34V with “decent power”
Next they want a baseboard power test in another video

Slingshot tuning: rubber band selection + high voltage test

Their earlier slingshot rubber (an exercise band) didn’t satisfy viewers.

They receive correct replacement parts from Flippin’ A (Patrick), using silicone pinball bands in various sizes, specifically:

2.5 inch bands for slingshots

With correct rubber + higher voltage, slingshots perform “so much better.”

Wormholes: magnet-based capture/release for levels

Wormholes serve two purposes:

Regularly capture and spit the ball back out
On some levels, transport the ball between holes

Current prototype focus: capture + release

Housing contains two magnets that hold the ball
Includes an internal ramp to “suck” the ball inward
A solenoid + stainless arm fires the ball back out

They use the same LED/sensor concept as earlier ball return.

Note: They ordered proper IR LEDs/sensors, but they didn’t arrive in time.

Result: Magnets hold perfectly, and there’s enough power to fire it back out → “win.”

Future work: Try “transport between holes” by reworking ball-drop positioning for clearance.

Project management / file distribution

Viewers asked to pay for project files. The creator avoids paywalling fully but plans:

A Patreon where finalized parts’ files are released over time
Limited behind-the-scenes due to a full-time job (occasional clips/images)
Option to subscribe briefly (even 1 month) to download everything at the end

Key review / guide / tutorial takeaways

PWM coil holding is a practical alternative to dual-coil flipper solenoids for overheating safety.
Material selection + curing matter for durable moving parts:
- TPU can be flexible but too stiff
- Tough 1500 resin proved durable via repeated drop testing
Performance debugging using kinematics:
- Solenoid travel was too short (~9 mm), reducing ring leverage
- Fixes involved repositioning and voltage tuning
Power strategy across mechanisms:
- Use voltage scaling per mechanism rather than one global voltage
Ball transport design pattern:
- Use sensor-detected staged solenoid channels to move balls from drain to an elevator-like lifter
Under-playfield opto integration:
- Thin opto switches + printed blockers (“cards”) + small springs enable actuation while preserving ball clearance
Manufacturing suggestion:
- Use laser cutting for acrylic borders (fast)
- Use laser cut stainless for high-abuse rings

Main speakers / sources (end)

Main speaker: The video creator (first-person builder of the pinball machine)
Quoted source: Technology Connections (coil overheating safety discussion)
Referenced contributors/suppliers:
- Patrick / Flippin’ A (silicone pinball rubber bands)
- PCBWay (manufacturing sponsor/workflow)
- Formlabs (Form 4 / Tough 1500 resin)
- OmTech (Turbo 747 laser)