: inflatable infant prosthesis design

'Muscle sensor movement Robotics used to control:

a system of valves and air pump in an inflatable working against a spring inside a prosthetic hand,

designed for a baby or small children suffering this sad loss.

Arduino Baby Prosthetics Crew on Facebook

Researching the design of robotic hands that are controlled by the muscle movements form the residual limb of individuals who have experienced limb loss.

By using muscle movement sensors attached to the patient's residual limb, it's possible to control the movement of the robotic hand.

We are dedicated to our ongoing research, to be developed over time.

AI ChatGPT to generate diagrams, and the gorgeous 3D images, on the site. Also, for obtaining Arduino code, for controlling the robotic systems,

and onshape free cad for inner mechanical design and creating 3D print designs (.stl files).

‘Relying on the nature of how air pressure works in a controlled pre-filled air inflatable,

against a small amount of spring tension at each joint, enough for a baby or small child.’

Two arm Prosthesis: With controller worn in persons external clothes pocket. A simple power connection to the 'Harness/Torso Suit'.

+ Big Thanks to: Chat GPT [AI] and Onshape [free CAD] and Arduino [microcontroller] and Elegoo [Starter kit] +

Traditional Prosthesis design

Inflatable infant prosthesis design -

using; Arduino R3 controlled system of valves,

and a small charge of ambient air. Much more beautiful and soon tweaked and ready for 3D print.

The 'Harness/Torso' Designs

Thingiverse - Digital Designs for Physical ObjectsDownload millions of 3D models and files for your 3D printer, laser cutter, or CNC. From custom parts to unique designs, you can find them on Thingive

2yr Child hand STL - tripo - orig.stl

The inflatable knuckle

[which will be the most used knuckle joint in this Air powered design]

1st finger knuckle - fully inflated [finger in a fist position]

1st finger knuckle - partially inflated

[in a straight finger position]

The inner finger assembly:

This video shows the inner workings of a design for an air/pump/arduino/3d printable 2 yr old child prosthesis knuckle joint.

There will be 4 to 5 knuckle arcs in the final version, this is just a prototype [for a finger with 10mm Diameter].

Within the frame, there will be [see below] a very small inflatable, like a pea which expands to the size of a of a small arc shaped lozenge.

This inflation produces rotation in one on the side plates, one plate will act as if fixed [to the rest of the body.

A 97.5° angle of rotation is required.

The images below, were made using Chat GPT, they are based on a 2 year old child's hand. I have zoomed in quit a lot on these images, so you can see the detail

Use the below images, to make 3D printable STL files, of hands and feet, for realistic prosthetic development work, SEE HERE:

studio.tripo3d.ai

Gorgeous renders of the outside of the 2yr Childs hands and feet:

Colour 2yr Child feet L +R all views.7z

The FULL Baby Glove Guide [so far]

glove best?

Sonic 8K S resin printer:

Use the above images, to make 3D printable STL files, of hands and feet, for realistic prosthetic development work, SEE HERE:

studio.tripo3d.ai

Once you have the 3D STL file, use this in a high quality resin printer, to make the outer design of the prosthetic look super realistic.

I will be using the:

Phrozen Sonic Mini 8K S 7.1" LCD 3D Printer

https://www.3dprintmonkey.co.uk/products/phrozen-sonic-mini-8k-s-3d-printer

Phrozen High-Resolution Aqua 8K Resin

Phrozen Aqua 8K 3D Printer Resin – Phrozen EU

See the fine detail, in the high quality resin prints below

The 3D print quality available on the Sonic 8K S

The inside basics + Shoulder Socket Designs

Trying to make, an Arduino-controlled, on/off valve system, that allows the flow of ambient air, from one inflatable chamber into another and then back and forth.

For use or to make the rotations needed, from the inside of an infant prosthetic arm and hand.

A system which requires a small top-up of air from time to time. See initial designs below:

The Arduino R3 and valve electronics:

Ambient → Pump → Check Valve → Pressure Relief Valve (25 PSI)

↓

Manual Ball Valve ───────────────────────────────┐

↓

[Main Supply Line]

├──→ Air Reservoir

├──→ Solenoid Valve → Index Inflatable → Exhaust

├──→ Solenoid Valve → 2nd Inflatable → Exhaust

├──→ Solenoid Valve → 3rd Inflatable → Exhaust

└──→ Solenoid Valve → 4th Inflatable → Exhaust

Ambient → Manual Button Valve → Thumb Inflatable → Ambient

🌟 A New Vision for Child Prosthetics 🌟

Testimony

One day, the prosthetics industry will finally embrace a truly child-centered vision — one that values cuteness, comfort, and emotional connection, alongside precision mechanics, Arduino control, and beautifully engineered STL prints. Prosthetics should be life-like, expressive, and joyful.

Imagine:

🖐️ A soft, lightweight, realistic hand — sized for a toddler or child — that’s as friendly to wear as a glove.

⌚ An Arduino control unit worn like a stylish smartwatch, with a touchscreen interface a child can learn to love.

🧠 Tactile sensors embedded in each fingertip, providing real-time feedback on pressure, grip, and even texture — so the child doesn’t just move the hand…
they feel with it.

⚡ And soon — with EEG brainwave integration — the possibility of controlling the hand just by thinking, making the system not only intuitive, but revolutionary.

What the future won't be:

✘ Oversized or clinical
✘ Mechanical-looking
✘ Scaled-down adult tools

What the future can be:

✔ Emotionally engaging and beautiful
✔ Lightweight and sensor-smart
✔ Capable of intuitive control — even by thought

This hand responds to movement from tiny pneumatic inflatables powered by Arduino logic, but it can also adapt in real-time

— giving the child a true sense of touch and, eventually, mind-driven movement.

You’re not just building a prosthetic…

You’re designing a childhood companion:

✔ Beautiful
✔ Capable of movement, feeling — and thought
✔ Created with dignity, joy, and imagination

Let’s finish this first hand — and shape the next, together.

Final Table of Valves for 3D Printing (.STL)

Valve Type

Used For

Quantity

Key Specs

Check Valve

Between pump and main supply line

1.5 mm tubing, 2.5 mm ball, 0.75 mm spring, 2 mm wall

Pressure Relief Valve

Limits pressure (~25 PSI)

Adjustable spring preload, 1.5 mm vent hole, vents to ambient

Manual Ball Valve

Controls filling to the reservoir

Simple 90° turn, tight seal with 1.5 mm ports

Solenoid Valves

Index, 2nd, 3rd, 4th inflatables (electrically controlled)

3-way (P→A, A→Exhaust), 1.5 mm tubing, mini format

Manual Button Valve

Thumb inflatable only

Push-button, spring return, for momentary air delivery

📏 Valve Design Specs (Standardized)

Air Port Diameter: 1.5 mm
Wall Thickness: 2.0 mm minimum
Ball Diameter (Check Valve): 2.5 mm
Spring Diameter: 0.75 mm

idea for 3 finger stumps Prosthesis:

System Architecture (Straightforward + Efficient)

(with actuator-as-button pop-up motion)

🧠 Inputs:

1 IMU per finger stump (e.g. MPU6050, mounted near the natural knuckle) This detects the horizon line.
Arduino Nano reads the pitch angle from each IMU

🧠 Logic Flow:

User flexes finger stump (rotates pitch downward)
IMU detects the pitch change
Nano activates a tiny actuator that behaves like a button pop-up
- This actuator produces ~10 mm of linear motion upward
- Could be a mini solenoid, SMA wire, or pneumatic puffer
That button-like movement pushes a micro lever
Lever rotates the proximal hinge joint of the prosthetic finger
Distal (tip) joint is passively linked — it follows the first joint’s rotation