HARDWARE INTEROPERABILITY STANDARD

Version 1.0 | November 2025 | Public Domain

Executive Summary

This document establishes open, non-proprietary hardware standards for countertop food synthesizers to prevent vendor lock-in, proprietary cartridge systems, and DRM-based enclosure. These specifications ensure universal compatibility across manufacturers and protect the open-source nature of personal food production.

1. Mechanical Interface Standards

1.1 Universal Cartridge Interface

Physical Dimensions:

· Form Factor: Standardized 100mm × 60mm × 25mm (L×W×H)
· Material: Food-grade PETG or polypropylene
· Weight Limit: 500g maximum payload

Connection System:

```
Primary Fluid Port: 4mm quick-connect (food-grade)
Secondary Fluid Port: 2mm quick-connect (additive line)
Electrical Interface: 6-pin magnetic data/power connector
Mechanical Lock: Spring-loaded latch with optical position verification
```

1.2 Synthesis Chamber Interface

Build Volume Standard:

· Minimum Volume: 150mm × 150mm × 100mm (X×Y×Z)
· Heated Bed: Standard 24V DC, 200W maximum
· Temperature Range: Ambient to 120°C

Motion System:

· Axis Standard: CoreXY or Cartesian with open specifications
· Positioning Accuracy: ±0.1mm minimum
· Repeatability: ±0.05mm across build volume

2. Electrical & Data Standards

2.1 Power Distribution

Main System Power:

· Voltage: 24V DC nominal
· Connector: XT60 standard
· Maximum Current: 10A continuous

Cartridge Power:

· Voltage: 5V DC / 12V DC selectable
· Current Limit: 2A maximum per cartridge
· Protection: Reverse polarity, over-current, short-circuit

2.2 Communication Protocol

Open Synthesis Bus (OSB):

```
Physical Layer: I2C at 100kHz
Address Space: 8-bit (0x08 to 0x77)
Packet Structure: [Header][Command][Data][CRC]
Error Handling: Automatic retry, checksum verification
```

Standard Commands:

· 0x10 - Cartridge Identification
· 0x20 - Status Request
· 0x30 - Begin Dispensing
· 0x40 - Emergency Stop
· 0x50 - Firmware Update

3. Fluid Handling Standards

3.1 Pump & Valve Specifications

Peristaltic Pump Standard:

· Flow Rate: 0.1-10 mL/min adjustable
· Accuracy: ±2% of setpoint
· Material: Food-grade silicone tubing (3mm ID)

Solenoid Valve:

· Response Time: <50ms
· Pressure Rating: 0-30 PSI
· Leak Rate: <1 droplet per hour at max pressure

3.2 Fluid Path Safety

Multi-Layer Protection:

```
Primary: Optical fluid detection
Secondary: Pressure monitoring
Tertiary: Flow rate verification
Emergency: Thermal runaway protection
```

4. Safety & Verification Systems

4.1 Hardware Safety Interlocks

Required Safety Circuits:

· Door-open detection (optical + mechanical)
· Over-temperature shutdown (dual sensors)
· Fluid leak detection (conductivity sensors)
· Motion boundary limits (endstop + software)

4.2 Quality Verification

In-Line Sensors:

· pH Monitoring: 2.0-10.0 range
· Conductivity: 0-100 mS/cm
· Turbidity: 0-1000 NTU
· Temperature: -10°C to 150°C

5. Anti-Enclosure Provisions

5.1 DRM Prevention

Explicitly Banned Practices:

· Proprietary authentication chips
· Encrypted communication protocols
· Cartridge usage counters
· Region-locking of components

Required Open Alternatives:

```
Identification: Open UUID standard
Authentication: Public-key cryptography (open keys)
Verification: Checksum-based integrity checking
```

5.2 Universal Compatibility

Mandatory Interoperability:

· All cartridges must function in all compliant synthesizers
· No manufacturer-specific "features" that break compatibility
· Open firmware updates available for all components

5.3 Repair & Modification Rights

User-Guaranteed Rights:

· Right to repair all components
· Right to modify firmware
· Right to manufacture replacement parts
· Right to interface third-party components

5.4 Patent Resistance Certification
Any device implementing this standard may display the "OHS-PRC Certified" (Open Hardware Synthesizer - Patent Resistant Certified) mark, indicating it is designed to be legally immune to the following specific patent threats:

· Immunity to Cartridge DRM Patents: Compliance with Section 5.1 (DRM Prevention) provides a legal design-around for patents held by entities like PepsiCo on proprietary cartridge authentication (referencing patent classes 700/300, 426/231).
· Immunity to Interface Patents: The universal mechanical interface (Section 1.1) creates prior art for any proprietary physical cartridge design.
· Legal Defense Fund: The Open Hand Society maintains a legal fund to defend any certified manufacturer against patent infringement claims, provided they adhere strictly to this standard.

6. Certification & Compliance

6.1 Open Hardware Certification

"OHS Certified" (Open Hardware Synthesizer)

· Must implement all required interfaces
· No proprietary extensions that break compatibility
· Full documentation available
· Open-source firmware required

6.2 Testing & Validation

Compliance Testing Suite:

· Mechanical interface verification
· Electrical compatibility testing
· Communication protocol validation
· Safety system verification

7. Implementation Specifications

7.1 Reference Designs

Available Reference Implementations:

· Open-source CAD models for all mechanical parts
· Circuit schematics and PCB layouts
· Firmware reference implementation
· Bill of materials with multiple sourcing options

7.2 Manufacturing Standards

Tolerances:

· Mechanical: ±0.1mm
· Electrical: ±5% component values
· Fluidics: ±2% flow rate accuracy

8. Corporate Strategy Countermeasures

Explicit prevention of known enclosure tactics:

Against "Cartridge DRM" Strategy:

· Standardized mechanical interfaces prevent proprietary designs
· Open communication protocol prevents authentication locking
· Multiple sourcing requirements prevent single-supplier dependency

Against "Parts Monopoly" Strategy:

· Standardized components available from multiple suppliers
· Open CAD models enable third-party manufacturing
· No proprietary fasteners or specialized tools required

Against "Firmware Lock-in" Strategy:

· Open-source firmware reference implementation
· Standardized bootloader for easy updates
· No encrypted or signed firmware requirements

Legal Notice

This document and all specifications herein are dedicated to the public domain under CC0 1.0 Universal and protected under the Open Hardware License. Any attempts to patent, copyright, or restrict implementation of these standards will be considered a violation of open-source principles.

Manufacturers implementing these standards must agree to:

· Never implement DRM or usage restrictions
· Provide full documentation to users
· Allow third-party repair and modification
· Contribute improvements back to the open standard
