Hobby Electret Microphone Preamplifier for Nature Recording
Budget: €250 – €750 EUR
Design a compact integrated microphone preamplifier and phantom power circuit board for continuous 24/7 outdoor nature sound recording. The complete system will connect a PUI Audio AOM5024 electret microphone capsule to standard audio equipment using an on-board XLR connector and phantom power.
Technical Requirements
Microphone Specifications
Microphone Capsule: PUI Audio AOM5024 electret capsule (2-pin configuration)
Frequency Response: Flat response from 20Hz to at least 15kHz
Signal Quality: Good signal-to-noise ratio for nature sound recording
Power Requirements
Input Power: Standard 48V phantom power (P48)
Voltage Regulation: Stable voltage supply to the capsule
Power Filtering: Clean power with minimal noise
Audio Performance
Output: Low impedance output suitable for driving long cables
Balanced Output: Proper balanced signal for noise rejection
Cable Support
Cable Length: Must work well with XLR cable lengths of 20-50 meters
Cable Compatibility: Circuit should handle the capacitance of long cables
RF Protection
RF Immunity: Basic filtering to prevent radio frequency interference
EMI Protection: Protection against electromagnetic interference
Static Protection: Simple ESD protection for the microphone circuit
Environmental Durability
Operating Temperature Range: -20°C to +50°C (-4°F to 122°F) to handle various outdoor conditions
Humidity Resistance: Circuit must function reliably in high humidity environments
Condensation Protection: Design should minimize issues from daily temperature cycling
Long-term Reliability: Components selected for 24/7 continuous operation
Sizing and Housing
PCB should be of reasonable size and dimensions to fit in a custom 3D printable housing
Circuit board layout should consider mounting points for housing attachment
Design should accommodate weatherproofing measures
Component Selection
Design should utilize SMD components for compact size and improved performance
Include on-board XLR connector (through-hole recommended for mechanical strength)
Components should be selected for low noise performance suitable for audio applications
All components should have appropriate temperature and environmental ratings for outdoor use
Design should include provisions for conformal coating application
Deliverables
Circuit Design
Schematic diagrams (PDF and editable format)
PCB design files (Gerber files and editable source files)
Bill of Materials with component specifications
Assembly instructions including recommendations for conformal coating
Documentation:
Brief performance expectations document
Assembly guide for the complete microphone system
Recommendations for weatherproofing and environmental protection
Intellectual Property and Attribution
Open Source Agreement: All design documents, schematics, PCB files, and related materials will be released as open source. The freelancer must agree to these terms as a condition of the project.
Attribution: The freelancer will receive full and prominent credit for their work in all distributions of the design. This includes credit in documentation, repositories, and any future publications related to the project.
License: The project will be released under an open source hardware license (specific license to be discussed, such as CERN OHL, TAPR, or similar).
Candidate Requirements
Basic understanding of audio circuits
Experience with preamplifier design
Familiarity with balanced audio and phantom power
Knowledge of PCB design and layout
Experience with designs for outdoor/environmental exposure is a plus
Additional Notes
This is a hobby project for continuous outdoor nature recording. The design should focus on achieving good sound quality while ensuring long-term reliability in outdoor conditions. The PCB should be manufacturable by services like PCBWay or similar. While professional-grade performance is not required, the microphone should deliver clean audio with minimal noise and a flat frequency response as specified, while withstanding outdoor environmental conditions.
Budget and timeline are flexible for the right design solution.
Technical Requirements
Microphone Specifications
Microphone Capsule: PUI Audio AOM5024 electret capsule (2-pin configuration)
Frequency Response: Flat response from 20Hz to at least 15kHz
Signal Quality: Good signal-to-noise ratio for nature sound recording
Power Requirements
Input Power: Standard 48V phantom power (P48)
Voltage Regulation: Stable voltage supply to the capsule
Power Filtering: Clean power with minimal noise
Audio Performance
Output: Low impedance output suitable for driving long cables
Balanced Output: Proper balanced signal for noise rejection
Cable Support
Cable Length: Must work well with XLR cable lengths of 20-50 meters
Cable Compatibility: Circuit should handle the capacitance of long cables
RF Protection
RF Immunity: Basic filtering to prevent radio frequency interference
EMI Protection: Protection against electromagnetic interference
Static Protection: Simple ESD protection for the microphone circuit
Environmental Durability
Operating Temperature Range: -20°C to +50°C (-4°F to 122°F) to handle various outdoor conditions
Humidity Resistance: Circuit must function reliably in high humidity environments
Condensation Protection: Design should minimize issues from daily temperature cycling
Long-term Reliability: Components selected for 24/7 continuous operation
Sizing and Housing
PCB should be of reasonable size and dimensions to fit in a custom 3D printable housing
Circuit board layout should consider mounting points for housing attachment
Design should accommodate weatherproofing measures
Component Selection
Design should utilize SMD components for compact size and improved performance
Include on-board XLR connector (through-hole recommended for mechanical strength)
Components should be selected for low noise performance suitable for audio applications
All components should have appropriate temperature and environmental ratings for outdoor use
Design should include provisions for conformal coating application
Deliverables
Circuit Design
Schematic diagrams (PDF and editable format)
PCB design files (Gerber files and editable source files)
Bill of Materials with component specifications
Assembly instructions including recommendations for conformal coating
Documentation:
Brief performance expectations document
Assembly guide for the complete microphone system
Recommendations for weatherproofing and environmental protection
Intellectual Property and Attribution
Open Source Agreement: All design documents, schematics, PCB files, and related materials will be released as open source. The freelancer must agree to these terms as a condition of the project.
Attribution: The freelancer will receive full and prominent credit for their work in all distributions of the design. This includes credit in documentation, repositories, and any future publications related to the project.
License: The project will be released under an open source hardware license (specific license to be discussed, such as CERN OHL, TAPR, or similar).
Candidate Requirements
Basic understanding of audio circuits
Experience with preamplifier design
Familiarity with balanced audio and phantom power
Knowledge of PCB design and layout
Experience with designs for outdoor/environmental exposure is a plus
Additional Notes
This is a hobby project for continuous outdoor nature recording. The design should focus on achieving good sound quality while ensuring long-term reliability in outdoor conditions. The PCB should be manufacturable by services like PCBWay or similar. While professional-grade performance is not required, the microphone should deliver clean audio with minimal noise and a flat frequency response as specified, while withstanding outdoor environmental conditions.
Budget and timeline are flexible for the right design solution.