Embedded hardware engineer — SPL meter prototype (schematic + PCB layout) Ended

About the job

Project summary

I need a schematic and PCB layout done for a small handheld sound pressure level (SPL) meter — a single-board device with a calibrated MEMS microphone, an ESP32-S3 MCU, a 3" SPI TFT display, a single button, and USB-C for power only (no battery). Full design intent, block diagram, BOM, connection list, calibration approach, and firmware architecture are documented in the attached build document — please review it before bidding.

Scope of work
Schematic capture from the attached BOM and connection list
PCB layout (2-4 layer, your recommendation) with attention to:
Low-noise routing for the microphone's analog rail, physically separated from the switching regulator
Clean digital routing for SPI display, I2S microphone, USB-C, and button
Output deliverables: schematic PDF, Gerbers, drill files, BOM with sourced part numbers, pick-and-place file
Not in scope (unless you'd like to quote separately): firmware development, enclosure design, PCB assembly/fabrication (I'll send your output files to JLCPCB or PCBWay myself)
What I'll provide
Full build document (block diagram, BOM with example part numbers, schematic-level connection list, power design notes, calibration procedure, firmware architecture/pseudocode)
Prompt answers to any design questions during the engagement
Requirements
Prior experience with ESP32/ESP32-S3 based designs
Prior experience with analog sensor front-ends (microphone, ADC, or similar low-noise circuitry) — this is the part... read more
Project summary

I need a schematic and PCB layout done for a small handheld sound pressure level (SPL) meter — a single-board device with a calibrated MEMS microphone, an ESP32-S3 MCU, a 3" SPI TFT display, a single button, and USB-C for power only (no battery). Full design intent, block diagram, BOM, connection list, calibration approach, and firmware architecture are documented in the attached build document — please review it before bidding.

Scope of work
Schematic capture from the attached BOM and connection list
PCB layout (2-4 layer, your recommendation) with attention to:
Low-noise routing for the microphone's analog rail, physically separated from the switching regulator
Clean digital routing for SPI display, I2S microphone, USB-C, and button
Output deliverables: schematic PDF, Gerbers, drill files, BOM with sourced part numbers, pick-and-place file
Not in scope (unless you'd like to quote separately): firmware development, enclosure design, PCB assembly/fabrication (I'll send your output files to JLCPCB or PCBWay myself)
What I'll provide
Full build document (block diagram, BOM with example part numbers, schematic-level connection list, power design notes, calibration procedure, firmware architecture/pseudocode)
Prompt answers to any design questions during the engagement
Requirements
Prior experience with ESP32/ESP32-S3 based designs
Prior experience with analog sensor front-ends (microphone, ADC, or similar low-noise circuitry) — this is the part of the design most sensitive to layout quality
Comfortable working from a written spec rather than needing it re-explained
To apply, please include
2-3 examples of past projects that included an analog sensor front end (not just general ESP32/MCU work)
One sentence on anything you'd change about the mic-rail/regulator separation described in the power design section of the attached document
A fixed-bid quote for schematic + layout + Gerbers/BOM/pick-place output, and your estimated turnaround time
Budget

Open to fixed-bid or hourly; happy to discuss based on your quote and experience level. read less
Project summary

I need a schematic and PCB layout done for a small handheld sound pressure level (SPL) meter — a single-board device with a calibrated MEMS microphone, an ESP32-S3 MCU, a 3" SPI TFT display, a single button, and USB-C for power only (no battery). Full design intent, block diagram, BOM, connection list, calibration approach, and firmware architecture are documented in the attache... read more
Project summary

I need a schematic and PCB layout done for a small handheld sound pressure level (SPL) meter — a single-board device with a calibrated MEMS microphone, an ESP32-S3 MCU, a 3" SPI TFT display, a single button, and USB-C for power only (no battery). Full design intent, block diagram, BOM, connection list, calibration approach, and firmware architecture are documented in the attached build document — please review it before bidding.

Scope of work
Schematic capture from the attached BOM and connection list
PCB layout (2-4 layer, your recommendation) with attention to:
Low-noise routing for the microphone's analog rail, physically separated from the switching regulator
Clean digital routing for SPI display, I2S microphone, USB-C, and button
Output deliverables: schematic PDF, Gerbers, drill files, BOM with sourced part numbers, pick-and-place file
Not in scope (unless you'd like to quote separately): firmware development, enclosure design, PCB assembly/fabrication (I'll send your output files to JLCPCB or PCBWay myself)
What I'll provide
Full build document (block diagram, BOM with example part numbers, schematic-level connection list, power design notes, calibration procedure, firmware architecture/pseudocode)
Prompt answers to any design questions during the engagement
Requirements
Prior experience with ESP32/ESP32-S3 based designs
Prior experience with analog sensor front-ends (microphone, ADC, or similar low-noise circuitry) — this is the part of the design most sensitive to layout quality
Comfortable working from a written spec rather than needing it re-explained
To apply, please include
2-3 examples of past projects that included an analog sensor front end (not just general ESP32/MCU work)
One sentence on anything you'd change about the mic-rail/regulator separation described in the power design section of the attached document
A fixed-bid quote for schematic + layout + Gerbers/BOM/pick-place output, and your estimated turnaround time
Budget

Open to fixed-bid or hourly; happy to discuss based on your quote and experience level. read less
Portable_SPL_Monitor_Build_Doc.md md Aug 05, 2026

Things to know

Job location

Remote

Work location

Job skill level

Any

Skill Level

Job rate

Open budget

Fixed-rate

Job type

Part-time

Job type

Job length

Under 1-month

Job duration

Areas of expertise

Analog Electronics Design BOM (Bill of Materials) Electrical Engineering Prototyping Schematic Design +2 more

Job categories

Prototype Design Engineering Electronic Prototyping and Design Services 3D Design Services

About the client

Payment not ready

Australia (04:18 pm)

Posted

Active

Job activity

25 Applicants

0 interviews in progress

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