Smart Espresso Scale
Worked for 2 mins 29 sec
Created 5 project docs
Firmware Starter — ESP32-S3 Smart Espresso Scale
MCU: ESP32-S3-WROOM-1-N8R8 (U4) Framework: Arduino on PlatformIO
Board Bring-Up Plan — Smart Espresso Scale
Equipment: current-limited USB supply, multimeter, oscilloscope, USB-C cable, known calibration weights, Li-ion cell simulator or protected ...
Technical Construction File — Smart Espresso Scale
Draft FCC Part 15 intentional radiator / modular transmitter integration review
Safety Analysis — Smart Espresso Scale
Draft Low-voltage, USB-C powered, single-cell Li-ion battery product. No mains voltage is present on the PCB.
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Designed the smart espresso scale schematic and renamed the project Smart Espresso Scale. The schematic now has 55 components / 44 nets, including USB-C power/ESD, BQ24295 Li-ion charger/power-path, 3.3 V regulation, ESP32-S3 BLE MCU, NAU7802 load-cell AFE, microSD logging, I2C OLED display, buttons, and status LEDs; verification found no open ERC/component/footprint errors in the checked categories.
Project files created:
- Project Specification
- Block Diagram
- Reference Recreation Ledger
- Power Budget
- Firmware Starter
- Board Bring-Up Plan
- Technical Construction File
- Safety Analysis
- Preliminary FMEA
Open items:
- Select the final Li-ion cell capacity and set BQ24295 charge current accordingly; firmware currently notes a conservative ≤512 mA target.
- Validate TLV1117 dropout/thermal margin during BLE + display + SD write bursts.
- Verify the exact OLED/display module pinout and 3.3 V compatibility before production.
- PCB layout still needs antenna keepout, charger/regulator thermal layout, and load-cell analog routing care.
Suggested next steps:
- Proceed to PCB board size/constraints and component placement.
- Choose the final battery capacity and enclosure/display mechanical constraints.
- Run PCB layout with ESP32 antenna keepout and load-cell analog separation.
- After placement, route and run full DRC/PI/SI checks.
Layout and fix risks
Proceed to layout
Fix open risks
Set design constraints
Run schematic review
Refine this doc
Ask about this doc
Preliminary FMEA — Smart Espresso Scale
Scope
Design-stage FMEA for a USB-C rechargeable BLE espresso scale with Li-ion battery, load-cell ADC, display, and microSD logging.
Table
| Subsystem | Failure Mode | Effect | Severity | Likelihood | Detection | RPN | Mitigation |
|---|---|---|---|---|---|---|---|
| Battery charging | Charge current too high for selected cell | Cell heating, reduced life, safety risk | 8 | 4 | 4 | 128 | Select final cell, set BQ24295 charge current <= cell rating, validate temperature |
| 3.3 V regulator | Thermal shutdown under BLE+SD bursts | Resets, data loss | 5 | 4 | 3 | 60 | Thermal test; consider buck or lower-dropout regulator if needed |
| Load cell input | Noise/poor grounding | Unstable readings | 4 | 5 | 4 | 80 | Preserve AFE filtering, quiet analog routing, calibrate in firmware |
| microSD | Removal during write | Corrupt log file | 3 | 5 | 4 | 60 | Detect card, flush writes, UI logging indicator |
| USB-C input | ESD event | MCU/charger damage | 6 | 3 | 5 | 90 | Keep ESD device near connector, short return path, verify DRC/layout |
| BLE/RF | Antenna keepout violation | Poor range/non-compliance | 5 | 4 | 4 | 80 | Enforce module antenna keepout in placement/layout |
| Display | Wrong module pin order/voltage | No display or damaged module | 3 | 3 | 3 | 27 | Verify exact DS1 module footprint/pinout before production |
| Firmware | No tare/calibration persistence | Inaccurate measurements after reset | 3 | 4 | 2 | 24 | Store calibration in NVS and include calibration workflow |
Highest-Priority Actions
- Select the final battery and set validated BQ24295 charge current.
- Run regulator thermal validation with BLE advertising, display on, and SD write bursts.
- Preserve antenna keepout and ESD placement during PCB layout.
- Verify display module pinout before layout release.
Scope
Highest-Priority Actions
