Project Review and Updates
Worked for 1 min
The board is now a 68.6 × 53.4 mm, 2-layer Arduino-shield-sized layout; the exact Uno notch outline needs a later mechanical refinement, but placement can start safely within the standard envelope.
Worked for 8 mins 27 sec
I started the PCB layout for the C4 Smart Scale Carrier Rev A.
Accomplished:
- Set a 68.6 × 53.4 mm, 2-layer Arduino Uno shield-sized board.
- Placed all 29 physical components on the top side: Arduino shield headers, RS485/load-cell connectors, display/button connectors, buttons, LEDs, protection parts, and test points.
- Adjusted the RS485 protection cluster to reduce crowding near the load-cell connector.
Open items:
- The board outline is currently a rounded rectangle; the exact Arduino Uno notch/contour still needs mechanical refinement.
- Routing has not started.
- Auto-route is blocked by six internal Terminal objects still marked as auto-positioned; these need cleanup before routing.
- Execution is currently stopped because there are no available ACUs.
Suggested next steps once ACUs are available:
- Fix the remaining auto-positioned Terminal issue.
- Re-run the pre-route check.
- Route the 2-layer PCB.
- Add final silkscreen labels and Arduino shield mechanical details.
Fix terminals and outline
Fix Terminal issue
Refine Uno outline
Run DRC check
Add silkscreen labels
Refine this doc
Ask about this doc
C4 Smart Scale Carrier Rev A — Project Specification
Purpose
Design a custom Arduino Uno R4 WiFi shield/carrier PCB for the C4 Coffee Co smart coffee scale prototype. Rev A replaces jumper wires and breadboard wiring while preserving the existing working architecture.
Architecture
- Main controller: Arduino Uno R4 WiFi plugged into standard Uno shield headers.
- Load cell: GPB100D digital RS485 load cell, 10 kg / 1 g.
- RS485 interface: existing automatic-flow-control TTL-to-RS485 module.
- Board type: 2-layer Arduino shield/carrier board, 1.6 mm FR4, hand-solderable.
Required Functional Blocks
- Arduino Uno R3/R4 shield headers: D0–D13, power header, A0–A5.
- RS485 module socket: VCC, GND, TXD, RXD.
- Locking 4-pin load-cell connector, preferred JST-XH 2.54 mm.
- Optional industrial load-cell output footprint: M8/panel/screw-terminal equivalent pads.
- 5 V/GND distribution with wide traces and test pads.
- Optional load-cell polyfuse, RS485 TVS protection, termination, bias footprints.
- Future SPI display connector.
- Three buttons plus external button connector.
- Status/error LEDs with current-limiting resistors.
- Arduino-compatible mounting and serviceable edge connector placement.
Pin Mapping
- D0 / RX / Serial1 RX ← RS485 module TXD
- D1 / TX / Serial1 TX → RS485 module RXD
- D2 → TARE button
- D3 → START/STOP button
- D4 → MODE button
- D5 → STATUS LED
- D6 → ERROR LED
- D7 → Display backlight / optional spare
- D8 → Display reset
- D9 → Display DC
- D10 → Display CS
- D11 → Display MOSI
- D13 → Display SCK
Load Cell Connector Pinout
- Pin 1: +5 V / LOADCELL_V+ / RED +V
- Pin 2: GND / BLACK GND
- Pin 3: RS485_A / GREEN A
- Pin 4: RS485_B / WHITE B
Electrical Requirements
- D0/D1 remain dedicated to Serial1 RS485.
- Arduino USB serial remains available for debug/upload.
- No DE/RE control pin is required.
- Load cell +V and RS485 module VCC connect to Arduino 5 V.
- Load cell GND and RS485 module GND connect to Arduino GND.
- RS485 Earth is not connected by default.
- Optional chassis/earth pad remains isolated from logic GND unless bridged by solder jumper.
Prototype / Manufacturing Preferences
- Through-hole connectors where practical.
- 0805 passives preferred.
- 6/6 mil or larger trace/space.
- 0.8–1.0 mm drills where practical.
- Clear silkscreen labels and Pin 1 markers.
- Title silkscreen: “C4 Smart Scale Carrier Rev A”.
Deliverables Target
Flux schematic, PCB layout, manufacturing files, BOM, assembly notes, pinout diagram, and board render.
Purpose
Architecture
Required Functional Blocks
Pin Mapping
Load Cell Connector Pinout
Electrical Requirements
Prototype / Manufacturing Preferences
Deliverables Target
