The project is now named AGRO-NAV Rover Controller and contains an 88-component, 66-net complete rover-electronics schematic. It replaces the unsafe LM7805, L298N, and IRF520 approach with protected switching-power rails, external 30 A motor-driver interfaces, fused load branches, IRLZ44N actuator outputs, I²C level shifting, E-stop gating, and transient/flyback protection.
The initial build check reported only an intentional Arduino VIN warning because the Mega is powered through 5V_LOGIC. An independent review also finished, but I could not retrieve and reconcile its final report before execution stopped.
Open items
Confirm each motor’s measured stall current and the actuator stall current.
Recalculate branch fuses, master fuse, wiring gauge, connectors, and driver ratings from those measurements.
The current conservative budget is approximately 40.7 A continuous and 92.8 A non-diversified peak; the 60 A master fuse is provisional.
Review and apply any findings from the completed independent-review thread.
Schematic symbols remain auto-spread rather than manually organized.
Recommended next steps
Reconcile the independent-review report and correct any findings.
Measure or provide the exact motor and actuator models.
Perform a final schematic/ERC review.
Proceed to PCB constraints and layout only after the schematic review is closed.
Execution stopped because your ACUs ran out.
Received notification from "AGRO-NAV Electrical Review" that it finished — picking the work back up.
The independent electrical-review report completed, but I could not retrieve or reconcile its findings, and no additional schematic changes were made in this turn. The project remains at the previously reported 88 components and 66 nets, with motor/actuator current validation, provisional fuse sizing, final ERC review, and any review-driven corrections still open.
The battery input is treated as 10.5–14.4 V and enters through an external master fuse, battery-rated switch, and a 60 A-class ideal-diode/reverse-polarity module.
VBAT_PROTECTED is clamped by SMBJ18A and buffered by 2200 uF / 25 V bulk capacitance.
Each major load has its own fuse so a pump or actuator fault does not remove controller power.
High-current returns are separately named and join at one protected star point. R22–R27 are schematic net ties only; implement them as rated copper links, busbar positions, or a star terminal.
Pump and solenoid use separate low-side MOSFETs, gate resistors, pulldowns, and flyback diodes. The pump also has a local TVS.
Motor and actuator H-bridges remain external because their thermal design, wiring, and current rating exceed a typical student controller PCB.
Provisional Fuse Schedule
Table
Branch
Provisional fuse
Reason
Master
60 A slow-blow
Load-diversified system protection; external holder and cable required
Left drive
20 A time-delay
10 A continuous / 30 A short-peak envelope
Right drive
20 A time-delay
10 A continuous / 30 A short-peak envelope
Pump
10 A
Up to 8 A running, startup to be measured
Actuator
15 A
Provisional 8 A running / 15 A stall
Electronics
7.5 A
Pi, logic, sensor, and servo converter input branch
Solenoid
3–5 A
Up to 2 A coil with inrush margin
Required Real-World Confirmation
Do not purchase final motor drivers, fuses, connectors, cable, or battery hardware until motor stall current is measured. Measure one motor at 10.5 V, 12 V, and 14.4 V-equivalent supply limits if safe, then calculate the two-parallel-motor worst case for each side.
Also confirm:
Actuator running and hard-stall current.
Pump startup and blocked-flow current.
Solenoid coil current and release time with the selected flyback clamp.
External driver logic thresholds and FAULT output type.
Converter continuous ratings at 10.5 V input and elevated enclosure temperature.
SLA manufacturer maximum discharge current and expected capacity at 30–60 A discharge.
Actual USB behavior with VBUS disconnected between the separately powered Pi and Mega; use a USB isolator or approved power-blocking cable if required.
MOSFET Thermal Note
IRLZ44N is specified at logic-level gate drive, including on-resistance test points at 5 V and 4 V. At 8 A, even 25–35 milliohms produces approximately 1.6–2.2 W before hot-resistance increase. Q1 therefore needs a real heatsink or large copper thermal solution, short wiring, and temperature testing. Q2 at 2 A is much less demanding.
Grounding Note
PGND_LEFT, PGND_RIGHT, PGND_PUMP, PGND_ACT, PGND_SERVO, and GND_LOGIC must not be casually daisy-chained. Route each return independently to the protected distribution point. Sensor cable shields, if used, should be terminated deliberately and not carry load current.
Module Selection Guidance
Motor drivers: Cytron MD30C-class or equivalent documented 30 A peak-capable bidirectional modules with PWM/DIR/ENABLE.
Actuator: H-bridge or reversing relay module rated above measured stall current with hardware enable.
Pi converter: regulated 5.1 V at 5 A continuous with input fuse compatibility, low ripple, and thermal derating data.
Logic converter: regulated 5.0 V at 3 A continuous.
Servo converter: regulated 6.0 V, at least 3 A peak and preferably 5 A peak.
Sensor converter: regulated 3.3 V at 0.5 A or more.
Known Justified Review Warning
The Arduino Mega module's VIN power-input pin is intentionally no-connect because the board is powered directly from the protected 5V_LOGIC rail. The ERC power-pin checker may still report this module pin despite the explicit no-connect.