• Student/prototype robot-car carrier board.
• Arduino Nano ESP32 remains removable via two socket-header rows.
• Two external TB6612FNG driver modules control four brushed DC motors, one H-bridge channel per motor.
• External connectors support two servos, HC-SR04-style ultrasonic distance sensing, front/rear lights, buzzer, battery input, and test points.

• Share a common ground across Arduino, motor drivers, servos, sensor, lights, buzzer, and battery input.
• Drive four motors independently through two TB6612FNG modules.
• Provide protected battery motor power to TB6612 VM pins.
• Provide a separate regulated +5V_SERVO rail capable of at least 3A.
• Protect ESP32 GPIO from 5V sensor ECHO using a 10k/20k divider.
• Switch external lights and buzzer through MOSFET drivers rather than directly from GPIO pins.
• Expose test points for BAT+, 5V_SERVO, 3V3, GND, D8/STBY, D9/RIGHT_PWM, and D10/LEFT_PWM.

• Arduino Nano ESP32 socket interface.
• Dual TB6612FNG module connector placeholders.
• Four separate polarized motor connectors: M_FR, M_RR, M_FL, M_RL.
• Two servo connectors with signal conditioning.
• HC-SR04-compatible distance sensor connector and safe ECHO divider.
• Front and rear low-side MOSFET light drivers.
• Low-side MOSFET buzzer driver with optional flyback diode.
• Battery input path with switch connector, fuse placeholder, and reverse-polarity Schottky placeholder.
• Bulk and local decoupling on motor and servo rails.

Diagram

• Arduino Nano ESP32 represented by two 15-position socket rows.
• User-provided Arduino pin labels are used in documentation and net names: D2, D3, D4, D5, D6, D7, D8, D9, D10, A0, A1, A2, A3, A5.
• The schematic uses one 3V3 pin and one GND pin on the socket placeholder; actual Nano header orientation must be verified before layout.

• Two TB6612FNG external module connectors are schematic placeholders only.
• Each module connector is a 14-pin logical placeholder with documented pin function mapping.
• Exclude from PCB is set on TB6612 module connector placeholders to avoid inventing physical header order or dimensions.
• Each motor has its own H-bridge channel; no motor outputs are paralleled.

• Servo 1 signal comes from Arduino A3 through 100 ohm series resistor and 10k pulldown.
• Servo 2 signal comes from Arduino A2 through 100 ohm series resistor and 10k pulldown.
• Servo power uses +5V_SERVO, not Arduino 3.3V.
• +5V_SERVO regulator is a placeholder requiring final selection after battery and servo specs are known.
• 1000uF bulk and 100nF ceramic are connected on +5V_SERVO near the servo connectors.

• HC-SR04-compatible connector pins are documented as +5V, TRIG, ECHO, GND.
• TRIG is driven by Arduino D6.
• ECHO is divided before Arduino D7 using 10k from sensor ECHO to D7 node and 20k from D7 node to GND.

• Front light control: Arduino A0 -> 100 ohm gate resistor -> Q_FRONT gate; 10k gate pulldown.
• Rear light control: Arduino A1 -> 100 ohm gate resistor -> Q_REAR gate; 10k gate pulldown.
• Light connectors use positive supply plus switched negative.
• LIGHT_SUPPLY_TBD remains uncommitted until light voltage/current are confirmed.

• Arduino D2 drives Q_BUZZER through a 100 ohm gate resistor and 10k pulldown.
• Buzzer connector uses BUZZER_SUPPLY_TBD plus switched negative.
• D_BUZZER is included as an optional flyback/protection diode if the final buzzer is magnetic/inductive.

• J_BAT is polarized and labeled BAT+ / BAT- in documentation.
• Power path: BAT+ -> switch connector -> F1 polyfuse placeholder -> D_RP reverse-polarity Schottky placeholder -> VM_PROTECTED.
• VM_PROTECTED feeds TB6612 VM pins and the placeholder 5V_SERVO regulator input.
• Battery TVS diode is intentionally not finalized or placed because battery voltage is unknown.

Diagram

• Schematic-only draft; PCB layout has not started.
• TB6612 module connectors and 5V regulator are placeholders; final footprints require user-provided dimensions or selected parts.
• Motor, battery, light, and buzzer connector current ratings must be verified after electrical loads are known.
• Mounting holes are M3 placeholders; final hole size and placement require chassis dimensions.

• D2: buzzer drive.
• D3, A5, D9: right-side motor direction/PWM group.
• D4, D5, D10: left-side motor direction/PWM group.
• D8: shared TB6612 STBY.
• D6/D7: ultrasonic TRIG/ECHO.
• A0/A1: front/rear lights.
• A3/A2: servo 1 / servo 2.

• Separate logic, motor power, and servo power areas during layout.
• Keep motor-current paths wide and away from ESP32 signal traces.
• Use star-like power distribution and avoid routing motor current through ESP32 ground paths.
• Add silkscreen labels for every connector and pin after footprints are finalized.
• Stop before layout until approval and missing info are provided.

• No PCB placement or routing was started.
• TB6612 modules are schematic placeholders and excluded from PCB to avoid guessed physical footprints.
• 5V_SERVO regulator is a placeholder; final regulator selection is blocked by missing battery and servo data.
• Battery TVS is intentionally postponed until battery voltage is known.
• Light and buzzer supplies remain configurable through TBD nets.
• User images now identify the intended battery as a Turnigy 3300mAh 4S 14.8V 30C LiPo with XT60, the servo as MG995, the ultrasonic sensor as HC-SR04, the controller as Arduino Nano ESP32 ABX00083, and the motor-driver module as HW-166 TB6612FNG.
• Direct 4S LiPo motor power is incompatible with TB6612FNG VM because the 4S pack is 16.8V fully charged while TB6612FNG VM operating maximum is 13.5V. The next design decision must resolve this before layout.
• The +5V_SERVO rail requirement is updated from 3A minimum to 5A peak recommendation if both MG995 servos may stall at the same time.

• Arduino Nano ESP32 3V3 can supply TB6612 logic VCC only, not servos.
• HC-SR04 sensor power comes from +5V_SERVO unless a separate 5V sensor rail is later requested.
• IRLML6244 MOSFETs are preliminary logic-level low-side switch candidates; final load current must be checked.
• JST PH 2-pin connectors are preliminary polarized connector candidates and may not be current-rated for the final motors/battery.
• The battery connector must be changed to an XT60-class high-current connector or equivalent; the original small 2-pin placeholder is now known to be unsuitable for the 4S LiPo power path.
• F1 and D_RP are functional placeholders only. Final high-current fuse and reverse-polarity protection need a complete motor/servo current budget.

• Initial draft schematic created from the user-provided requirements.
• Project renamed to ESP32 Spy Car Carrier.
• Electrical ERC checks for floating pins, power pins, no-connect, single-pin nets, undriven nets, pin-to-pin issues, and unconnected wire endpoints currently report no ERROR or WARNING results.
• Updated component references from user-uploaded images and recorded the 4S LiPo vs TB6612FNG voltage incompatibility.