Schematic Draft Report
Worked for 1 min 32 sec
I opened the attachment and began inspecting the current schematic, but I’m blocked because your account has no available ACUs, so AI execution is unavailable right now.
What I accomplished:
- Read the new requirements: add real schematic updates for 4S LiPo power, MOTOR_5V and AUX_5V external buck interfaces, Nano VIN filtering, MOSFET reverse-polarity protection, HW-166 pin order, and removal of power TBD nets.
- Started schematic inspection and confirmed the current design still has old items that need changes, including
J_5V_REG_TBD,D_RP,5V_SERVO,LIGHT_SUPPLY_TBD,BUZZER_SUPPLY_TBD, and current HW-166/Nano placeholder mapping. - Confirmed existing project files are:
What remains:
- Select and add/replace real schematic parts for XT60, 10A fuse, high-current buck interfaces, 30V/15A MOSFET reverse-polarity circuit, and passives/connectors.
- Rewire VM to
MOTOR_5V, servos/sensor/lights/buzzer toAUX_5V, and Nano VIN to protected battery through filtering. - Correct Nano and HW-166 pin mappings.
- Remove
J_5V_REG_TBDand all power-related TBD nets. - Run ERC and update the reports with remaining warnings.
Resume after ACUs
List replacement parts
Locate old placeholders
Check pin mappings
Manual update checklist
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Ask about this doc
Draft Schematic Report
Scope
This report covers the current draft schematic only. PCB placement, routing, and final physical footprints for unknown modules have not been started.
Pin Assignment Table
Table
| Arduino Nano ESP32 label | Schematic net | Destination |
|---|---|---|
| D2 | BUZZER_D2_RAW | R_BUZZER_GATE -> Q_BUZZER gate -> J_BUZZER switched negative |
| D3 | RIGHT_IN2_D3 | J_DRV_R AIN2 and BIN2 placeholder pins |
| D4 | LEFT_IN1_D4 | J_DRV_L AIN1 and BIN1 placeholder pins |
| D5 | LEFT_IN2_D5 | J_DRV_L AIN2 and BIN2 placeholder pins |
| D6 | US_TRIG_D6 | J_USONIC TRIG |
| D7 | US_ECHO_D7_3V3 | HC-SR04 ECHO through 10k/20k divider |
| D8 | MOTOR_STBY_D8 | STBY on both TB6612 module placeholders, TP_STBY |
| D9 | RIGHT_PWM_D9 | PWMA and PWMB on right TB6612 placeholder, TP_RPWM |
| D10 | LEFT_PWM_D10 | PWMA and PWMB on left TB6612 placeholder, TP_LPWM |
| A0 | FRONT_LIGHT_A0_RAW | R_FRONT_GATE -> Q_FRONT gate -> FRONT_LIGHT low-side switch |
| A1 | REAR_LIGHT_A1_RAW | R_REAR_GATE -> Q_REAR gate -> REAR_LIGHT low-side switch |
| A2 | SERVO2_A2_RAW | R_SERVO2_SER -> J_SERVO2 Data, with 10k pulldown |
| A3 | SERVO1_A3_RAW | R_SERVO1_SER -> J_SERVO1 Data, with 10k pulldown |
| A5 | RIGHT_IN1_A5 | J_DRV_R AIN1 and BIN1 placeholder pins |
| 3V3 | 3V3 | TB6612 VCC pins, driver logic decoupling, TP_3V3 |
| GND | GND | Common ground for all subsystems, TP_GND |
TB6612FNG Placeholder Connector Mapping
The same logical pin map is used on J_DRV_R and J_DRV_L. This is not a physical header-order commitment.
Table
| Placeholder pin | Logical TB6612 function | Right-side connection | Left-side connection |
|---|---|---|---|
| Pin_1 | PWMA | RIGHT_PWM_D9 | LEFT_PWM_D10 |
| Pin_2 | AIN1 | RIGHT_IN1_A5 | LEFT_IN1_D4 |
| Pin_3 | AIN2 | RIGHT_IN2_D3 | LEFT_IN2_D5 |
| Pin_4 | AO1 | M_FR_PLUS | M_FL_PLUS |
| Pin_5 | AO2 | M_FR_MINUS | M_FL_MINUS |
| Pin_6 | STBY | MOTOR_STBY_D8 | MOTOR_STBY_D8 |
| Pin_7 | VCC | 3V3 | 3V3 |
| Pin_8 | GND | GND | GND |
| Pin_9 | VM | VM_PROTECTED | VM_PROTECTED |
| Pin_10 | BO1 | M_RR_PLUS | M_RL_PLUS |
| Pin_11 | BO2 | M_RR_MINUS | M_RL_MINUS |
| Pin_12 | BIN1 | RIGHT_IN1_A5 | LEFT_IN1_D4 |
| Pin_13 | BIN2 | RIGHT_IN2_D3 | LEFT_IN2_D5 |
| Pin_14 | PWMB | RIGHT_PWM_D9 | LEFT_PWM_D10 |
External Connector Table
Table
| Connector | Purpose | Pin/function connections |
|---|---|---|
| J_BAT | Battery input | Pin 1 BAT+, Pin 2 BAT-/GND |
| J_PWR_SW | Power switch connector | Pin 1 BAT_RAW, Pin 2 BAT_SW |
| M_FR | Front-right motor | Pin 1 M_FR_PLUS, Pin 2 M_FR_MINUS |
| M_RR | Rear-right motor | Pin 1 M_RR_PLUS, Pin 2 M_RR_MINUS |
| M_FL | Front-left motor | Pin 1 M_FL_PLUS, Pin 2 M_FL_MINUS |
| M_RL | Rear-left motor | Pin 1 M_RL_PLUS, Pin 2 M_RL_MINUS |
| J_SERVO1 | Servo 1 | Gnd -> GND, 5v -> +5V_SERVO, Data -> SERVO1_SIGNAL from A3 through 100 ohm, 10k pulldown |
| J_SERVO2 | Servo 2 | Gnd -> GND, 5v -> +5V_SERVO, Data -> SERVO2_SIGNAL from A2 through 100 ohm, 10k pulldown |
| J_USONIC | HC-SR04-compatible sensor | +5v -> +5V_SERVO, Trig -> D6, Echo -> divider -> D7, Gnd -> GND |
| FRONT_LIGHT | Front light output | Pin 1 LIGHT_SUPPLY_TBD, Pin 2 FRONT_LIGHT_SW_NEG through Q_FRONT |
| REAR_LIGHT | Rear light output | Pin 1 LIGHT_SUPPLY_TBD, Pin 2 REAR_LIGHT_SW_NEG through Q_REAR |
| J_BUZZER | Buzzer output | Pin 1 BUZZER_SUPPLY_TBD, Pin 2 BUZZER_SW_NEG through Q_BUZZER |
| J_5V_REG_TBD | 5V regulator placeholder | Data pin used as VIN from VM_PROTECTED, 5v -> +5V_SERVO, Gnd -> GND |
Note: The servo connector silkscreen must be enforced during layout as GND, +5V_SERVO, SIGNAL. The schematic part pin names are Gnd, 5v, Data.
Power Tree
Diagram
Preliminary BOM
Table
| Qty | Designators | Part / value | Notes |
|---|---|---|---|
| 1 | F1 | RGEF300 polyfuse placeholder | Must be resized after motor stall and servo current are known |
| 12 | R_SERVO1_SER, R_SERVO1_PD, R_SERVO2_SER, R_SERVO2_PD, R_ECHO_TOP, R_ECHO_BOT, R_FRONT_GATE, R_FRONT_PD, R_REAR_GATE, R_REAR_PD, R_BUZZER_GATE, R_BUZZER_PD | Generic resistors: 100 ohm, 10k, 20k | Packages not finalized |
| 6 | C_SERVO_BULK, C_SERVO_DEC, C_VM_BULK, C_VM_DEC, C_DRV_R_VCC, C_DRV_L_VCC | Generic capacitors: 1000uF, 470uF, 100nF | Voltage ratings/packages TBD |
| 3 | Q_FRONT, Q_REAR, Q_BUZZER | IRLML6244TRPBF | Preliminary logic-level N-MOSFET; verify with final load current |
| 3 | J_SERVO1, J_SERVO2, J_5V_REG_TBD | 3-pin 2.54mm headers | J_5V_REG_TBD is placeholder only |
| 9 | J_BAT, J_PWR_SW, M_FR, M_RR, M_FL, M_RL, FRONT_LIGHT, REAR_LIGHT, J_BUZZER | JST S2B-PH-K-S(LF)(SN) | Preliminary polarized 2-pin connector; current rating must be checked |
| 2 | J_NANO_L, J_NANO_R | 15-pin 2.54mm socket strips | Arduino Nano ESP32 removable carrier sockets |
| 2 | J_DRV_R, J_DRV_L | 14-pin 2.54mm header placeholders | Excluded from PCB; physical header order/dimensions required |
| 2 | D_RP, D_BUZZER | Generic Schottky diode | D_RP is reverse-polarity placeholder; D_BUZZER optional flyback if inductive |
| 1 | J_USONIC | HC-SR04 4-pin header | +5V, TRIG, ECHO, GND |
| 7 | TP_BAT, TP_5V_SERVO, TP_3V3, TP_GND, TP_STBY, TP_RPWM, TP_LPWM | Test points | Excluded from BOM by part settings |
| 4 | MH1-MH4 | M3 mounting holes | Excluded from BOM; locations TBD |
ERC / Check Results
Electrical checks run for floating pins, no-connect, pin-to-pin, power pins, single-pin nets, undriven nets, similar labels, and unconnected wire endpoints: no ERROR or WARNING results.
Expected non-schematic/layout-related issues remain because layout has not started:
- Airwires: expected until PCB placement/routing.
- Overlapping copper: expected because components have not been placed on a real board layout.
- Visual label/wire collision warnings appeared during auto-generated net portal wiring; they do not indicate an electrical connectivity error in the current netlist.
User Image Component References Added
Table
| Image reference | Identified component | Schematic reference update | Electrical note |
|---|---|---|---|
| Battery image | Turnigy 3300mAh 4S 14.8V 30C LiPo, XT60 connector | J_BAT marked as XT60-class battery input requirement; current JST PH placeholder is not final | 4S LiPo is 14.8V nominal and 16.8V fully charged; 30C pack can source about 99A, so connector/fuse/wiring must be sized from actual load limits |
| Ultrasonic image | HC-SR04 module, VCC/TRIG/ECHO/GND | J_USONIC marked as HC-SR04 reference | Standard HC-SR04 uses 5V and outputs 5V ECHO; existing 10k/20k divider to ESP32 D7 remains required |
| Servo image | MG995 3-wire servo | J_SERVO1 and J_SERVO2 marked as MG995 references | MG995 variants commonly require 4.8-7.2V and can draw about 1.2-2.5A stall each; +5V_SERVO requirement updated to 5A peak for two servos |
| Arduino image | Arduino Nano ESP32 ABX00083 with u-blox NORA-W106 | J_NANO_L and J_NANO_R marked as ABX00083 references | GPIO remains 3.3V-only; do not connect HC-SR04 ECHO directly |
| Motor driver image | HW-166 TB6612FNG module | J_DRV_R and J_DRV_L marked as HW-166 / TB6612FNG module references | TB6612FNG VM operating maximum is 13.5V, so direct 4S LiPo motor power is incompatible |
| Power connector image | Generic power connector, exact part not readable | J_PWR_SW marked as high-current power-switch/connector placeholder | Need exact part number, voltage rating, current rating, and dimensions |
Newly Identified Incompatibilities
- 4S LiPo vs TB6612FNG VM: TB6612FNG motor supply VM is rated for a 2.5-13.5V operating range. The Turnigy 4S LiPo is 14.8V nominal and 16.8V fully charged, so it must not feed the TB6612 VM pins directly. Fix options are to use a lower-voltage battery, add a motor-power buck regulator sized for motor stall current, or choose motor drivers rated for 4S operation.
- Current rating of existing battery placeholder: The current schematic battery connector started as a small JST PH-style placeholder. That is not suitable for a 30C 3300mAh LiPo power path. Use an XT60-class connector or other verified high-current connector.
- Servo rail sizing: The original minimum +5V_SERVO requirement was 3A. With MG995 servos, two-servo peak current can be about 5A if both stall. The rail requirement has been updated to at least 5A peak unless only one servo will ever be installed.
- Reverse polarity and fuse placeholders: D_RP and F1 are still placeholders. For a high-current 4S battery, the final protection method should be sized from measured/known motor stall current and may need an ideal-diode MOSFET rather than a series Schottky diode.
Component Reference Updates Applied To Schematic Properties
- J_BAT: Turnigy 3300mAh 4S 14.8V 30C LiPo with XT60 requirement; existing connector marked not final.
- J_PWR_SW: high-current power switch/connector requirement added.
- J_NANO_L / J_NANO_R: Arduino Nano ESP32 ABX00083 reference added.
- J_DRV_R / J_DRV_L: HW-166 TB6612FNG module reference and 4S incompatibility warning added.
- J_SERVO1 / J_SERVO2: MG995 servo references added with 2.5A peak-current notes.
- J_USONIC: HC-SR04 reference added.
- J_5V_REG_TBD: input/output/current requirement updated for 4S LiPo to MG995 servo rail.
- C_VM_BULK / C_VM_DEC: VM capacitor voltage requirement updated to at least 25V.
- F1 / D_RP: marked as not-final high-current protection placeholders.
Missing Information Required Before PCB Layout or Final BOM
User-requested required items:
- Battery chemistry and voltage.
- Motor rated voltage and stall current.
- Exact photos and dimensions of both TB6612FNG modules.
- Servo model and voltage.
- Light voltage and current.
- Exact distance sensor model.
Additional required items discovered during schematic drafting:
- Exact Arduino Nano ESP32 socket orientation and whether the carrier should use the standard Nano 15-pin-per-side mechanical outline.
- Final 5V_SERVO regulator choice or whether it should be an onboard buck IC vs external regulator module.
- Connector current ratings for battery, motors, lights, and buzzer.
- Final fuse or polyfuse hold/trip current.
- Final reverse-polarity method: Schottky placeholder vs P-MOS/ideal-diode solution.
- Battery-input TVS standoff voltage after battery voltage is known.
- Chassis mounting-hole size and positions.
- Whether light and buzzer supplies should come from VM_PROTECTED, +5V_SERVO, or a separate rail.
Additional missing data after image review:
- Exact HW-166 TB6612FNG module dimensions, hole spacing, header pitch, header row spacing, and pin order from the actual modules.
- Motor rated voltage and stall current are now critical because the shown 4S battery is too high for direct TB6612 VM use.
- Exact XT60 PCB connector variant/gender and mounting style, or confirmation that the battery connector will be off-board via wires.
- Exact power switch connector/switch part number and current rating.
- Confirmation whether both MG995 servos can operate at the same time; this determines whether +5V_SERVO must be sized for 5A+ peak.
- Final decision: lower-voltage battery, buck-regulated motor rail, or replace TB6612 drivers with 4S-rated motor drivers.
Stop Point
The schematic draft is ready for review. PCB layout must not start until the user approves the schematic and provides the missing physical/electrical information.
Scope
Pin Assignment Table
TB6612FNG Placeholder Connector Mapping
External Connector Table
Power Tree
Preliminary BOM
ERC / Check Results
User Image Component References Added
Newly Identified Incompatibilities
Component Reference Updates Applied To Schematic Properties
Missing Information Required Before PCB Layout or Final BOM
Stop Point
