This four-wheel robot uses an STM32F103C8T6 Blue Pill as its controller, an HC-05 Bluetooth module for smartphone commands, and an L298N H-bridge to drive four geared motors. Its reference build also includes a small I2C OLED and two Li-ion cells. It is an educational project architecture—not a complete, validated wiring plan: the source does not specify pin assignments, battery configuration, motor current, firmware, or measured range and runtime.
How the robot is organized
The Blue Pill handles incoming Bluetooth commands, movement logic, and OLED updates. The HC-05 provides the wireless serial link to a smartphone. Between the microcontroller and the motors sits the L298N motor driver: the STM32’s GPIO pins provide control signals, while the driver switches motor power. The OLED provides a local display interface.
Electronics For You describes movement forward and backward, turning left and right, and rotating through 360 degrees. Those are the project’s stated capabilities; the article does not establish independently measured performance or a particular control algorithm.
Reference parts list
The following is the bill of materials described by Electronics For You, not a recommendation for a specific product listing or a verified compatibility guarantee.
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| Part | Quantity and stated specification | Role |
|---|---|---|
| STM32F103C8T6 Blue Pill board | 1 | Runs the control logic and communicates with peripherals. |
| HC-05 Bluetooth module | 1 | Provides the Bluetooth serial connection. |
| L298N motor driver | 1 | Switches motor power in response to controller signals. |
| BO geared motors | 4 dual-shaft motors, listed at 200 rpm | Drive the four-wheel chassis. |
| 0.96-inch I2C OLED | 1 | Displays information from the controller. |
| Li-ion cells | 2 cells, each listed as 3.7 V and 2000–2500 mAh | Battery supply; the cell configuration is not stated. |
| Two-cell holder | 1 | Holds the cells. |
| SPST switch | 1 | Provides a power switching point. |
| 3D-printed chassis | 1 compact four-wheel chassis | Supports the motors and electronics. |
What to verify before wiring
The component list identifies a project concept, but does not settle the electrical details needed for a safe, reproducible build. Check the exact board, module, motors, driver breakout, and battery parts you have; products sold under the same family name can differ.
- Confirm the controller. Check the chip marking and the board’s regulator and pinout. ST’s STM32F103C8 product information specifies a 72 MHz Cortex-M3, three USARTs, and a 2.0–3.6 V MCU supply range. Those MCU specifications do not guarantee that every third-party Blue Pill board has the same assembly or regulator behavior.
- Check UART voltage compatibility. Do not infer the HC-05 breakout’s VCC or RX-pin limits from its name. Consult the documentation for the exact module and board, and ensure the MCU’s 3.3 V logic and the module’s inputs are compatible. ST’s STM32F103x8/xB datasheet is the reference for the MCU’s electrical characteristics, not for the HC-05 breakout.
- Match motor current to the driver and supply. Find the motors’ rated and stall current, then compare them with the specific L298N module’s limits and thermal behavior. The project’s parts list does not provide motor-current measurements or validate a particular driver module.
- Resolve the battery and power path. Two cells rated 3.7 V each do not, by themselves, establish whether the build connects them in series or parallel, what voltages reach each board, or how the system is regulated. Confirm cell arrangement, suitable charging and protection, switch rating, and regulator requirements for the selected parts.
- Plan a shared electrical reference. The controller, Bluetooth module, and driver control inputs need a compatible signal reference; verify the intended common-ground arrangement in a circuit diagram for the exact hardware. The BOM is not a wiring diagram.
What the project description does not specify
The Electronics For You description and BOM do not establish exact GPIO assignments, a schematic, firmware setup, smartphone app compatibility, Bluetooth range, battery runtime, or tested motor performance. Those details should come from a matching schematic and firmware reference or be worked out for the exact parts used; they cannot be inferred from the component names or battery capacity alone.
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Choosing compatible parts
If assembling the reference design, use the named parts as a starting point rather than treating the list as a guarantee that any listings will work together. Check that the board exposes the needed peripherals, the Bluetooth module’s UART and power requirements match the controller interface, the motor voltage and stall current suit the driver, and the chassis fits the chosen motors. Confirm that the OLED uses the expected I2C interface and that the battery arrangement and regulation supply every component within its limits. The source does not compare alternatives or provide verified speed, efficiency, range, or value rankings.
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