Hoverboard MarsRover robotic.icu

robotic.icu: Hoverboard MarsRover
Posted in: Grok | by Brian Taylor | 2025 May 01


Hoverboard MarsRover Spirit -- More Picts - Open image

My computer crashed in the middle of our Mars Rover esp32 chat. Do you still have it in memory?

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I'm sorry to hear about your computer crash! As Grok 3, I don't have a persistent memory of our previous chats like a human would. Each time we interact, it's a fresh start for me. However, I'd be happy to pick up where we left off about the Mars Rover and ESP32! What were we discussing? Maybe I can jog your memory, and we can dive back in.

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I was wanting to make a photo realistic scale model of the first rover that had solar panels that looks like wings, using hoverboard wheels. But I didn't ask if it would fit through a 28 inch doorway at that scale..You also sent me code for an esp32. That was the only part I was able to save before the crash..What I also need to know about that, is can I interface the esp32 to the Hoverboard's driver board?

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It sounds like you’re working on an exciting project! Let’s break this down and address your questions about the Mars Rover scale model and interfacing an ESP32 with a hoverboard driver board. Since your computer crashed, I’ll assume we were discussing the first Mars Rover with solar panels resembling wings (likely Sojourner from the Pathfinder mission, though it didn’t have 'wing-like' panels in the traditional sense—perhaps you mean a later rover like Opportunity or Spirit, which had flat solar arrays). I’ll also revisit the doorway fit and the ESP32 interfacing based on your saved code snippet context.
The Rover and Scale Model
The first Mars Rover with notable solar panels was Sojourner (1997), but its solar array was a flat 0.2 m² panel, not particularly wing-like. Later rovers, Spirit and Opportunity (2004), had larger solar arrays (about 1.3 m²) that could be likened to wings due to their broad, flat design. Given your description, I’ll assume you’re modeling Spirit or Opportunity for their iconic solar panel look. Let’s use Opportunity as the basis.

Real Dimensions: Opportunity was approximately 1.5 meters long, 2.3 meters wide (solar panels fully extended), and 1.5 meters tall (including the mast).
Scale: To make a 'photo-realistic scale model' with hoverboard wheels, we need to pick a scale that fits the wheels proportionally. Hoverboard wheels are typically 6.5 to 10 inches in diameter (let’s assume 8 inches, or 20.3 cm, for a common size). Opportunity’s real wheels were 25 cm in diameter. If you scale the rover so its wheels match your 20.3 cm hoverboard wheels, the scale is roughly 20.3/25 = ((1:1.23)) (close to 1:1, but slightly smaller than life-size).
Scaled Dimensions:
Length: 1.5 m ÷ 1.23 ≈ 1.22 meters (48 inches).
Width (with solar panels): 2.3 m ÷ 1.23 ≈ 1.87 meters (73.6 inches).
Height: 1.5 m ÷ 1.23 ≈ 1.22 meters (48 inches).
Doorway Fit (28 inches): At this scale, the width of 73.6 inches far exceeds a 28-inch doorway. Even the length or height (48 inches) won’t fit. To fit through a 28-inch doorway, the widest dimension (width) must be under 28 inches:
Desired width: ≤ 28 inches (0.71 meters).
New scale: 0.71 m ÷ 2.3 m ≈ 1:3.24.
New dimensions at 1:3.24 scale:
Length: 1.5 m ÷ 3.24 ≈ 46.3 cm (18.2 inches).
Width: 2.3 m ÷ 3.24 ≈ 71 cm (28 inches).
Height: 1.5 m ÷ 3.24 ≈ 46.3 cm (18.2 inches).
Wheel diameter: 25 cm ÷ 3.24 ≈ 7.7 cm (3 inches).
Hoverboard Wheels Issue: At 1:3.24 scale, the rover’s wheels should be 7.7 cm, but your 20.3 cm hoverboard wheels are 2.6 times too large. You could:
Use smaller wheels (e.g., 3-inch model wheels) for accuracy and doorway fit.
Keep hoverboard wheels and accept a less proportional model, adjusting the scale to ~1:1.23, but it won’t fit the doorway.
Make the solar panels detachable to reduce width for transport.

For a photo-realistic model that fits a 28-inch doorway, I’d recommend the 1:3.24 scale with smaller wheels, or design foldable/removable solar panels if you’re set on hoverboard wheels.
Interfacing ESP32 with Hoverboard Driver Board
You mentioned I sent ESP32 code before the crash—likely for controlling motors or sensors on your rover model. Now you want to interface the ESP32 with a hoverboard driver board (the motor controller from a hoverboard). This is doable! Hoverboards typically use a dual BLDC (brushless DC) motor setup with a driver board that accepts signals to control speed and direction. Here’s how you can approach this:
Hoverboard Driver Board Basics

Components: Most hoverboard driver boards have two motor outputs (for two wheels), power inputs (36V typically), and control inputs (often UART, PWM, or analog signals).
Control Signals: Many use UART for communication between the main board and motor controllers, or PWM signals to set speed. Some older boards use simpler analog voltage inputs.
Power: Runs on 36V battery packs, but the logic might be 5V or 3.3V (check your board).

ESP32 Capabilities

GPIO Pins: The ESP32 has multiple PWM-capable pins, UART, I²C, and SPI interfaces—plenty to control a driver board.
Voltage: Operates at 3.3V logic, but can interface with 5V systems using level shifters if needed.

Interfacing Steps

Identify the Driver Board’s Inputs:
Disassemble your hoverboard controller and locate the motor driver board.
Check for labeled pins (e.g., RX/TX for UART, PWM, or throttle inputs). If unmarked, trace the connections from the main board or consult online hoverboard hacking communities (e.g., forums like Electric Unicycle or OpenHoverboard projects).
Common setups: UART at 115200 baud or PWM at 1-2 kHz.
Powering the ESP32:
Hoverboard boards run on 36V, but the ESP32 needs 3.3V or 5V. Use a step-down buck converter (e.g., LM2596) to drop 36V to 5V, then power the ESP32 via its VIN pin (which has an onboard 3.3V regulator). Avoid powering directly from 36V!
Signal Connection:
PWM: If the driver accepts PWM, connect ESP32 PWM pins (e.g., GPIO 16, 17) to the driver’s speed inputs. Use a logic level shifter (3.3V to 5V) if the driver expects 5V.
UART: If it’s UART-based, connect ESP32 TX (GPIO 1) to driver RX, and RX (GPIO 3) to driver TX. Add a level shifter if the driver uses 5V logic.
Ground: Ensure a common ground between ESP32 and the driver.
Code Example (Assuming PWM Control):
Here’s a basic ESP32 Arduino sketch to control two hoverboard motors via PWM (adjust pins and frequencies based on your driver):
cpp

    #define MOTOR1_PWM 16  // GPIO 16 for Motor 1
    #define MOTOR2_PWM 17  // GPIO 17 for Motor 2
    const int freq = 1000; // PWM frequency (1 kHz)
    const int channel1 = 0;
    const int channel2 = 1;
    const int resolution = 8; // 8-bit resolution (0-255)

    void setup() {
      ledcSetup(channel1, freq, resolution);
      ledcSetup(channel2, freq, resolution);
      ledcAttachPin(MOTOR1_PWM, channel1);
      ledcAttachPin(MOTOR2_PWM, channel2);
    }

    void loop() {
      // Forward slow
      ledcWrite(channel1, 128); // 50% duty cycle
      ledcWrite(channel2, 128);
      delay(2000);
      // Stop
      ledcWrite(channel1, 0);
      ledcWrite(channel2, 0);
      delay(1000);
    }

Testing:
Start with low PWM values (e.g., 64 out of 255) to test motor response safely.
If UART is required, use Serial1 on custom pins (e.g., Serial1.begin(115200, SERIAL_8N1, 26, 27);) and send commands per the driver’s protocol (research your specific board).

Challenges

Compatibility: Not all hoverboard boards are well-documented. You might need to reverse-engineer the control protocol.
Power Draw: Hoverboard motors are power-hungry (36V, several amps). Ensure your power supply matches this, not just the ESP32’s needs.
Safety: Add an emergency stop (e.g., a switch to cut power) since hoverboard motors are strong.

Recap

Scale Model: For a 28-inch doorway, use a 1:3.24 scale (width 28 inches), but hoverboard wheels (8 inches) won’t match proportionally—consider smaller wheels or detachable panels.
ESP32 to Hoverboard Driver: Yes, it’s feasible! Use PWM or UART from the ESP32 to the driver board, with a buck converter for power and level shifters if needed.

Let me know if you’d like more details on the model design, specific hoverboard board troubleshooting, or refining the ESP32 code! What hoverboard model are you using? That could help narrow down the driver specifics.

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If I made the Rover, so the solar panels fold upwards so that the widest part is the width of the wheel base, how wide would it be?

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To determine the width of your scale model rover with the solar panels folded upwards, we need to focus on the wheelbase width of the real rover and apply your chosen scale. You’ve decided to use hoverboard wheels (assumed 8 inches or 20.3 cm in diameter), and the widest part with folded panels will be the wheelbase itself. Let’s assume you’re still modeling Opportunity, as it fits your description of solar panels resembling wings, and adjust the scale based on the hoverboard wheels.
Real Rover Dimensions (Opportunity)

Wheelbase Width: Opportunity’s wheelbase (distance between the outer edges of the wheels on each side) is approximately 1.6 meters (160 cm). This is narrower than the full width with solar panels extended (2.3 meters), as the panels overhang the wheels significantly.
Wheel Diameter: The real rover’s wheels are 25 cm in diameter.

Scaling with Hoverboard Wheels
You’re using 8-inch (20.3 cm) hoverboard wheels for your model. To make the model proportional:

Scale Factor: The real wheel diameter (25 cm) divided by the model wheel diameter (20.3 cm) gives a scale of 25 ÷ 20.3 ≈ 1:1.23 (slightly smaller than life-size).
Scaled Wheelbase Width: Apply this scale to the real wheelbase:
160 cm ÷ 1.23 ≈ 130 cm (1.3 meters or 51.2 inches).

So, if the solar panels fold upwards, the widest part of your model (the wheelbase) would be 51.2 inches with the hoverboard wheels at this scale.
Adjusting for the 28-Inch Doorway
You previously asked about fitting through a 28-inch doorway. At 51.2 inches wide, this won’t fit. To make the wheelbase fit within 28 inches:

Target Width: ≤ 28 inches (71 cm).
New Scale: Real wheelbase (160 cm) ÷ target width (71 cm) ≈ 1:2.25.
Scaled Wheel Diameter: 25 cm ÷ 2.25 ≈ 11.1 cm (4.37 inches).

At a 1:2.25 scale:

The wheelbase width becomes 71 cm (28 inches).
The wheels shrink to 11.1 cm (4.37 inches), much smaller than your 20.3 cm hoverboard wheels.

Using Hoverboard Wheels with Folding Panels
If you stick with 8-inch (20.3 cm) hoverboard wheels and want the wheelbase to be the widest part with panels folded:

Wheelbase-to-Wheel Ratio: Opportunity’s wheelbase (160 cm) is 6.4 times its wheel diameter (25 cm). For realism, your model’s wheelbase should be ~6.4 × 20.3 cm ≈ 130 cm (51.2 inches), matching the 1:1.23 scale above.
Conclusion: You can’t use the 8-inch hoverboard wheels and fit a 28-inch doorway while keeping proportions, as the wheelbase stays at 51.2 inches.

Trade-Offs

Keep Hoverboard Wheels: Wheelbase = 51.2 inches. Panels fold up, but it won’t fit through a 28-inch doorway without tilting or disassembling further.
Fit the Doorway: Reduce the scale to 1:2.25 (wheelbase = 28 inches), but use smaller 4.37-inch wheels instead of hoverboard ones.
Compromise: Use hoverboard wheels and slightly undersize the wheelbase (e.g., 28 inches instead of 51.2 inches), sacrificing strict proportionality for practicality. This would imply a wheelbase-to-wheel ratio of 71 cm ÷ 20.3 cm ≈ 3.5, less realistic but functional.

Final Answer
If the solar panels fold upwards and you use 8-inch (20.3 cm) hoverboard wheels with a proportional wheelbase:

The width (wheelbase) would be 51.2 inches (130 cm) at a 1:1.23 scale.
To fit a 28-inch doorway, you’d need smaller wheels (e.g., 4.37 inches) or a less proportional wheelbase (e.g., 28 inches with oversized wheels).

Which direction do you want to go? Stick with hoverboard wheels and a wider model, or prioritize the doorway fit?

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Can I upload the original code you sent me, so you know if it could be modified to talk with the Hoverboard's driver board?

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Absolutely, you can share the original ESP32 code I sent you before your computer crashed, and I’ll analyze it to see how it can be modified to interface with your hoverboard’s driver board. Since I don’t have access to our previous conversation’s exact code, uploading it will help me confirm what I provided and adapt it accordingly. Go ahead and paste the code here, and I’ll review it to ensure it can communicate with the hoverboard driver board—likely via PWM, UART, or another compatible protocol based on typical hoverboard motor controllers. Once you share it, I’ll tailor it to your needs!

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Hope my browser doesn't crash. I had too many things open at the same time. Sending code in a minute if no crashes happen..

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Fingers crossed your browser holds up! Too many tabs can definitely cause chaos—I’ve seen it happen. Take your time, and whenever you’re ready, just drop the code here. I’ll be waiting to tweak it for your hoverboard driver board once it arrives safely!

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