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Tech-dat/acturator-dat/motor-dat/servo-dat/servo-dat.md
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@@ -76,6 +76,58 @@ The fixed-wing S-version servo (with 25cm wire length) is not the helicopter ver
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![](2025-04-09-15-37-30.png)
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+### servo with five wires
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+
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+![](2026-02-28-01-37-32.png)
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+
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+A 5-wire servo consists of a **DC Motor** and a **Potentiometer** (feedback sensor) without an internal control board. To use it, you must provide an external motor driver and a microcontroller.
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+
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+---
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+
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+#### 1. Wiring Diagram
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+
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+##### The Potentiometer (Feedback)
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+The three wires connected to the potentiometer act as a **Voltage Divider**.
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+
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+* **Wire 1 (Outer):** Connect to **VCC** (3.3V or 5V from MCU).
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+* **Wire 2 (Center/Wiper):** Connect to an **Analog Input Pin (ADC)** on your Microcontroller.
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+* **Wire 3 (Outer):** Connect to **GND**.
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+
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+##### The DC Motor (Power)
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+* **Wire 4:** Connect to **Motor Driver Output A** (e.g., OUT1 on DRV8701).
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+* **Wire 5:** Connect to **Motor Driver Output B** (e.g., OUT2 on DRV8701).
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+
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+
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+
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+#### 2. Technical Specifications & Calculations
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+
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+##### Potentiometer Feedback
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+The voltage read by the ADC tells you the current position.
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+$$V_{out} = V_{cc} \times \frac{R_{lower}}{R_{total}}$$
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+As the motor turns the gears, the resistance changes, and the voltage shifts linearly with the angle.
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+
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+##### Control Logic (The Feedback Loop)
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+Since there is no internal IC, your code must perform **Closed-Loop Control**:
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+
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+1. **Read Position:** Get the current analog value ($Current\_Pos$).
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+2. **Calculate Error:** $Error = Target\_Pos - Current\_Pos$.
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+3. **Drive Motor:** * If **Error > Threshold**: Drive Motor CW (Clockwise).
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+ * If **Error < -Threshold**: Drive Motor CCW (Counter-Clockwise).
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+ * If **Error ≈ 0**: Stop Motor (Brake).
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+
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+
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+
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+#### 3. Why Use This Setup?
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+
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+| Feature | Standard 3-Wire Servo | Raw 5-Wire Servo |
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+| :--- | :--- | :--- |
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+| **Control Board** | Internal (Built-in) | External (MCU + Driver) |
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+| **Customization** | Limited by internal IC | Fully programmable PID |
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+| **Current/Torque** | Limited by tiny internal MOSFETs | Limited only by your external driver |
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+| **Response** | Fixed 50Hz PWM | High-speed real-time control |
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+
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+
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+
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## Knowledge
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The control of the steering gear generally requires a time base pulse of about 20ms. The high level part of the pulse is generally the angle control pulse part in the range of 0.5ms-2.5ms, and the total interval is 2ms.
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@@ -215,6 +267,38 @@ connector to a [[crank-dat]]
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![](2026-02-28-01-19-43.png)
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+### servo shaft
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+
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+#### 1. Standard Servo Shaft (25T Spline)
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+
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+The most common standard for hobbyist and robotics servos is the **25T (25-tooth)** spline, often referred to as the "Futaba" or "PowerHD" standard.
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+
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+* **Outer Diameter (OD):** **5.90 mm to 6.00 mm** (measured at the peaks of the teeth).
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+* **Inner Diameter (ID):** Approximately **5.40 mm** (measured at the valleys of the teeth).
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+* **Spline Count:** **25 Teeth**.
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+* **Center Screw:** Typically requires an **M3** machine screw.
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+
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+
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+
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+#### 2. Micro Servo Shaft (e.g., SG90, MG90S)
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+
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+If you are using smaller servos for the **Rover V2** (for sensors or light mechanisms), the dimensions are smaller:
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+
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+* **Outer Diameter (OD):** **4.80 mm to 4.90 mm**.
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+* **Spline Count:** Usually **21 Teeth** (21T) or sometimes **20T**.
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+* **Center Screw:** Typically requires an **M2** or **M2.5** screw.
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+
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+
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+
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+#### 3. Comparison Table for Design
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+
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+| Servo Class | Typical Model | Shaft OD (mm) | Spline Count | Screw Size |
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+| :--- | :--- | :--- | :--- | :--- |
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+| **Micro** | SG90 / MG90S | ~4.85 mm | 21T | M2 / M2.5 |
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+| **Standard** | MG996R / S3003 | ~5.95 mm | 25T | M3 |
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+| **Large/Giant** | HS-805BB | ~8.00 mm | 15T / 17T | M4 |
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+
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+
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## code
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- [[code-dat]]
Tech-dat/acturator-dat/motor-dat/servo-dat/servo-rank-dat/2026-02-28-01-24-21.png
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Tech-dat/acturator-dat/motor-dat/servo-dat/servo-rank-dat/servo-rank-dat.md
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@@ -13,21 +13,28 @@
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| MG996R | 9~15 | | | [[SCU1012-DAT]] |
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| MG995 / MG946R / MG945 | 9~13 | | | [[SCU1012-DAT]] |
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| PTK 7465 7465W | 5.8 @ 8.4V | | | |
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-| SG92R | 2.5 | | | |
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-| ES08MA | 1.8 @ 6V | | 55g | |
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+| SG92R | 2.5 | | 9g | |
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+| EMAX ES08MA | 1.8 @ 6V | | 9g | |
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| SG90 | 1.6 | | | [[SCU1030-DAT]] |
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| MG90S / MG90 | 2.0 | | | [[SCU1031-dat]] |
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+| PTK 7350MG-D 5.5g |
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+
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+
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- [[current-dat]]
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## nangu
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-steel gears
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+steel gears, gears number == x4 or x5
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![](2026-02-28-01-13-38.png)
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+![](2026-02-28-01-24-21.png)
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+
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## ref
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-- [[servo-dat]]
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\ No newline at end of file
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+- [[servo-dat]] - [[servo]]
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+
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+- [[robot]]
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\ No newline at end of file