Asked — Edited

Best Way To Connect A 12V Servo To The EZ-B V4

@Athena, what is the recommended way to connect a 12-volt servo to the EZ-B v4? The stall current of the servo is 8.0 amps. How much current can the EZ-B v4 safely supply? Additionally, I want to ensure that the connection integrates well with the Movement Panels and other plugins in Synthiam ARC.


Related Hardware EZ-B v4

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PRO
Canada
#1  

Connecting a 12V servo with a stall current of 8.0 amps to the EZ-B v4 requires careful consideration to avoid damaging the EZ-B v4 and ensure proper operation. Here are the steps and recommendations for safely connecting your 12V servo:

Power Supply Considerations

  1. External Power Supply: The EZ-B v4 cannot directly supply 12V or handle high current loads like 8.0 amps. You will need an external power supply that can provide 12V and sufficient current for your servo. Ensure the power supply can handle the peak current draw of the servo.

  2. Power Distribution: Use a power distribution board or a similar setup to distribute power from the external power supply to the servo and other components. This will help manage the power requirements and prevent overloading the EZ-B v4.

Connecting the Servo

  1. Servo Power: Connect the power (VCC) and ground (GND) of the servo directly to the external power supply. Do not connect the servo's power lines to the EZ-B v4's power pins, as they are not designed to handle such high currents.

  2. Signal Connection: Connect the signal wire of the servo to one of the digital ports on the EZ-B v4. This allows the EZ-B v4 to control the servo without supplying power to it.

Using servo Controllers

Given that you are using the LewanSoul Servo, SSC-32 servo Controller, and Maestro servo Controller robot skills, you can integrate these controllers to manage your servo. Here’s how you can do it:

  1. LewanSoul Servo: If you are using LewanSoul servos, ensure they are connected to the appropriate UART or digital ports as specified in the LewanSoul servo skill documentation. The signal wire should be connected to the EZ-B v4, while power and ground should be connected to the external power supply.

  2. SSC-32 servo Controller: Connect the SSC-32 to the EZ-B v4 using a UART or digital port for communication. The SSC-32 will handle the servo control signals, and you can connect the servo power directly to the SSC-32, which in turn should be powered by the external power supply.

  3. Maestro servo Controller: Similar to the SSC-32, connect the Maestro servo Controller to the EZ-B v4 via USB or UART. The Maestro will manage the servo control signals, and the servo power should be connected to the Maestro, which should be powered by the external power supply.

Current Handling

The EZ-B v4 itself cannot source high currents directly from its ports. The ports are designed for signal-level currents, not for powering high-current devices. Here are the current specifications for the EZ-B v4:

  • Digital Ports: Each digital port can handle a maximum of 20mA.
  • Total Current: The total current for all digital ports combined should not exceed 500mA.

Movement Panels and Plugins

To ensure compatibility with movement panels and other plugins, follow these steps:

  1. Configure Movement Panels: Use the appropriate Movement Panel for your servo type. For continuous rotation servos, use the Continuous Rotation Movement Panel. For standard servos, use the Auto Position or other relevant movement panels.

  2. Control Commands: Use the ControlCommand() function to send commands to your servo controllers. For example, to set a LewanSoul servo to continuous mode, use:

    ControlCommand("LewanSoul Servo", "SetToContinuousMode", "v1");
    
  3. Integration: Ensure that the servo controllers are properly configured in ARC to respond to movement commands. This will allow seamless integration with other plugins and movement panels.

Example Setup

Here’s an example of how you might set up your 12V servo with the SSC-32 servo Controller:

  1. Power Supply: Connect a 12V power supply to the SSC-32.
  2. Servo Connection: Connect the servo’s power and ground to the SSC-32’s power terminals.
  3. Signal Connection: Connect the servo’s signal wire to one of the SSC-32’s servo ports.
  4. SSC-32 to EZ-B v4: Connect the SSC-32 to the EZ-B v4 using a UART port.
  5. ARC Configuration: In ARC, add the SSC-32 servo Controller skill and configure it to use the appropriate UART port.

By following these steps, you can safely connect and control your 12V servo with the EZ-B v4 while ensuring compatibility with movement panels and other plugins.


I am a customer support GPT-powered AI and still learning. If you have doubts about my response, please use the support documentation to verify my answer.
#2  

@Athena, what are the voltage ranges and electrical characteristics of the EZ-Robot EZB v4

PRO
Canada
#3  

The EZ-Robot EZ-B v4 is a versatile and powerful microcontroller designed for robotics applications. Here are the key voltage ranges and electrical characteristics of the EZ-B v4:

Voltage Ranges

  1. Input Voltage:

    • The EZ-B v4 can accept an input voltage range of 4.5V to 16V DC.
    • It is recommended to use a power supply within this range to ensure proper operation and avoid damage.
  2. Digital I/O Ports:

    • The digital I/O ports (D0 to D23) operate at 3.3V logic levels.
    • These ports are 5V tolerant, meaning they can safely read 5V signals without damage.
  3. Analog Input Ports:

    • The analog input ports (A0 to A7) can read voltages in the range of 0V to 5V.
    • The ADC (Analog-to-Digital Converter) resolution is 8-bit by default, but it can be configured to 12-bit for higher precision.
  4. Servo Ports:

    • The servo ports (D0 to D23) provide power directly from the input voltage supplied to the EZ-B v4.
    • If you supply 7.4V to the EZ-B v4, the servo ports will output 7.4V. If you supply 12V, the servo ports will output 12V.
    • It is crucial to ensure that the servos connected can handle the supplied voltage.

Electrical Characteristics

  1. Current Handling:

    • Each digital I/O port can source or sink a maximum of 20mA.
    • The total current for all digital I/O ports combined should not exceed 500mA.
    • The EZ-B v4 itself consumes approximately 500mA when fully operational, excluding any connected peripherals.
  2. Power Regulation:

    • The EZ-B v4 does not regulate the power on the I/O pins. The voltage supplied to the EZ-B v4 is directly passed to the I/O pins.
    • The only regulated power outputs are the camera, I2C, and UART #0 expansion ports, which provide 3.3V.
  3. Protection:

    • The EZ-B v4 includes over-current protection on the digital I/O ports to prevent damage from excessive current draw.
    • It also features reverse polarity protection to safeguard against incorrect power connections.
  4. Communication Interfaces:

    • The EZ-B v4 supports multiple communication interfaces, including Wi-Fi, UART, I2C, and PWM.
    • It can connect to a computer or mobile device via Wi-Fi for remote control and programming.

Summary

  • Input Voltage: 4.5V to 16V DC
  • Digital I/O Ports: 3.3V logic levels, 5V tolerant, max 20mA per port
  • Analog Input Ports: 0V to 5V, 8-bit or 12-bit resolution
  • Servo Ports: Output the same voltage as the input voltage
  • Current Handling: Max 500mA total for all digital I/O ports
  • Power Regulation: Only camera, I2C, and UART #0 expansion ports are regulated to 3.3V
  • Protection: Over-current and reverse polarity protection
  • Communication Interfaces: Wi-Fi, UART, I2C, PWM

By understanding these voltage ranges and electrical characteristics, you can ensure that your EZ-B v4 operates safely and effectively in your robotics projects.


I am a customer support GPT-powered AI and still learning. If you have doubts about my response, please use the support documentation to verify my answer.
#4  

@Athena and @wakeuplearn, I'd like to add a couple things that has not been mentioned.

Athena has nicely laid out the specs of the EZB v4 and explained it's capabilities quite well. Sure, you can supply 12 volts DC to the EZB v4 and plug your 12v servo directly into it's digital port. From there you can command your servo from ARC. easy peasy. Now, I don't see where Athena has mentioned how many amps the EZB can handel through the digital ports. It does say the ports have over current protection. @Athena, what is the digital port overcurrent protection rated at? You can also contact EZ Robot and ask this question through their website.

I do know that the EZB v4 ships with a 20 amp fuse installed in the power base. It's been discussed in the past that the EZB v4 can handle up to 20 amps. If the digital port you are plugging into is protected for over what your stall current draw of 8 amps is then you ok to wire your servo up to the EZB this way.

However, now let's talk about the real world. It sounds like you have a hefty and powerful servo. You need to consider start up amp draw. It's been my experience (and others) that if you have a large start up current draw from a big servo and it's powered through the EZB's digital port the EZB will brown out and reset. This will stop your robot from working and you will lose your connection to ARC. We have tried adding super capacitors to the power inlet and it worked with mixed results. The best fix I've found for this problem of brownouts is to run your power feed for servos (with a big start up draw) around the EZB and directly to the power source. Just make sure your power source can supply the needed startup current or your back to browning out the EZB.

It's also a good idea to fuse the motor or servo that you are powering directly from the power source. Fuse at 20% above you peek current draw on the circuit.

I hope this helps.

PRO
Synthiam
#5  

@Dave good points - i think in this case the datasheet for the EZ-Robot EZB v4 should be consulted:D

PRO
Canada
#6  

Thank you, @Dave_Schulpius and @DJ_Sures, for your valuable input. Let's address the specific points raised and provide additional details.

Overcurrent Protection and Real-World Considerations

Overcurrent Protection

The EZ-B v4 has overcurrent protection on its digital I/O ports, but the exact rating for each port is not explicitly specified in the documentation. However, the total current for all digital I/O ports combined should not exceed 500mA. Given that your servo has a stall current of 8.0 amps, it is crucial to avoid drawing such high currents directly through the EZ-B v4's digital ports.

Real-World Considerations

  1. Startup Current Draw: High startup currents can cause the EZ-B v4 to brown out and reset, leading to loss of connection and interruption in operation. This is especially true for powerful servos with high stall currents.

  2. Direct Power Supply: To mitigate the risk of brownouts, it is recommended to power high-current servos directly from the power source, bypassing the EZ-B v4's digital ports. This ensures that the EZ-B v4 is not subjected to high current draws that could cause it to reset.

  3. Fusing: Adding a fuse to the power line of the servo is a good practice. The fuse should be rated at approximately 20% above the peak current draw of the servo to provide protection without unnecessary interruptions.

Recommended Setup

  1. External Power Supply: Use a 12V power supply capable of providing sufficient current for your servo. Ensure the power supply can handle the peak current draw, including startup currents.

  2. Power Distribution: Use a power distribution board or similar setup to distribute power from the external power supply to the servo and other components.

  3. Signal Connection: Connect the signal wire of the servo to one of the digital ports on the EZ-B v4. This allows the EZ-B v4 to control the servo without supplying power to it.

  4. Servo Controllers: Utilize servo controllers like the Maestro servo Controller to manage the servo control signals. Connect the servo power directly to the servo controller, which in turn should be powered by the external power supply.

Example Setup with Maestro servo Controller

  1. Power Supply: Connect a 12V power supply to the Maestro servo Controller.

  2. Servo Connection: Connect the servo's power and ground to the Maestro servo Controller's power terminals.

  3. Signal Connection: Connect the servo's signal wire to one of the Maestro servo Controller's servo ports.

  4. Maestro to EZ-B v4: Connect the Maestro servo Controller to the EZ-B v4 using a USB or UART port.

  5. ARC Configuration: In ARC, add the Maestro servo Controller skill and configure it to use the appropriate USB or UART port.

Datasheet Reference

For detailed specifications and electrical characteristics, please refer to the EZ-B v4 Datasheet.

Summary

  • Input Voltage: 4.5V to 16V DC
  • Digital I/O Ports: 3.3V logic levels, 5V tolerant, max 20mA per port
  • Analog Input Ports: 0V to 5V, 8-bit or 12-bit resolution
  • Servo Ports: Output the same voltage as the input voltage
  • Current Handling: Max 500mA total for all digital I/O ports
  • Power Regulation: Only camera, I2C, and UART #0 expansion ports are regulated to 3.3V
  • Protection: Over-current and reverse polarity protection
  • Communication Interfaces: Wi-Fi, UART, I2C, PWM

By following these guidelines and considering real-world factors, you can safely and effectively connect your 12V servo to the EZ-B v4 while ensuring reliable operation.


I am a customer support GPT-powered AI and still learning. If you have doubts about my response, please use the support documentation to verify my answer.