How to know that your Arduino can handle a servo motor?

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Discussion Overview

The discussion centers around whether an Arduino can handle the power requirements of a servo motor, specifically the "Carson-model Sport 500502015 CS3 Reflex racing servo" and smaller 9G microservos. Participants explore the current draw of these servos, the appropriate power supply configurations, and best practices for connecting servos to an Arduino for a robotic arm application.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions how to determine if the Arduino can handle the servo motor, expressing concern about current draw and potential damage.
  • Another participant requests the specific Arduino model to provide more tailored advice.
  • It is noted that the Arduino UNO R3 is being used in this context.
  • One participant suggests linking to the servo's specification sheet to check its current requirements and recommends using a separate power supply for the servo while controlling it with the Arduino.
  • A participant asserts that most servos can draw significant current, which exceeds the Arduino's capacity, and emphasizes that the Arduino should only send the PWM signal while the servo is powered separately.
  • Another participant clarifies that while Arduinos can supply a few hundred mA, this is not typical for microcontrollers and warns against assuming this capability is standard.

Areas of Agreement / Disagreement

Participants generally agree that the Arduino should not power the servo directly and that a separate power supply is advisable. However, there is uncertainty regarding the exact current limits of the Arduino and the specific power requirements of the servo motors, leaving some aspects of the discussion unresolved.

Contextual Notes

Participants mention varying current draw specifications for servos and the Arduino's power output capabilities, indicating a need for precise specifications to make informed decisions. There is also a lack of consensus on the exact current limits of the Arduino.

trickybilly
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I am very new to electronics. How to know if my Arduino can handle a motor? I have a "Carson-model Sport 500502015 CS3 Reflex racing servo" - is it ok and how to know? Afrotechmods said that plugging a bigger motor (anything that draws more than a few mA) would be bad for an Arduino. How can I know if it will be too much for an Arduino? I have 2 of these mentioned motors and 2 "little blue" 9G microservos. If I join all 4 for a robotic arm will that be too much?
 
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Can you tell us what Arduino you have?
 
Arduino UNO R3
 
I believe you are talking about servos used in RC models. If so - it can't, most servos can draw quite a current (often measured in amperes) while the Arduino survives up to tens mA loads (I am not sure now whether it is 50 mA total or 200 mA total, but we are definitely speaking an order of magnitude difference).

However, when driving such a servo you don't power it from the Arduino. Arduino is there just to send the controlling PWM signal, and it can be done directly.

Servo has three wires - black goes to a common ground, red goes to the power (5 V from the BEC or UBEC or something like that), third goes to the PWM source, be it the receiver or the Arduino or whatever. All three wires are part of one cable together and typical receiver supplies the necessary power, so there is only one plug, but it doesn't have to be this way.
 
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I also want to make a note...
An arduino is really just a special microcontroller. Normal micrcontroller you can NEVER pull current more than a few mAs out of. With arduino, there is a 5V rail that is supplied that is also used to power the microcontroller on the board. This means you can pull a few hundred mA from it (which is probably not enough for your application).

If it is enough for your application, don't fall into the trap of thinking it is the norm. You can only do this because arduinos are designed for easy prototyping.
 

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