Question arduino and servo motor

PaulosK

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May 25, 2019
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I want to make something using 2 servo motors, an arduino and one more component. Can I power the servo motors and the arduino from the same powerbank if the powerbank has 3 outputs? If I can't power all 3 of them or if I can't find a powerbank with 3 outputs, can I use a powerbank for the arduino and a seperate powerbank with 2 outputs for the 2 servos?
 

OldSurferDude

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May 18, 2019
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When you write "power bank" does one assume you mean a 5V supply that would normally supply power for a cell phone?

There are a lot of anemic "power banks". The ones about the size of a fat cigar can provide 5V @ 500mA for an hour and a half, barely enough for one motor.

rant on power banks. The specs are usually for the batteries inside them, not @5V. even then, I have never found a power bank to live up to expectations. The best ones provide about 80% of spec mAhr and the useable output current about the same.

My experience with motors is that, because motors are electrically noisy, each should have its own power supply. Putting an appropriate electrolytic capacitor across the motor probably could allow for one supply. But ...

How much power will the motors need? Let's say 1/2 oA per motor. For you other component 100mA and 50mA for the Arduino. So three fat cigars will get you about an hour and a half.

So check the specs of your motors, other component, and Arduino. Size the power bank (using real numbers) for twice what they will use.

I hope the project works out for you.
 
Reactions: PaulosK

PaulosK

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May 25, 2019
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When you write "power bank" does one assume you mean a 5V supply that would normally supply power for a cell phone?

There are a lot of anemic "power banks". The ones about the size of a fat cigar can provide 5V @ 500mA for an hour and a half, barely enough for one motor.

rant on power banks. The specs are usually for the batteries inside them, not @5V. even then, I have never found a power bank to live up to expectations. The best ones provide about 80% of spec mAhr and the useable output current about the same.

My experience with motors is that, because motors are electrically noisy, each should have its own power supply. Putting an appropriate electrolytic capacitor across the motor probably could allow for one supply. But ...

How much power will the motors need? Let's say 1/2 oA per motor. For you other component 100mA and 50mA for the Arduino. So three fat cigars will get you about an hour and a half.

So check the specs of your motors, other component, and Arduino. Size the power bank (using real numbers) for twice what they will use.

I hope the project works out for you.
here are the specs of the servo i am thinking of buying:
  • Operating Voltage Range: 6V - 7.4V
  • Idle current (at stopped): 6mA@7.4V
  • No load speed: 0.192sec/60°@7.4V
  • Runnig current(at no load): 180mA@7.4V
  • Peak stall torque: 35.5kg.cm@7.4V
  • Rated torque: 11.8kg.cm@7.4V
  • Stall current: 3.9A@7.4V
i have no idea what any of these mean, I am still learning. Here is the link for the motor: https://grobotronics.com/servo-standard-35kg.cm-metal-gears-feetech-ft5330m.html
Most powerbanks (yes, i meant a power supply that is used to charge a phone) say the can provide from 5v-9/12v by changing the current, or that's what i have underastand at least. I want the project to be portable and chargeable, so you don't have to change batteries every time you run out of power. I was thinking of using usb converter modules.
 

OldSurferDude

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May 18, 2019
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These will require a bit of power. I would suggest you design to the rated values 1.3A (3.9 * 11.8 / 35.5) @ 6V I don't know how to trick a power bank to providing 6V. The best (most expensive) power banks can provide 3A. I would suggest a 6V lead-acid battery (plus charger) for the voltage and cost. A 4Ahr-6V battery would give you 4/(2*1.3) hours of operation (if the battery can actually provide 4Ahr @ greater than 6V).

While I have every reason to believe that you can control this servo directly with an Arduino, you may need need a level shifter.

To protect the motors and at the same time the battery, through a voltage divider, you could have the Arduino monitor the 6V battery voltage level and shut down when the voltage goes below 6V. The lead-acid battery needs to be protected from deep cycling, which is death to the battery. Have three or more LEDs to indicate battery voltage level. (Just a note: the first laptop computer's battery control circuitry had more computing power than the computer.)

Hope this helps
 
During the development of your "thing", you can run these motors directly off Arduino, powering it with your power bank. Then, depending on the load on the motors, you might have to use servo drivers and extrnal power source.
 
Apr 20, 2021
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Hi,
Arduino is a microcontroller that used C++ programming to operate many sensors and motors.
The Servo motor can be run by Arduino with some simple steps. Arduino has only two types of input parts
  1. By USB
  2. By using the connector
If you want to connect Arduino you need two output devices to operate one is for microprocessor and the second is for servo motors or sensors.
When I was making a robotic car with the help of Arduino I used a laptop USB port to supply Arduino and used a battery for the four servo motors supply.
I think you understand all the connections that I have made.

Thanks:)
 

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