Powering a stepper motor 5V 28BYJ-48

Other Hardware Motors, Mechanics, Power and CNC
1

I wanted to power the Arduino and 1 stepper motor using batteries without the USB cable supply.

I use 28BYJ-48 5V stepper motor with ULN2003 driver and 9V battery as supply but not enough . Can I use 2pcs 18650 3.7 battery just like this setup but I use Arduino Uno and I will use 18650 battery

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2

A pair of 18650s in series (7.4 volts) and buck converter down to 6V (remember, the ULN is going to drop about 1.2 ~ 1.5V) and power the UNO from 7.4V through the barrel plug or VIN pin. Do not connect 6 volts to the UNO.

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3

A 9volt smoke alarm battery can't provide the current for a motor.
Four AA batteries would be ok though, for a while.

I would use one 18650 first, and see if torque/speed fits your requirement.
Leo..

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4

Thank you

5

So I would put a buck converter before connecting it to the ULN driver ?

6

Yes, motor is 5V, 9 would burn it out. 9V battery -> buck -> ULN -> motor.

7

Yes that is perfect. No boost or buck needed

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10

Well if you use 2 batteries you will have 7.4V.
The ULN driver will drop that to about 6.4V. So you will be applying 6.4V to the motor.

If you use a 5V buck, the ULN will still drop drop the voltage by about 1V. So you will be applying 4V to the motor.

The optimal solution would be to use a 6V buck, then 5V would go to the motor

If you use 6.4V the motor may wear out a little faster.
If you use 4V, it may not work.
6V is just right.

I leave the choice to you

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11

Or you could do this:
The 1N4002 diode will drop the battery voltage about 1V, so the voltage going to the motor wiil be about 5.4V

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14

It'a stepper motor, so it moves in small steps and won't be real smooth.
The RPM will depend on how fast your code runs but I don't think the motor will move any faster than 20RPM when it's powering a little car

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15

About 12 to 15 RPM is all you're going to get without missing steps and stalling, unless you use a library that can provide acceleration / deceleration like AccelStepper or MobaTools.
Drop back to 12 RPM and see if it stops skipping.

16

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