# selecting correct stepper motor to lift 5kg for Arduino project - newbie questions

I am trying to figure out what stepper motor is best for my Arduino project. I want to lift 5kg in steps, doesn't have to be fast, its more important to lift the weight. I have done some calculations and come to the conclusion that I need a 3NM motor (rounding up for additional margin etc).

5kg x 9.8ms2 = 49N 49N x 0.05 = 2.45Nm

5kg x 0.1ms2 = 0.5N

49.5N = upwards force

49.5N x 0.05m = 2.475Nm 49.5N x 0.5m/s = 24.75 Nm/s = 24.75W (0.1m/s would also work bringing down the power requirement)

I've concluded that I can use this motor or this one. Looks like I need a driver too so this motor and driver looks like it would do the job.

Are my conclusions correct? If so is it simply a case of connecting the motor to the driver and the driver to the Arduino using a motor shield such as this one (for multiple motors). Looks like I can't connect the motor to the shield directly because of power requirements. I assume then when its all connected I can use this code to run it. I think I used the stepper motor in that code example before (almost four years ago so I can't quite remember). Also how exactly is the power supplied? To connect two motors I'm thinking it would need 4 PSUs, one for the Arduino, one for the motor shield and one for each of the motor drivers.

Any advice to help me better understand this would be much appreciated.

• You could also use a pulley system to multiply the force of the motor. – Ron Beyer Dec 23 '17 at 0:00
• What is your friction. Also the motor you have chosen is large. – joojaa Dec 23 '17 at 7:22
• @RonBeyer that's certainly an idea. I wouldn't know where to start though. I'd need to work out the correct sizes of the pulley wheels, and if they would take the weight, sames goes for the belt or chain. I had a look for pulley parts and didn't really see anything. – user1532669 Dec 23 '17 at 13:51
• @joojaa Frictional forces are negligible, air resistance perhaps. Its basically a lift so no major frictional forces. – user1532669 Dec 23 '17 at 13:52
• Err. Air resistance but no frictional forces. How fast do really plan to move? – joojaa Dec 23 '17 at 14:46