Good morning everyone. I am still somewhat new to Arduino coding and would appreciate the collective knowledge of the community. I’m currently working on a new project and hit a roadblock. The setup is fairly simple and straightforward but I can’t figure it out to save my life. I need to control two stepper motors (paired) that move in the same direction. Controlled by two momentary buttons or one three position switch, with limit switches on each end. It is a wheeled slider on a straight rail or 2040 aluminum extrusion. I know it’s a rudimentary drawing but I think it makes it clear enough. I appreciate any advice or recommendations that can be offered in this effort. Thank you.
Why two steppers ?
If they’re driving the same sled, one will do.
What’s the mechanical link between the stepper(s) and the sled ?
You don’t really need two limit switches either…
Initialise with a ‘homing’ operation, and then keep track of the position until the next power cycle.
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So this will be mounted vertically and linked by a belt. The only reason I was thinking two motors is because it will be lifting a load of various weights.
I was thinking why two motors too..
Looks like a job for a threaded rod of some sorts..
Some more info will be needed..
Some measurements, max weight..
good luck.. ~q
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The assembly is about 8 feet tall and will be carrying up to 5 pounds.
velocity??
~q
End to end in about 5-10 seconds. Adjustable speed control would be nice.
Will it lift both up and down? Where does the excess belt go? Is the belt actually a loop? How fast will the lift move the weight? Is the second stepper supposed to maintain tension on the belt?
So think of an updated electric version of a dumb waiter. Transporting weighted loads in both directions.
This is a nice article..
understanding required torque for a motor lifting a weight
substituting you weight..
I come up with this..
Check my math, i could be wrong.. 
a stepper motor with a spindle radius of 5 cm for my string that pulls up..
2267.96 5lb in grams
2.26796 kilos
F= ma
= 2.26796 * 9.8 m/s2
F=22.226N force of gravity in newts..
T = Fr
= F * 0.05
=1.1113N torque for gravity
//Torque additional for 1 meter second..
Ta = (2.26796 kg)(1 m/s2) =2.26796 N
//Torque total
Tt = 3N
3N upward force at 0.05m radius T= 3N * 0.05= 0.15Nm
0.15Nm motor size minimum..
power
(3N)(1 m/s) = 3Nm/s = 3W motor power minimum..
Really depends on mechanics..
Think they usually using pulley systems that lighten the load per say..
Velocity is a major factor..
good luck.. ~q
Why stepper at all ?
A motor and gearbox with either a lead screw or looping cable or belt will be faster, cheaper, and easier to control.
As the verticalload increases, consider a counterweight to offset the weight of the carriage, Just like an elevator or dumbwaiter,
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