stepper motor recommendation

[colorado_hick]

Im getting ready to dig into my 7th or 8th project, but this will be the first one with movement.
My plan is to use a couple of stepper motors to lift a spring loaded beater of some sort and have it thunk the chassis of the project to make a percussive noise. the stepper will rotate 180 degrees, and have to arms that come out that lift the thunker with the first part of their movement then at the end their movement the thunker would clear the arm and come back down on the chassis with a wack. I will adjust the tension of the thunker when I am in prototype mode.

Looking at stepper tutorials in arduino land they are using a controller with a L293D chip. I do not full understand what this is for and I would need one? My hope is that I can run the steppers directly off a 5v board like the 3.5 using a good stepper library, will that work?

Can someone recommend a well-suited bipolar stepper motor that will run on 5v? Im looking for the highest torque I can reasonably get for an application that will never be called on to do more then 250 180degree rotations in a minute.
thanks!!

 

[luni]

Don't use the L293 to drive modern steppers. This ancient chip is only good for very cheap voltage controlled motors like the 28BJ-48. These days practically all steppers are current controlled and need a constant current driver. Depending on the required max current I recommend a DRV8825, A4988, TB6600 or, if you need more professional gear, something like a Leadshine DMXXX.

My hope is that I can run the steppers directly off a 5v board like the 3.5 like the 3.5 using a good stepper library

You always need a driver to generate the high currents required to drive a motor. As for a T3.5 library I recommend TeensyStep: Github Repo. Here the documentation. It is also available using the Arduino lilbrary manager.

Can someone recommend a well-suited bipolar stepper motor that will run on 5v?

There is no such thing. Stepper motors usually need high voltages (12V-60V) to operate.

Im looking for the highest torque I can reasonably get for an application that will never be called on to do more then 250 180degree rotations in a minute.

Something like a NEMA42? https://www.youtube.com/watch?v=yLEz4trSfvo. (Sorry, couldn't resist) But, seriously, you need do do some estimations on the required torque before you can select a suitable motor. The TeensyStep documentation contains some information on how to select a stepper: https://luni64.github.io/TeensyStep/applications2/901_stepper/steppers and on some stepper drivers: https://luni64.github.io/TeensyStep/applications2/902_drivers/drivers