I'm trying to drive 16 of these little steppers on an Arduino Uno.

Each test driver uses 4 digital pins for control (2 for each coil) so that would be 64 pins I will need.

I'm thinking either getting something like this or 4 of these.

Would something like that work ? What's the most straight forward way to drive these on an Arduino Uno ?

  • I wouldn't get those steppers. One part of the description says it has one chip to drive it, and another part says a completely different chip. Unless you actually have them already, in which case you can manually identify what the chip is on it. The two different chips need completely different driving strategies. – Majenko May 30 '18 at 13:46
  • @Majenko Looks like an ULN2003 (SOIC16 !) driver in the picture, not an A3967 (SOIC24) like in the description. I, personally, would just use 8 shift registers. – Gerben May 30 '18 at 15:57

If you need to drive all 16 simultaneously and independently, the Uno may not have enough capability to do it. Consider the worst-case number of motors and highest rate(s) you expect to drive at once, plus anything else you need the Uno doing at the same time. You might try a simple sketch to do all of these things (substituting LEDs for the motor drivers) at once, and use a scope to examine those LED output signals for the right frequency, wave-form, and lack of jitter. Without I/O expanders, you won't get to 16 motors' worth of outputs (unless you already have an I/O expander) but you might try doubling up on the existing output (use non-overlapping motor phases if you can).

If the Uno can manage that with clean outputs, you'll have a better idea whether it can manage the full load. If it doesn't, you may need to reconsider your choice of processor with respect to its clock-speed, both kinds of memory (depending on what you learned), number of outputs, possibly number of available timers and of interrupts.

  • Alternatively: split the load between multiple MCUs. – Majenko May 30 '18 at 14:29
  • The maximum (reliable) speed I could get with those steppers was at 3ms per step. – Gerben May 30 '18 at 15:49

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