Stepper Motor HAT

[k_thod]

Hello,

i was wondering what kind of limitations the Stepper Motor HAT could have when stacked.
If i'm no wrong this is using I2C bus to send commands and should by definition suffer from the bus speed/lack of accuracy when talking of multiple stepper working together.

Also, what about the ability to use the full speed spectrum of those steppers related to the same i2c bus limitation ?

I prefer to be fully aware before buying as i was concidering it after multiple failures with I2C>stepper drivers >stepper motors in term of accuracy.

Thanks

[adafruit_support_bill]

The maximum combined step rate for all motors is limited partly by the i2c bus bandwidth and partly by Python I/O overhead. Step time accuracy is further limited by the Linux operating system.

It is possible to increase the i2c clock frequency (referred to as 'baud rate' in Pi-land). Details vary depending on the model and OS version. Check the Pi forums for details.

Timing accuracy is another story. Since Linux is a time-sharing OS, there is no guarantee that your process will have the CPU at the precise time it needs to take a step. This can lead to uneven motion due to inconsistent step timing.

For high-performance and precise timing with multiple steppers from a Pi, I'd look into the Pololu TIC controllers. These are like mini motion control systems. You can send them commands for speed, acceleration and target position and they will generate the step timing internally. This avoids both the i2c bandwidth problem and the timing uncertainly of Linux.

https://www.pololu.com/category/212/tic ... ontrollers

[k_thod]

Thank you very much, will investigate those TIC controllers.