Close

They Work!

A project log for Unipolar-Feather

Feather to drive a pair of 28byj-48 Unipolar Steppers and Servo for a TurtlePlotBot

RussRuss 01/09/2020 at 06:202 Comments

The new Feather boards arrived just as I was leaving for work today.  I caught myself looking at them several times throughout the day and wondering if they were going to work as well as they looked. It was a long day, but at least I got to write some python code today.

I rushed home, heated up the iron, grabbed the headphones and put on some nice relaxing soldering music.  Nine Inch Nails' 'Pretty Hate Machine' goes well with the smell of rosin core solder. A few songs later and I was ready to test.  And... it... didn't... work. It didn't get hot or smoke but it didn't work. To make a long story short, I had committed an older version of the CircuitPython driver to github and had to figure out where the correct version was stashed.  Once that task was complete, I copied the correct driver to the M4 Feather Express and everything worked. 

I had two of the five Feather boards pre-assembled with the SMT components so the next task will be to pull the chips off the old boards and migrate them to the new bare boards. Should be interesting.  

Discussions

Russ wrote 01/10/2020 at 22:27 point

That was my thought as well after looking at how other boards were getting away with tiny switches. MOSFET's are cheap and big switches are not.

  Are you sure? yes | no

Russ wrote 01/10/2020 at 00:09 point

The switch is a bit chunky but it should handle the max current rating of the driver + a stalled servo.

  Are you sure? yes | no