Just a friendly `save your time/money' heads up to my fellow inventors...
Perhaps you've seen them - the ones advertised like...
" 5V 4-phase 5-wire Stepper Motor Gear Motor 28BYJ-48", sometimes with a ULN2003 driver board.
They claim the gear ratio is 1/64.
It is not.
( It has a gear with teeth=prime number, 31! )
If you just want to make something go round-n-round slowly - go ahead, get one.
If you need to position something accurately - don't.
The actual gear ratio is 1/63.68395062. With 64 steps per motor rev, the number of steps to make the output shaft go exactly one full revolution is 4075.77283968.
Not a nice number, is it?
That said, perhaps my time/effort won't be completely wasted if you help yourself to the Arduino code snippit I wrote for driving it.
It's compact, drives in half-steps and has a psuedo ramp up/down speed thing in it - starts slowly, stops slowly.
I thought it would help keep my positioner from losing steps - and it did - but it didn't solve my problem with, you know, the `I was lied to.' thing.
Look for "Arduino stepper code for ULN2003" in the Microcontrollers and Programming forum.
Good luck with your projects.
Perhaps you've seen them - the ones advertised like...
" 5V 4-phase 5-wire Stepper Motor Gear Motor 28BYJ-48", sometimes with a ULN2003 driver board.
They claim the gear ratio is 1/64.
It is not.
( It has a gear with teeth=prime number, 31! )
If you just want to make something go round-n-round slowly - go ahead, get one.
If you need to position something accurately - don't.
The actual gear ratio is 1/63.68395062. With 64 steps per motor rev, the number of steps to make the output shaft go exactly one full revolution is 4075.77283968.
Not a nice number, is it?
That said, perhaps my time/effort won't be completely wasted if you help yourself to the Arduino code snippit I wrote for driving it.
It's compact, drives in half-steps and has a psuedo ramp up/down speed thing in it - starts slowly, stops slowly.
I thought it would help keep my positioner from losing steps - and it did - but it didn't solve my problem with, you know, the `I was lied to.' thing.
Look for "Arduino stepper code for ULN2003" in the Microcontrollers and Programming forum.
Good luck with your projects.