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Topic starter
2022-02-20 12:00 am
Trying to locate a Fritzing type drawing for above using Nano
Similar to this on this link at the end of the page. https://dronebotworkshop.com/stepper-motors-with-arduino/
Using 28BYJ-48 as bipolar 4 wire
Similar to this on this link at the end of the page. https://dronebotworkshop.com/stepper-motors-with-arduino
Seems that the A4988 needs minimum of 9 volt and the motor is 5 volt. How do I allow for that.
What size transformer and amp rating required.
What is the expected current for the 5 volt 28BYJ 5 volt so I can set current limit.
Thankyou
Charles Harris
Topic starter
2022-02-20 12:50 am
While we are at it does the ULN2003 work for bipolar use, with the Nano That is remove the centre tap wire etc and operate
2022-02-21 2:04 pm
Hi @sswcharlie Charles,
I am not sure what you are trying to achieve ... perhaps you have some devious, cunning scheme that I haven't realised, but if stepper motors are new territory for you, I would recommend you start by copying exactly what Bill does in his excellent video as a starting point to become more conversant.
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Bill's forum notes includes the title:
Demo 1 – 28BYJ-48 Unipolar Stepper with ULN2003
which notes the 28BYJ-48 is a Unipolar stepper ... so why are you asking "28BYJ-48 as a bipolar 4 wire"?
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"A4988 needs minimum of 9 volt and the motor is 5 volt. "
Whilst it maybe possible to put higher voltage pulses than the 'continuous' operation voltage that the 28BYJ-48 is designed for, it complicates the matter and increases the chance of 'magic smoke' appearing ... do you need the complexity of this controller when a simple ULN2003 provides 2048 steps (or 4096 half steps) per revolution, allowing for the built-in gearbox?
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"What is the expected current for the 5 volt 28BYJ 5 volt so I can set current limit."
You can either measure your own motor current, with 5V across a coil ... which is how it will be used in most applications. Or accept the resistance in the motor data sheet (assuming it matches your motor exactly), or measure it with a meter, and use Ohm's law to calculate the steady state current when 5V is applied.
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I have no idea what you need a transformer to do. Perhaps you are thinking of a motor power source, in which case it is DC power supply, not just a transformer whose voltage and current capability depend upon the motor chosen.
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"does the ULN2003 work for bipolar use, ..."
As Bill explains, bipolar requires an H-Bridge approach to reverse direction. If perhaps, you were building a clock, that always goes forward, then maybe you could consider the possibility. But if it needs to go in both directions, then the ULN2003 will allow both directions with a Unipolar motor ... but it does not include an H-bridge to reverse the current flow required for a Bipolar arrangement.
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Good luck in your research.
Inst-Tech reacted