Darlington Array with Bipolar Stepper Motor

I have a bipolar stepper motor (4 pins) and a darlington array. I want to use my arduino to control the stepper using the array. How do I do this?

This is a stepper similar to mine: http://www.nmbtc.com/pdf/motors/PM42S-048-HHC8.pdf
Mine is a nmb-mat pm42s-048-BRY5, but I could not find anything for this.

My Darlington is ULN2803AN

Buy a bipolar stepper motor driver board.

Or buy a motor with 5, 6 or 8 wires.

4-wire bipolar motors cannot be driven unipolar

How about this: ECE 4760

electricviolin:
How about this: ECE 4760

No, thats implicitly passing 12V to the common wire(s), 4-wire motors dont have them

If I get a l293d (I think that is the ic), how would I wire and code that?

Bad choice of chip.
But you wire it up like it says in the data sheet.
You code it like it says in hundreds of examples that google will show you.

Hi,

http://www.nmbtc.com/pdf/motors/PM42S-048-HHC8.pdf

is your motor, the prefix is the manufacturer.

Tom...... :slight_smile:

Grump mike- what ic should I use if this one is a bad choice?

Tom - sorry, I do not understand what you are saying.... Could you please clarify?

electricviolin:
Grump mike- what ic should I use if this one is a bad choice?

It is a bad choice because your motor is only 600mA at 8 ohms. That means only 4.5V to drive it. If you do that you will get poor performance. So you need a driver that incorporates a chopping regulator so that the motor can be driven as fast as it is capable of going.

Use something like this:-

I am using this motor for an extruder for a 3d printer. Will the l293d be powerful enough for that (or i still need more power)? It does not need high speed, only torque.

electricviolin:
I am using this motor for an extruder for a 3d printer. Will the l293d be powerful enough for that (or i still need more power)? It does not need high speed, only torque.

It depends entirley on what motor you are using. If it is like you linked to the answer is still no because you have to arrange the supply voltages to be such that your motor has 4.5V on it when passed through the chip.

The A4988 Mike suggested has several advantages. Besides allowing you to run just about any reasonable voltage, it doesn't throw away the obligatory 1.5-2V of voltage drop you get with any Darlington. The A4988 uses MOSFETs on the output stages. Much more efficient. The "on" resistance is on the order of 7-9 milli-ohms resulting in a much lower voltage drop.

For example, if your stepper draws 2A/phase, with the Darlington you will dissipate 4 W per winding. With the A4988 it will be
2A * 2A * 0.009 or 0.036W per winding. Though it's really 2X that since you have top and bottom devices both dropping but much less heat sink is required, if any at all.

The general theme here is - Darlingtons are very inefficient, they have an obligatory voltage drop; they fail to properly "saturate". This makes them unsuitable for low voltage systems (such as running on 5V supplies) or high currents.

While they may have been in the past, used for high current drivers using large heatsinks, they have been in current practice replaced by FETs with very low "on" resistance.

rmetzner49:
The A4988 Mike suggested has several advantages.

The “on” resistance is on the order of 7-9 milli-ohms resulting in a much lower voltage drop.

Really? Wow, that would be so nice if it were true… Actually its 0.32 ohms typical, 0.43
ohms worst case.

Most integrated stepper driver chips have on-resistances of 0.2 to 0.5 ohms, not 7 milliohms!
If they were 7 milliohms you wouldn’t need to cool them.

Discrete MOSFETs use vertical current flow which means the substrate of the chip
is the drain terminal - you can’t integrate MOSFETs and control circuitry on the
same chip unless all the MOSFET’s drains are commoned at the substrate potential.

Without vertical current flow you can’t get anywhere near 7 milliohm on resistances.

So what IC (NOT controller board such as the A4988) would you recommend? I prefer something from TI because of their service.

The A4988 and A4989: Dual Full-Bridge MOSFET Driver with Microstepping Translator are IC the one they posted is on a breakout board is all.

That would require many external cpmponants. Is there an ic where i have an arduino, power supply, and stepper only?

electricviolin:
That would require many external cpmponants. Is there an ic where i have an arduino, power supply, and stepper only?

It doesn't require much at all two decoupling capacitors is it oh and you have to be able to solder it to a pcb its a 28-contact QFN
theres 3 cap and 3 resistors
For $4.99 I'd by one and use it from ebay no reason not to.

Do you no of any dip (breadboard friendly) ics?

The A4988 from ebay or polo is basically a "dip (breadboard friendly) ics" they just put header pins on it.
It's 1/2 wide and a little over 3/4 inch long whats not there that you really don't want to use one cause these driver chips are going to be smt in any brand you find. so you'll need a breakout board this ones done made.