PICAXE28A bipolar driver, Please Help!!

L

Logic Rules

New Member
I see there is very little here on the PICAXE28A but I need some informmation direly.
I have what I belive to be two bipolar motors from Epson printers. The printing on them: 2430020 or 6, EM-463, and imbedded in the plastic back, P6. It has four leads, all grey, all going to a 4 pin socket. With my multimeter it tested 8 to 9 ohms on the 1 and 3 pins, and the same on the 2 and 4 pins.

I have the 28-pin Project Board with a L293DNE driver. I am using the amended source from the manual#3, page 17. I am trying to get the PICAXE28A to run this motor but I cannot figure out the configuration to get it going. A diagram with all of the connections would be a great help. There doesn't seem to be enough information in the manual.
I am at a stone wall here. Please Help!!
 
L

Logic Rules

New Member
Thank you for your reply. What little programming knowlege I have spotted the error in the code. What I need is a diagram or photo on where to connect the motor.
Which pins do I connect to? The pins to the right of the ULN2803? In the manual they show the 293 as a separate item with the pin assignments, and not plugged into the project board. I find this very confusing.
 
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L

ljg

New Member
the 4 wires indicates Bipolar. The key to deciding on a driver is our friend Ohms Law, in this case, I=E/R.

I=Amps
E=volts
R= resistance

With 5 volts and 9 ohm coils, that's I=5/9=.556 amps, Just within specs for an L293D. (The "D" means it has internal diodes) The rating is .6 A per coil.

simply adding a 2 ohm resistor in series with the coils, however, would yield around .454 amps per phase, giving a little more margin. pay attention to Heat sinking, however, either though solder traces or a clip-on unit.

A pin compatible 754410 driver would be a little better, a L298 would be even better, though it has a different form factor

Check the printer, if you still have it. Many use an L298 that can be recycled.

The best site for understanding steppers that I've found is Jones on Steppers

a good start for specs on the L293D is HERE
 
L

Logic Rules

New Member
Thanks Larry for the conformation on the motor. I am still in the process of consuming Jones on Steppers, very informative.
Even with the limiting resistors I still need an idea to connect to the project board.
I may have to move the 293 to a protoboard in order to get this thing going but that is such a hassle.
 
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