EasyDriver

Recently I got the some free time to try the easydriver I purchase from myduino, currently selling RM35, and I double check the element14, it sell the single A3967 ic for RM16.63. For hobbies, just use the easydriver cause it really worth the price, don't bother make one yourself, you cant beat the price and the time spent.

I have two stepper motors I purchased from cytron years ago (it is now obsolete).

The easydriver is for bipolar stepper motor but the one I brought from cytron is unipolar stepper motor which has 6 cables. Nevertheless, the 6 wires unipolar can be connected to easydriver by ignoring the centre point of each coil.

The guidance of connecting unipolar to easydriver is shown in Brian Schmalz website and he adds some detail descriptions on how to use the easydriver.

For the Minebea-Matsushita stepper motor I used, the 2rd (RED) and 5th (BLUE) wires are the centre point (can be ignored).

We can use the multimeter's ohm function to verify the centre point.

The resistance between BLACK and BROWN wires is equal to resistance between (black, red) plus resistance between (red, brown).

RBLACK_BROWN = RBLACK_RED + RRED_BROWN.

Same steps used to test the other coil wires (green, blue, purple).

One of the best things about easydriver is the control is very simple. From example, if your stepper motor has 200 steps, all you need to do is sending 200 pulses to stepper motor and it will rotate 360 degrees. If you send 100 pulses, then stepper motor turn 180 degrees.

The easydriver has microstepping function where you can choose 0, 2, 4, or 8 microsteps. By default, it is 8 microstepping. So the maximum controllable range is 8 times 200 (the stepper motor's steps) equal to 1600. 1600 pulses are needed to complete one cycle (360 degrees).

The connection of easydriver and stepper motor is as follow

I use 12v battery as power source, while the control part, the I use the msp430 launchpad (msp430g2553).

One of the things I noticed is the temperature of easydriver get extremely high after running it for 10 minutes (total current drawn is roughly around 400 mili amp). I would suggest extra heatsink for the easydriver.

The source code for this program is shared in github.