3x4 keypad for stepper motor control..need help

[melai]

please help.. i am using pic16f84a for my project. the problem goes like this..

once i press a number from my keypad(its from -360 to 360 degrees) and when i press enter button(not included in pic) then the stepper motor will move as indicated in the lcd. the stepper motor has a driver and its requirements are clock pulses and direction(its either positive or negative supply)..

please help...thank u..

 

[hjl4]

So what are you trying to do.
I'm guessing you want the stepper motor to move equivalent number of degrees you have punched in on the keypad, have lcd display that, and then on 2nd line of lcd, the actual position of the motor? So basicaly, show set points, and then actual position??

Your not explaining yourself to well.

 

[cadstarsucks]

please help.. i am using pic16f84a for my project. the problem goes like this..

once i press a number from my keypad(its from -360 to 360 degrees) and when i press enter button(not included in pic) then the stepper motor will move as indicated in the lcd. the stepper motor has a driver and its requirements are clock pulses and direction(its either positive or negative supply)..

please help...thank u..

It looks like you are want to know how to access a keypad. While that depends a lot on the keypad you are using, they are usually set up in rows and columns with the switch connecting the two.

You need to drive a column high and read the result on the row for each column and debounce it in software. Depending on the type of port pin you use to drive the columns you might need to add blocking diodes as well.

I do not know how much your driver IC is but you could drive the motor directly through FETs as well.

D.

 

[melai]

thank you very much...im working also on keypad and appying scanning technique..i used stepper driver circuit that needs only a clock pulses and direction(positive or negative).
thank you..

 

[hjl4]

So help us understand you. Are you getting this cadstarsucks?? What micro is he using?? What type of motor, Unipolar Bipolar???Did I miss something?

 

[melai]

i'm using unipolar stepper motor.it has 147 clock pulses in order to rotate 360 degrees.im using pic16f84a.the driver is good.i've tested it. the only thing i use to drive the circuit is a clock timer(LM 555 ckt). and a supply. so maybe its the thing that i must provide to output on the pic16f84a..

 

[hjl4]

So your steppers are 2.44 degrees per pulse. x 147 = 358.68deg

I think you would have to do microstepping.

Read the file you used to display results on lcd, and decrement or increment a temporary file to desired number, then read that file, and display the new results on lcd.

Make sense?

Other people are much better then me at motor control.

 

[hjl4]

If I'm not mistaken, Microchip has an application note(ANxxx) about how to accomplish what you want to do.
If not, Nigel's tutorials page, also does keypad scanning.

 

[hjl4]

Here is link.

 

[melai]

thank you very much...ok, i'll work with that..