Help with stepper circuit for novice

Im looking to interface with a inkjet printer with a stepper motor in order to convert it to a flatbed printer for printing baked goods with edible ink. (there are machines on the market that do this as well already)

the goal is keep the existing dc motor and quadrature encoder in place just removing the stock paper feed shaft and letting the motor run as it normally would as a dummy per say.

I would like to tie into the a/b quadrature signal to run the stepper and I understand I will need to use a micro controller and stepper driver to do this, this signal only moves the bed previously the paper not the print head so it will be just 1 axis I need to control.

I would like to run a stepper motor the size of a nema 17, with 2/3 volt rating per coil. the signals from the quadrature encoder a/b are square wave ttl and the high voltage is 3.3 and the low is .08 by my testing with a meter. I also understand I will need a separate power supply and I was intending on running a 24 volt supply with a 5 volt side connection for the micro/ stepper motor power. I also understand I need to know the encoder count to set the pitch electronically so I did order a usb oscilloscope and im waiting on its arrival.

Im looking for the easiest way to achieve this goal. I have did a tremendous amount of reading and it looks as if I can do the signal reading with an interrupt program from a micro (arduino) to follow the encoder and/or possibly there are some micros with onboard a/b quadrature decoders and im not sure how this would affect benefit the objective?

it looks as there are some different choices of drivers I see there is the step and direction based on an atmel chip and a different type based on a big easy driver. I would like to purchase these products along with a microcontroller to get started but I want to make sure im getting the right stuff to accomplish the task. I have spent over a year researching this and I have even paid some micro guys which produced no results due to there limited knowledge. I want to say im an extreme novice with this and have no programming skill but im willing to learn and or use open source sketches to move forward and even pay for results, im down to taking the bull by the horns to figure this out to implement this product into my business rather than outsource. I do understand the printer very well due to making several manual versions using the existing drive components. All help to put me in the right direction would be greatly appreciated regarding a general understanding starting point… like do the quad signals go into the micro and then transferred to the driver…how does it work? after this is accomplished I would like to add a load and eject into the program so push a button the stepper ejects the bed or vice versa.


This sounds like an interesting project; it would be cool to see in action once it is done. Like you mentioned, using a microcontroller to read the encoder signals and control a stepper motor driver is probably the most straightforward way to do it. To start, you might try looking up how quadrature (incremental rotary) encoders work and how they can be used for speed and position control. There is lot of information about them out there. This article on the Arduino site about using encoders might be helpful. Using a microcontroller board with built in support for quadrature encoders, like our Orangutan SVP, might make your program simpler, but those controllers might also have a steeper learning curve and less resources available than the Arduino.