10. Output Devices


Tenth Assignment:

Contents:

  1. Design my own Aduino Board: FabDuino
  2. Step Motor and driver a4988
  3. Design and build of my own step motor control card
  4. Selft evaluation
  5. File download

Requirement:

  1. Eagle software.
  2. Milling machine.
  3. Electronics components.
  4. Welding station.
  5. A AVR o FabIsp Programmer.

For this assignment I have to add an output device to a microcontroller board I've designed and program it to do something

Design my own Aduino Board: FabDuino

Microcontroller board that I decided to design was a Fabduino Board,


This board use Atmega 328p microcontroller, and is necessary to know more about microcontroller, for that reason I have to read its data sheet, like embedded programming

Microcontroler 328p Data sheet

Some caracteristics are show below



Bloc Diagram


Read More: http://www.atmel.com/images/Atmel-8271-8-bit-AVR-Microcontroller-ATmega48A-48PA-88A-88PA-168A-168PA-328-328P_datasheet_Complete.pdf

On software Eagle are schemamtic and board design, when you design is finish, you need to export as a Image and then using milling machine, Roland Modela Fablab Tecsup case, upload your file.

And the last step or FabDuino fabrication is welding their components




On assignment 4, I explain how to use a milling machine, in tecsup case has a ROLAND MODELA MDX-20

Step Motor and driver a4988

Step Motor

Stepper motors are DC motors that move in discrete steps. They have multiple coils that are organized in groups called "phases". By energizing each phase in sequence, the motor will rotate, one step at a time.


Read More: https://cdn-learn.adafruit.com/downloads/pdf/all-about-stepper-motors.pdf

Driver a4988

The A4988 is a complete microstepping motor driver with built-in translator for easy operation. It is designed to operate bipolar stepper motors in full-, half-, quarter-, eighth-, and sixteenth-step modes, with an output drive capacity of up to 35 V and ±2 A. The A4988 includes a fixed off-time current regulator which has the ability to operate in Slow or Mixed decay modes.



My stepper motor consumed high current, because i didn't set the reference voltaje with the potentiometer on the driver board.


Read More: https://www.pololu.com/file/download/a4988_DMOS_microstepping_driver_with_translator.pdf?file_id=0J450

Programming Microcontroler 328p

In this case also I will need to use Software Arduino IDE to programm my own Fabduino ( because it wors as a normal Arduino)

  1. Go to Tools/Burn Bootloader
  2. Go to File/Example/11.ArduinoISP/ArduinoISP
  3. Develop your program, in my case was a step motor application
  4. Tools/ Programer/ Arduino as ISP
  5. Welding station.
  6. A AVR o FabIsp Programmer.

For this assignment I decided try the Atmel programmer AVRISP MKII



I used the programmer MKII to load the bootloader into my fabduino









After, I loaded the program to controlled the step motor



Finally I test my program on my board




Design and build of my own step motor control card

For this assignment I decide design and build my own motor driver controller, using a attiny44 as microcontroller and a A4953 H-Bridge motor driver, to control a bipolar step motor.
The first step was design my own PCB on my favorite program "Eagle"



The second step is make the PCB, for this I used the Modela milling machine and this use a black and white high resolution PNG image.


This is my board milled and soldered


The next step was load the program to my PCB



Finally I did some tests


Selft evaluation

  1. What worked:
    • I performed the control of my stepper motor with success
    • I Make my own control PCB for my stepper motor

  2. What did not work:
    • I reversed the polarity of the power source of the driver a4988 and I damage it.

  3. Things to improve:
    • Design and implement my own power controller driver

File download