S18: XY-Plotter - Revision history

Proj user12: /* Project Video */

2018-05-27T07:58:45Z

‎Project Video

Proj user12: /* Servo motor */

2018-05-27T07:23:04Z

‎Servo motor

Proj user12: /* NEMA 17 Stepper Motor */

2018-05-27T07:20:35Z

‎NEMA 17 Stepper Motor

Proj user12: /* System Overview and Mechanism */

2018-05-27T07:17:57Z

‎System Overview and Mechanism

Proj user12: /* System Overview and Mechanism */

2018-05-27T07:17:49Z

‎System Overview and Mechanism

Proj user12: /* Conclusion */

2018-05-27T07:15:47Z

‎Conclusion

Proj user12: /* Printed Circuit Board (PCB) */

2018-05-27T04:25:59Z

‎Printed Circuit Board (PCB)

Proj user12: /* Printed Circuit Board (PCB) */

2018-05-27T04:22:34Z

‎Printed Circuit Board (PCB)

Proj user12: /* Erroneous movement of stepper motor using PWM */

2018-05-27T04:05:50Z

‎Erroneous movement of stepper motor using PWM

Proj user12: /* Printed Circuit Board (PCB) */

2018-05-27T04:03:41Z

‎Printed Circuit Board (PCB)

@@ Line 516: / Line 516: @@
 === Project Video ===
-* [https://youtu.be/Qx3vNtHbZyU XY_plotter video]
+* [https://youtu.be/9pdz0mTtlDQ XY_plotter video]
 === Project Source Code ===

@@ Line 319: / Line 319: @@
-The bracket holding the pen in place can be moved up and down vertically using a servo motor. This mimics picking up the pen during drawing or writing by hand. A SG90 9g digital servo motor is used for this. PWM input for the servo motor is given from pin P2.2 configured as PWM output on the SJ One Board.
+The bracket holding the pen in place can be moved up and down vertically using a servo motor. This mimics picking up the pen during drawing or writing by hand. A SG90 9g digital servo motor is used for this. PWM output for the servo motor is given from pin P2.1.
 For pen down, a PWM pulse of 1.5ms at 50 Hz, servo motor stays at the neutral position or 0°, the pen comes in contact with the surface and the plotter starts drawing.
 For pen up, a PWM pulse of 2ms at 50Hz is input, servo motor rotates right.

@@ Line 292: / Line 292: @@
 *Calculation of steps:
 The belt moves along the circumference of the pulley connected with the stepper motor shaft.
-As per the figure 1 calculation, for one complete rotation of the stepper motor, the belt will move at a distance equivalent to 32mm.
+As per the figure 7 calculation, for one complete rotation of the stepper motor, the belt will move at a distance equivalent to 32mm.
 i.e. 360° rotation = 32mm linear movement.
 Therefore, one step which is equal to 1.8° will move the plotter by a distance of (32/360°)*1.8°= 0.16mm. Now, as an example, 100mm linear movement along X or Y axis would require 100/0.16 steps which are equal to 625 steps or pulses.

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 === '''System Overview and Mechanism''' ===
 The XY plotter machine is based on a mechanism similar to H-bot where the two motors responsible for XY movements are on the main chassis, which keeps the center of gravity closer to the chassis for a better stability. Graphic animation of the mechanism used in the project is shown in figure 2 where linear motions of the violet slider along X and Y axes are controlled by orange and green driving pulleys depicting two stepper motors. The violet slider has a pen connected at the front.
- The movement of pen based on the motor rotation is shown in figure 3. Based on the front view in figure 1, M1 and M2 represent two stepper motors on the left and right of the machine and the direction arrows shows the direction of the pen. For example to move the pen in the left direction on the X-axis, both the stepper motor should rotate in a clockwise direction with the same speed.
+The movement of pen based on the motor rotation is shown in figure 3. Based on the front view in figure 1, M1 and M2 represent two stepper motors on the left and right of the machine and the direction arrows shows the direction of the pen. For example to move the pen in the left direction on the X-axis, both the stepper motor should rotate in a clockwise direction with the same speed.
 <center>
 <table>

@@ Line 197: / Line 197: @@
 === '''System Overview and Mechanism''' ===
 The XY plotter machine is based on a mechanism similar to H-bot where the two motors responsible for XY movements are on the main chassis, which keeps the center of gravity closer to the chassis for a better stability. Graphic animation of the mechanism used in the project is shown in figure 2 where linear motions of the violet slider along X and Y axes are controlled by orange and green driving pulleys depicting two stepper motors. The violet slider has a pen connected at the front.
-The movement of pen based on the motor rotation is shown in figure 3. Based on the front view, M1 and M2 represent two stepper motors on the left and right of the machine. For example to move the pen in the left direction on the X-axis, both the stepper motor should rotate in a clockwise direction with the same speed. The movement of pen based on the motor rotation is shown in figure 3. Based on the front view in figure 1, M1 and M2 represent two stepper motors on the left and right of the machine and the direction arrows shows the direction of the pen. For example to move the pen in the left direction on the X-axis, both the stepper motor should rotate in a clockwise direction with the same speed.
+ The movement of pen based on the motor rotation is shown in figure 3. Based on the front view in figure 1, M1 and M2 represent two stepper motors on the left and right of the machine and the direction arrows shows the direction of the pen. For example to move the pen in the left direction on the X-axis, both the stepper motor should rotate in a clockwise direction with the same speed.
 <center>
 <table>

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 == '''Conclusion''' ==
-This project has been a great experience in a way where we learned different hardware interfacing with the SJone board. During the project period, we came across many challenges as discussed above and tried to solve the same. The plotter was able to make a 2D figure given from the sd card. Through this project, we have learned the application of GPIO and PWM to the motors, interfacing SPI to read from SDcard, configuring interrupt, PCB designing and use FreeRtos API in a project.
+This project has been a great experience in a way where we learned different hardware interfacing with the SJone board. During the project period, we came across many challenges as discussed above and tried to solve the same. The plotter was able to make a 2D figure given from the sd card. Through this project, we have learned the followings:
 === Project Video ===

@@ Line 226: / Line 226: @@
 <li style="display: inline-block;"> [[File:Cmpe244_S18_Watchdog_PCB_board.png|center|1200px|thumb| '''Figure 4. PCB board layout''']] </li>
-<li style="display: inline-block;"> [[File:CMPE244 S18 schemetic and actual PCB.png|center|1200px|thumb| '''Figure 5. Schematic ''']]</li>
+<li style="display: inline-block;"> [[File:CMPE244 S18 schemetic and actual PCB.png|center|1200px|thumb| '''Figure 5. PCB Schematic and Fabricated PCB ''']]</li>
 </ul></div>

@@ Line 470: / Line 470: @@
 * For a full step configuration, Vref was adjusted to 0.7V.
-=== Erroneous movement of stepper motor using PWM ===
+=== Erroneous movement of stepper motor using PWM pins output===
 * Stepper motors were initially interfaced with the PWM outputs. However, there was no accuracy of the number of steps taken by the stepper since it requires a precise timing control to stop it at a given step or position.
 * Also, since all the PWM channels have the same frequency at a given time, therefore we had an issue providing different frequencies to the two stepper motors.

@@ Line 223: / Line 223: @@
 *one 17 X 2, one 10 X 2 and one 8 X 1 pin connector for GPIO, 3.3V and GND from SJOne board
 Track width for the signal is 0.016 mm and for the power signal, it is 0.024 mm. Package library of the A4988 driver was imported from the Sparkfun. The PCB design is then sent to PCB manufacturer with Gerber file.
-<li style="display: inline-block;"> [[File:Cmpe244_S18_Watchdog_PCB_board.png|center|1200px|thumb| '''Figure 4. PCB board layout''']]
+<div><ul>
-<li style="display: inline-block;"> [[File:Cmpe244 S18 PCB schemetic.jpg|center|1200px|thumb| '''Figure 5. PCB schematic''']]
+<li style="display: inline-block;"> [[File:Cmpe244 S18 PCB schemetic.jpg|center|1200px|thumb| '''Figure 5. PCB schematic''']]</li>
 === '''Hardware Design''' ===