PPOD-mini: 6-DOF Shaker - Revision history

Ben Tollberg: /* Circuitry Housing */

2009-03-24T19:37:10Z

Circuitry Housing

Ben Tollberg: /* Team Members */

2009-03-20T20:38:01Z

Team Members

Ankur Bakshi: /* Operation */

2009-03-20T03:03:10Z

Operation

Ankur Bakshi: /* Introduction */

2009-03-20T03:01:22Z

Introduction

Ben Tollberg: /* Circuit Diagram */

2009-03-20T02:43:44Z

Circuit Diagram

Ben Tollberg: /* Circuity Housing */

2009-03-20T02:43:32Z

Circuity Housing

Ben Tollberg: /* Vibrating Plate */

2009-03-20T02:43:22Z

Vibrating Plate

Ben Tollberg: /* Circuit Diagram */

2009-03-20T02:38:12Z

Circuit Diagram

Ben Tollberg: /* Circuit Diagram */

2009-03-20T02:37:03Z

Circuit Diagram

Ben Tollberg: /* Introduction */

2009-03-20T02:30:33Z

Introduction

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-=== Circuity Housing ===
+=== Circuitry Housing ===
 [[Image:PPOD_underside.JPG|thumb|200x200 px|left|Underside of PPOD-mini showing the PIC board and circuit, power strip, and external power supply]]
 The electronics is housed under the baseboard the speaker is mounted to, which is a 12" by 12" piece of black ABS plastic.  The baseboard sits on a wooden platform consisting of three rectangular sides of size 4"x12".  It is constructed so that the baseboard is elevated 4".  The platform sides are connected using hot glue and connected to the baseboard using hot glue.  Holes are drilled in the sides of the platform to feed the speaker wire through.  A fourth side is then added to the platform.  The LCD and keypad are mounted to this fourth side.  The electronics are mounted to the underside of the baseboard and are concealed by the wooden platform.

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 == Team Members ==
+[[Image:Group_23.JPG|thumb|300x300 px|right|From left: Donald Redding, Ankur Bakshi, Ben Tollberg]]
 * Ankur Bakshi (Biomedical Engineering, Class of 2009)
 * Donald Redding (Mechanical Engineering, Class of 2009)
 * Ben Tollberg (Mechanical Engineering, Class of 2009)
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 == Introduction ==

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 When first plugging in the PPOD-mini, the switch to change the speaker's phase is triggered and the text on the LCD is garbled. At this point, we are not sure why this occurs. By pressing the reset button on the PIC board or by pressing buttons on the keypad until readable text appears. To change the phase of a speaker, the switch must be pressed. Then following the instructions on the LCD, press the a number between one and six to select the speaker. Next, press a number between zero and five to choose a phase from 0-300 degrees in 60 degree increments. The increments can be changed by uploading a new program to the PIC. The speakers should then be running.
-Due to mechanical issues, we were not able to produce many patterns. Most patterns were only clear near the edges of the plate, as the speaker's did not produce displacements at the center of the plate. A circular pattern was observed by putting the speakers all out of phase. The speakers were set to 0, 1, 2, 3, 4, and 5 for speakers 1, 2, 3, 4, 5, and 6 respectively. Another somewhat observable pattern involved setting two pairs of nodes (e.g. speakers 1 and 6 and speakers 2 and 3) to phase 0 and the other node (e.g. speakers 4 and 5) to phase 5. This resulted in movement towards speakers 4 and 5.
+Due to mechanical issues, we were not able to produce many patterns. Most patterns were only clear near the edges of the plate, as the speaker's did not produce displacements at the center of the plate. A circular pattern was observed by putting the speakers all out of phase. The speakers were set to 0, 1, 2, 3, 4, and 5 for speakers 1, 2, 3, 4, 5, and 6 respectively. A video of this pattern can be seen [http://www.youtube.com/watch?v=5FXyQ6-JIm4 here]. Another somewhat observable pattern involved setting two pairs of nodes (e.g. speakers 1 and 6 and speakers 2 and 3) to phase 0 and the other node (e.g. speakers 4 and 5) to phase 5. This resulted in movement towards speakers 4 and 5. A video of this pattern can be seen [http://www.youtube.com/watch?v=EzaReGZ9ZR0 here].
 == Mechanical Design ==

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 == Introduction ==
 [[Image:PPOD_mini.JPG|thumb|200x200 px|right|PPOD-mini 6-DOF Shaker]]
-The PPOD-mini is a miniaturized version of the Programmable Part-feeding Oscillatory Device ([http://lims.mech.northwestern.edu/projects/frictioninducedforcefields/index.htm PPOD]) found in the Laboratory for Intelligent Mechanical Systems (LIMS) at Northwestern. The PPOD-mini utilizes six speakers that act like actuators. The speakers are connected to a PVC plate via flexures of tygon and iron. In its current implementation, the phase of the speakers can be controlled independently, giving the device six degrees of freedom. The movement of objects placed on the PVC plate can be controlled by changing the phases of the speakers.
+The PPOD-mini is a miniaturized version of the Programmable Part-feeding Oscillatory Device ([http://lims.mech.northwestern.edu/projects/frictioninducedforcefields/index.htm PPOD]) found in the Laboratory for Intelligent Mechanical Systems (LIMS) at Northwestern. The PPOD-mini utilizes six speakers that act like actuators. The speakers are connected to an acrylic plate via flexures of tygon and iron. In its current implementation, the phase of the speakers can be controlled independently, giving the device six degrees of freedom. The movement of objects placed on the acrylic plate can be controlled by changing the phases of the speakers.
 The PPOD mini measures about 12" x 12" x 8" (length x width x height) and can be plugged into a wall outlet for power. The design utilizes a switch to start the speaker-phase changing algorithm, a keypad for input to change the speaker phases, and an 16x2 line LCD for user interfacing and to output the speaker phases. A PIC 18f4520 provides the computing power. Each speaker is driven by an H-bridge (1 L293D runs two speakers), which is powered by a 10W power supply from Marlin Jones ([http://www.mpja.com/prodinfo.asp?number=17635+PS]). The speakers are 1W, 16 ohm speakers from Jameco.

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 [[Image:Ppod_mini_schematic.jpg|thumb|200x200 px|right|Circuit schematic for PPOD mini project]]
 [[Image:PPOD_circuit.JPG|thumb|200x200 px|right|PIC board and circuit. Some wires go under the board so the connections cannot be seen.]]
-To the right is the complete circuit schematic for our project. The +5V and GND for the L293D chips were supplied by the external power supply. The LCD was powered by the PIC +5V and GND in order to avoid some overheating issues that occurred when they were connected to the external supply. Each L293D chip controlled two speakers, with one full H-bridge for each speaker. The direction that voltage is applied to each speaker is controlled by the high or low signals that are output from the PIC to the H-bridges. A push button is connected to the external +5V and RB0 on the PIC to trigger the external interrupt in the code.<br><br><br><br><br><br><br><br><br><br><br><br>
+To the right is the complete circuit schematic for our project. The +5V and GND for the L293D chips were supplied by the external power supply. The LCD was powered by the PIC +5V and GND in order to avoid some overheating issues that occurred when they were connected to the external supply. Each L293D chip controlled two speakers, with one full H-bridge for each speaker. The direction that voltage is applied to each speaker is controlled by the high or low signals that are output from the PIC to the H-bridges. A push button is connected to the external +5V and RB0 on the PIC to trigger the external interrupt in the code.<br><br><br>
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 == Code ==

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 === Vibrating Plate ===
 [[Image:PPOD_above.JPG|thumb|200x200 px|right|Top view of PPOD-mini showing locations of flexure attachments]]
-The vibrating plate is circular and acrylic plastic.  The diameter of this plate is 8".  In order to connect the plate to the tubing, 6 holes are drilled equally spaced on a circle around the plate approximately half an inch from the plate's outer edge.  Again 1/4" diameter screws are used to connect the tubing.  The screws are fed down through the plate and into the second piece of tubing.  Hot glue was used as necessary on the plate around the screws to ensure that the screws are held in place.  Doing so ensures the vibration is transmitted from the speakers to the plate.<br><br><br><br>
+The vibrating plate is circular and acrylic plastic.  The diameter of this plate is 8".  In order to connect the plate to the tubing, 6 holes are drilled equally spaced on a circle around the plate approximately half an inch from the plate's outer edge.  Again 1/4" diameter screws are used to connect the tubing.  The screws are fed down through the plate and into the second piece of tubing.  Hot glue was used as necessary on the plate around the screws to ensure that the screws are held in place.  Doing so ensures the vibration is transmitted from the speakers to the plate.
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 === Circuity Housing ===