PPOD-mini Project - Revision history

Ben Tollberg: /* Circuit */

2009-06-15T13:41:25Z

Circuit

Ben Tollberg: /* Overview */

2009-06-15T13:38:58Z

Overview

Ben Tollberg: /* Next Steps */

2009-06-15T13:37:19Z

Next Steps

Ben Tollberg: /* PIC Code */

2009-06-15T13:36:28Z

PIC Code

Ben Tollberg: /* Overview */

2009-06-15T13:34:23Z

Overview

Ben Tollberg: /* Physical Construction */

2009-06-15T13:31:54Z

Physical Construction

Ben Tollberg: /* Speakers */

2009-06-15T13:29:04Z

Speakers

Ben Tollberg: /* Overview */

2009-06-15T13:26:38Z

Overview

Ben Tollberg: /* Circuit */

2009-06-15T12:46:16Z

Circuit

Ben Tollberg: /* Circuit */

2009-06-15T12:45:52Z

Circuit

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 =Circuit=
 [[Image:Ppod mini circuit schematic.JPG|thumb|300px|PPOD-mini Circuit Schematic|right]]
-Each speaker is driven by a combination of four op-amps and a pair of transistors. We used one TLC2274 chip for each speaker because each chip has four separate op-amps and they are able to go rail to rail which simplified our power supply setup. We used two +5V power supplies in series in order to get +/- 5V for the circuit. We are also using a digital potentiometer (Analog Devices AD5206) so we can instantly change the amplitude of each speaker using SPI communication. The circuit diagram is shown to the right. To adjust the setting you press the red button, then using the knob you choose one of three preset patterns or Custom to choose your own phases and amplitudes. If "custom" is chosen you can choose one of 16 settings for the phase and amplitude for each speaker.
+Each speaker is driven by a combination of four op-amps and a pair of transistors. We used one [http://focus.ti.com/lit/ds/symlink/tlc2274.pdf Texas Instruments TLC2274 chip] for each speaker because each chip has four separate op-amps and they are able to go rail to rail which simplified our power supply setup. We used two +5V power supplies in series in order to get +/- 5V for the circuit. We are also using a digital potentiometer ([http://www.analog.com/static/imported-files/data_sheets/AD5204_5206.pdf Analog Devices AD5206]) so we can instantly change the amplitude of each speaker using SPI communication. The circuit diagram is shown to the right. To adjust the setting you press the red button, then using the knob you choose one of three preset patterns or Custom to choose your own phases and amplitudes. If "custom" is chosen you can choose one of 16 settings for the phase and amplitude for each speaker.
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@@ Line 1: / Line 1: @@
 =Overview=
 [[Image:P1000398.JPG|thumb|400px|right]]
-The goal of this project was to create a miniature, simplified version of the PPOD (Programmable Part-feeding Oscillatory Device) that is currently in the Laboratory for Intelligent Mechanical Systems. This smaller model needed to be easily transportable so that it could be taken to various locations and shown to different groups. A video of this device operating while moving parts in a circular pattern can be viewed [http://www.youtube.com/watch?v=DFljiX8js3k here] The PPOD is a device that is able to manipulate parts placed on it by creating a velocity field that is dependent on the phases and amplitudes of the speakers that are connected to the platform. More information on the original PPOD and related research can be found at the [http://lims.mech.northwestern.edu/projects/frictioninducedforcefields/index.htm LIMS website].
+The goal of this project was to create a miniature, simplified version of the PPOD (Programmable Part-feeding Oscillatory Device) that is currently in the Laboratory for Intelligent Mechanical Systems. This smaller model needed to be easily transportable so that it could be taken to various locations and shown to different groups. A video of this device operating while moving parts in a circular pattern can be viewed [http://www.youtube.com/watch?v=DFljiX8js3k here]. The PPOD is a device that is able to manipulate parts placed on it by creating a velocity field that is dependent on the phases and amplitudes of the speakers that are connected to the platform. More information on the original PPOD and related research can be found at the [http://lims.mech.northwestern.edu/projects/frictioninducedforcefields/index.htm LIMS website].
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@@ Line 514: / Line 514: @@
 *Some speakers do not seem to be firing as strongly as others, this makes it difficult to find good patterns.
 *Although +/- 5V are going into the final op-amp, the speakers are only getting +/- 2V maximum. We currently cannot determine the cause for this, however it will make the PPOD-mini much more powerful if it can be fixed.
-*Interfacing the PIC with MATLAB using RS-232 will allow for more complicated patterns to be obtained.
+*Interfacing the PIC with MATLAB using RS-232 will allow for more complicated patterns to be obtained and smoother control.

@@ Line 22: / Line 22: @@
 =PIC Code=
-The following is the PIC code used to control the PPOD-mini with comments.
+The following is the PIC code used to control the PPOD-mini with comments. To operate the LCD screen you need to include the flex_lcd.c file which can be found at [[C Example: Parallel Interfacing with LCDs]]. The only change we made to this code was changing the pins used to D1-D7 instead of the original D0-D6.
  #include <18f4520.h>

@@ Line 1: / Line 1: @@
 =Overview=
 [[Image:P1000398.JPG|thumb|400px|right]]
-The goal of this project was to create a miniature, simplified version of the PPOD (Programmable Part-feeding Oscillatory Device) that is currently in the Laboratory for Intelligent Mechanical Systems. This smaller model needed to be easily transportable so that it could be taken to various locations and shown to different groups. The PPOD is a device that is able to manipulate parts placed on it by creating a velocity field that is dependent on the phases and amplitudes of the speakers that are connected to the platform. More information on the original PPOD and related research can be found at the [http://lims.mech.northwestern.edu/projects/frictioninducedforcefields/index.htm LIMS website].
+The goal of this project was to create a miniature, simplified version of the PPOD (Programmable Part-feeding Oscillatory Device) that is currently in the Laboratory for Intelligent Mechanical Systems. This smaller model needed to be easily transportable so that it could be taken to various locations and shown to different groups. A video of this device operating while moving parts in a circular pattern can be viewed [http://www.youtube.com/watch?v=DFljiX8js3k here] The PPOD is a device that is able to manipulate parts placed on it by creating a velocity field that is dependent on the phases and amplitudes of the speakers that are connected to the platform. More information on the original PPOD and related research can be found at the [http://lims.mech.northwestern.edu/projects/frictioninducedforcefields/index.htm LIMS website].
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@@ Line 5: / Line 5: @@
 =Physical Construction=
+[[Image:Speaker mounts.bmp|thumb|300px|right]]
 ==Base==
 The base for the PPOD-mini is constructed out of acrylic sheets that are approximately 0.22" thick. Each section was designed in AutoCad and then transferred to the [[Laser cutter]] to be created. The sections were designed with a jigsaw pattern on the edges so they would fit together tightly and could be placed exactly where desired. The dimension of the base are 10" x 10" x 3.5". The goal was to keep it as small as possible while still making it functional, this width was required to fit all of the speakers and the height was necessary for the power supplies to fit in the enclosed space. All of the drawing files for these parts can be downloaded at [[Image:PPOD drawing files.zip]].

@@ Line 11: / Line 11: @@
 Six speaker mounts were designed to hold the speakers. They were designed to take up the least amount of space possible while still being stable enough to hold a vibrating speaker for an extended period of time. They were designed similarly to the base, with interlocking acrylic pieces made on the laser cutter and then joined together with a chemical bonding agent. A dimensioned drawing for these pieces is shown on the right.
 ==Speakers==
+[[Image:P1000408.JPG|thumb|300px|left]]
 The speakers used  currently are Jameco 8 ohm speakers, measuring approximately two inches in diameter. When a 5 volt signal is applied these speakers produce 3.125 watts of power. They are secured into the speakers mounts with epoxy. The flexure attachments are epoxied into the center of the speakers and the flexures are held in place by a set screw which is holding on to a threaded rod that runs into the flexure. These flexures are then attached to the platform which is eight inches across and also made of acrylic.
+<br clear=all>
 =Circuit=