Difference between revisions of "PPOD-mini Project"

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=Circuit=
=Circuit=
Each speaker is driven by a combination of four op-amps and a pair of transistors. We used ------- 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 ------------- so we can instantly change the amplitude of each speaker individually. 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.

=PIC Code=
=PIC Code=
=Suggestions for Improvement=
=Suggestions for Improvement=

Revision as of 05:08, 15 June 2009

Overview

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 LIMS website.

Physical Construction

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.

Speaker Mounts

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

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 with is eight inches across and also made of acrylic. All of the drawing files for these parts can be downloaded at File:PPOD drawing files.zip.

Circuit

Each speaker is driven by a combination of four op-amps and a pair of transistors. We used ------- 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 ------------- so we can instantly change the amplitude of each speaker individually. 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.

PIC Code

Suggestions for Improvement