https://hades.mech.northwestern.edu//index.php?action=history&feed=atom&title=Microphones 2026-05-27T16:36:36Z Revision history for this page on the wiki MediaWiki 1.43.8 https://hades.mech.northwestern.edu//index.php?title=Microphones&diff=7187&oldid=prev 2008-03-02T22:39:06Z

<p></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 17:39, 2 March 2008</td> </tr><tr> <td colspan="2" class="diff-lineno">Line 1:</td> <td colspan="2" class="diff-lineno">Line 1:</td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><br /></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Overview ==</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Overview ==</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> </table>

Lynch https://hades.mech.northwestern.edu//index.php?title=Microphones&diff=7186&oldid=prev 2008-03-02T22:38:37Z

<p></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 17:38, 2 March 2008</td> </tr><tr> <td colspan="2" class="diff-lineno">Line 1:</td> <td colspan="2" class="diff-lineno">Line 1:</td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>== Original Assignment ==</div></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><br /></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>This project is to demonstrate a "clapper" device using an electret microphone (e.g., the 423-1024-ND from digikey). Build an appropriate circuit and write a program to continuously display the volume of the sound it receives as a "light bar" on the PIC board LEDs.</div></td> <td colspan="2" class="diff-empty diff-side-added"></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Overview ==</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Overview ==</div></td> </tr> </table>

Lynch https://hades.mech.northwestern.edu//index.php?title=Microphones&diff=7150&oldid=prev 2008-02-21T05:07:01Z

<p><span class="autocomment">Circuit</span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 00:07, 21 February 2008</td> </tr><tr> <td colspan="2" class="diff-lineno">Line 27:</td> <td colspan="2" class="diff-lineno">Line 27:</td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The circuit built for this example uses an electret microphone to listen to external sound and displays the volume level as a light bar on the PIC board LEDs. The microphone uses a single analog input pin of the PIC.</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The circuit built for this example uses an electret microphone to listen to external sound and displays the volume level as a light bar on the PIC board LEDs. The microphone uses a single analog input pin of the PIC.</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Optional features present in the shown circuit diagram include a potentiometer gain knob for adjusting the microphone's sensitivity and a calibration button for setting the baseline ambient noise level. The code governing the operation of the calibration button is included below; the button itself is wired into a digital input of the PIC. Refer to the photo and diagram for details.</div></td> <td class="diff-marker" data-marker="+"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Optional features present in the shown circuit diagram include a potentiometer gain knob for adjusting the microphone's sensitivity and a calibration button for setting the baseline ambient noise level. The code governing the operation of the calibration button is included below; the button itself is wired into a digital input of the PIC. Refer to the photo and diagram for details<ins style="font-weight: bold; text-decoration: none;">. Although the potentiometer is good for calibration, we found that we can get a decent sensitivity by simply using a 2.2K-ohm resistor</ins>.</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> </table>

JeremyDarling https://hades.mech.northwestern.edu//index.php?title=Microphones&diff=7149&oldid=prev 2008-02-21T04:57:50Z

<p></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 23:57, 20 February 2008</td> </tr><tr> <td colspan="2" class="diff-lineno">Line 21:</td> <td colspan="2" class="diff-lineno">Line 21:</td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>We ran into several problems using this configuration, and other configurations similar to this one. First of all, the sensitivity of the microphone was poor even at the most sensitive potentiometer setting. Because of the way the code worked, we were able to register a loud clap within about a foot of the microphone, but we weren't able to get a good response from a constant sound, like a hum. This would work well for a device that just needed to register when a loud noise occurs, but would not be suitable for any sort of recording or signal processing.</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>We ran into several problems using this configuration, and other configurations similar to this one. First of all, the sensitivity of the microphone was poor even at the most sensitive potentiometer setting. Because of the way the code worked, we were able to register a loud clap within about a foot of the microphone, but we weren't able to get a good response from a constant sound, like a hum. This would work well for a device that just needed to register when a loud noise occurs, but would not be suitable for any sort of recording or signal processing.</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Another approach we tried was to run the signal through a simple non-inverting operational amplifier. This was even less successful as it amplified the noise to the level where a clap or hum was indistinguishable from the noise. We experimented with a gain of 2 and a gain of 11. The gain of 2 made no significant difference and the gain of 11 simply amplified too much noise.</div></td> <td class="diff-marker" data-marker="+"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Another approach we tried was to run the signal through a simple non-inverting<ins style="font-weight: bold; text-decoration: none;"> [[Operational Amplifiers (Op-Amps) |</ins> operational amplifier<ins style="font-weight: bold; text-decoration: none;">]]</ins>. This was even less successful as it amplified the noise to the level where a clap or hum was indistinguishable from the noise. We experimented with a gain of 2 and a gain of 11. The gain of 2 made no significant difference and the gain of 11 simply amplified too much noise.</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Circuit ==</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Circuit ==</div></td> </tr> </table>

JeremyDarling https://hades.mech.northwestern.edu//index.php?title=Microphones&diff=7148&oldid=prev 2008-02-21T04:41:51Z

<p></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 23:41, 20 February 2008</td> </tr><tr> <td colspan="2" class="diff-lineno">Line 16:</td> <td colspan="2" class="diff-lineno">Line 16:</td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Of the three microphones tested for the clapper device (Electret Microphone, [http://www.sonystyle.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10551&amp;storeId=10151&amp;langId=-1&amp;productId=11037550 Sony F-V100], and a small dynamic microphone), the electret microphone showed the greatest sensitivity to varying noise levels.</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Of the three microphones tested for the clapper device (Electret Microphone, [http://www.sonystyle.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10551&amp;storeId=10151&amp;langId=-1&amp;productId=11037550 Sony F-V100], and a small dynamic microphone), the electret microphone showed the greatest sensitivity to varying noise levels.</div></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>=== Problems ===</div></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>We ran into several problems using this configuration, and other configurations similar to this one. First of all, the sensitivity of the microphone was poor even at the most sensitive potentiometer setting. Because of the way the code worked, we were able to register a loud clap within about a foot of the microphone, but we weren't able to get a good response from a constant sound, like a hum. This would work well for a device that just needed to register when a loud noise occurs, but would not be suitable for any sort of recording or signal processing.</div></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td colspan="2" class="diff-empty diff-side-deleted"></td> <td class="diff-marker" data-marker="+"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Another approach we tried was to run the signal through a simple non-inverting operational amplifier. This was even less successful as it amplified the noise to the level where a clap or hum was indistinguishable from the noise. We experimented with a gain of 2 and a gain of 11. The gain of 2 made no significant difference and the gain of 11 simply amplified too much noise.</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Circuit ==</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Circuit ==</div></td> </tr> </table>

JeremyDarling https://hades.mech.northwestern.edu//index.php?title=Microphones&diff=7061&oldid=prev 2008-02-19T23:45:01Z

<p><span class="autocomment">Overview</span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 18:45, 19 February 2008</td> </tr><tr> <td colspan="2" class="diff-lineno">Line 13:</td> <td colspan="2" class="diff-lineno">Line 13:</td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:&lt;math&gt;Q = C \cdot V&lt;/math&gt; where Q = charge in coulombs, C = capacitance in farads and V = potential difference in volts, resulting in a change in output voltage. Power is necessary for establishing the capacitor plate voltage, and is also needed for internal amplification of the signal to a useful output level. Electret microphones, a type of condenser microphone, replace the externally-applied charge with a permanently fixed-charged material. The electret is a stable dielectric material with a permanently-embedded static charge. Electret microphones require no polarizing voltage but, due to their integrated pre-amplifier, require a small amount of power either from microphone inputs as phantom power or from a small battery. Due to mass-production of these devices, electret microphones lack the precision needed for high-quality microphones.</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>:&lt;math&gt;Q = C \cdot V&lt;/math&gt; where Q = charge in coulombs, C = capacitance in farads and V = potential difference in volts, resulting in a change in output voltage. Power is necessary for establishing the capacitor plate voltage, and is also needed for internal amplification of the signal to a useful output level. Electret microphones, a type of condenser microphone, replace the externally-applied charge with a permanently fixed-charged material. The electret is a stable dielectric material with a permanently-embedded static charge. Electret microphones require no polarizing voltage but, due to their integrated pre-amplifier, require a small amount of power either from microphone inputs as phantom power or from a small battery. Due to mass-production of these devices, electret microphones lack the precision needed for high-quality microphones.</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Due to the variable nature of ambient noise, a calibration "reset" button was included that would reset the output LEDs based on the environment's baseline noise level. This calibration was done via software averaging of the ambient volume level. The device that is built currently follows the principles of the <del style="font-weight: bold; text-decoration: none;">"</del>clapper<del style="font-weight: bold; text-decoration: none;">"</del> device in that the higher the analog input is received, the more LEDs will be shown. However, due to the brevity of the audio input peak for shorter signals such as a clap, it is sometimes difficult to see the correspondingly brief output. A further step would be to install a software switch that would detect the characteristic sound pattern of a clap and activate a digital output upon recognition.</div></td> <td class="diff-marker" data-marker="+"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Due to the variable nature of ambient noise, a calibration "reset" button was included that would reset the output LEDs based on the environment's baseline noise level. This calibration was done via software averaging of the ambient volume level. The device that is built currently follows the principles of the clapper device in that the higher the analog input is received, the more LEDs will be shown. However, due to the brevity of the audio input peak for shorter signals such as a clap, it is sometimes difficult to see the correspondingly brief output. A further step would be to install a software switch that would detect the characteristic sound pattern of a clap and activate a digital output upon recognition.</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Of the three microphones tested for the clapper device (Electret Microphone, [http://www.sonystyle.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10551&amp;storeId=10151&amp;langId=-1&amp;productId=11037550 Sony F-V100], and a small dynamic microphone), the electret microphone showed the greatest sensitivity to varying noise levels.</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Of the three microphones tested for the clapper device (Electret Microphone, [http://www.sonystyle.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10551&amp;storeId=10151&amp;langId=-1&amp;productId=11037550 Sony F-V100], and a small dynamic microphone), the electret microphone showed the greatest sensitivity to varying noise levels.</div></td> </tr> </table>

AlexanderLeung https://hades.mech.northwestern.edu//index.php?title=Microphones&diff=7060&oldid=prev 2008-02-19T23:44:41Z

<p><span class="autocomment">Overview</span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 18:44, 19 February 2008</td> </tr><tr> <td colspan="2" class="diff-lineno">Line 15:</td> <td colspan="2" class="diff-lineno">Line 15:</td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Due to the variable nature of ambient noise, a calibration "reset" button was included that would reset the output LEDs based on the environment's baseline noise level. This calibration was done via software averaging of the ambient volume level. The device that is built currently follows the principles of the "clapper" device in that the higher the analog input is received, the more LEDs will be shown. However, due to the brevity of the audio input peak for shorter signals such as a clap, it is sometimes difficult to see the correspondingly brief output. A further step would be to install a software switch that would detect the characteristic sound pattern of a clap and activate a digital output upon recognition.</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Due to the variable nature of ambient noise, a calibration "reset" button was included that would reset the output LEDs based on the environment's baseline noise level. This calibration was done via software averaging of the ambient volume level. The device that is built currently follows the principles of the "clapper" device in that the higher the analog input is received, the more LEDs will be shown. However, due to the brevity of the audio input peak for shorter signals such as a clap, it is sometimes difficult to see the correspondingly brief output. A further step would be to install a software switch that would detect the characteristic sound pattern of a clap and activate a digital output upon recognition.</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Of the three microphones tested for the clapper device(Electret Microphone, [http://www.sonystyle.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10551&amp;storeId=10151&amp;langId=-1&amp;productId=11037550 Sony F-V100], and a small dynamic microphone), the electret microphone showed the greatest sensitivity to varying noise levels.</div></td> <td class="diff-marker" data-marker="+"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Of the three microphones tested for the clapper device<ins style="font-weight: bold; text-decoration: none;"> </ins>(Electret Microphone, [http://www.sonystyle.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10551&amp;storeId=10151&amp;langId=-1&amp;productId=11037550 Sony F-V100], and a small dynamic microphone), the electret microphone showed the greatest sensitivity to varying noise levels.</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Circuit ==</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Circuit ==</div></td> </tr> </table>

AlexanderLeung https://hades.mech.northwestern.edu//index.php?title=Microphones&diff=7059&oldid=prev 2008-02-19T23:44:32Z

<p><span class="autocomment">Overview</span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 18:44, 19 February 2008</td> </tr><tr> <td colspan="2" class="diff-lineno">Line 15:</td> <td colspan="2" class="diff-lineno">Line 15:</td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Due to the variable nature of ambient noise, a calibration "reset" button was included that would reset the output LEDs based on the environment's baseline noise level. This calibration was done via software averaging of the ambient volume level. The device that is built currently follows the principles of the "clapper" device in that the higher the analog input is received, the more LEDs will be shown. However, due to the brevity of the audio input peak for shorter signals such as a clap, it is sometimes difficult to see the correspondingly brief output. A further step would be to install a software switch that would detect the characteristic sound pattern of a clap and activate a digital output upon recognition.</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Due to the variable nature of ambient noise, a calibration "reset" button was included that would reset the output LEDs based on the environment's baseline noise level. This calibration was done via software averaging of the ambient volume level. The device that is built currently follows the principles of the "clapper" device in that the higher the analog input is received, the more LEDs will be shown. However, due to the brevity of the audio input peak for shorter signals such as a clap, it is sometimes difficult to see the correspondingly brief output. A further step would be to install a software switch that would detect the characteristic sound pattern of a clap and activate a digital output upon recognition.</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Of the three microphones tested (Electret Microphone, [http://www.sonystyle.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10551&amp;storeId=10151&amp;langId=-1&amp;productId=11037550 Sony F-V100], and a small dynamic microphone), the electret microphone showed the greatest sensitivity to varying noise levels.</div></td> <td class="diff-marker" data-marker="+"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Of the three microphones tested <ins style="font-weight: bold; text-decoration: none;">for the clapper device</ins>(Electret Microphone, [http://www.sonystyle.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10551&amp;storeId=10151&amp;langId=-1&amp;productId=11037550 Sony F-V100], and a small dynamic microphone), the electret microphone showed the greatest sensitivity to varying noise levels.</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Circuit ==</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Circuit ==</div></td> </tr> </table>

AlexanderLeung https://hades.mech.northwestern.edu//index.php?title=Microphones&diff=7058&oldid=prev 2008-02-19T23:42:43Z

<p><span class="autocomment">Overview</span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 18:42, 19 February 2008</td> </tr><tr> <td colspan="2" class="diff-lineno">Line 11:</td> <td colspan="2" class="diff-lineno">Line 11:</td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The most commonly used microphones for audio use capacitance charge (condenser microphones), electromagnetic generation (dynamic microphones), or piezoelectric generation. In a [http://en.wikipedia.org/wiki/Condenser_microphone#Condenser.2C_capacitor_or_electrostatic_microphones condenser microphone], a thin membrane of the microphone acts as one plate of a capacitor and a nearly constant charge is maintained on the capacitor. The voltage maintained across the capacitor plates changes with the vibrations in the air, according to the capacitance equation: </div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The most commonly used microphones for audio use capacitance charge (condenser microphones), electromagnetic generation (dynamic microphones), or piezoelectric generation. In a [http://en.wikipedia.org/wiki/Condenser_microphone#Condenser.2C_capacitor_or_electrostatic_microphones condenser microphone], a thin membrane of the microphone acts as one plate of a capacitor and a nearly constant charge is maintained on the capacitor. The voltage maintained across the capacitor plates changes with the vibrations in the air, according to the capacitance equation: </div></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>:&lt;math&gt;Q = C \cdot V&lt;/math&gt; where Q = charge in coulombs, C = capacitance in farads and V = potential difference in volts, resulting in <del style="font-weight: bold; text-decoration: none;">an</del> <del style="font-weight: bold; text-decoration: none;">electrical</del> <del style="font-weight: bold; text-decoration: none;">signal</del>. Power is necessary for establishing the capacitor plate voltage, and is also needed for internal amplification of the signal to a useful output level. Electret microphones, a type of condenser microphone, replace the externally-applied charge with a permanently fixed-charged material. The electret is a stable dielectric material with a permanently-embedded static charge. Electret microphones require no polarizing voltage but, due to their integrated pre-amplifier, require a small amount of power either from microphone inputs as phantom power or from a small battery. Due to mass-production of these devices, electret microphones lack the precision needed for high-quality microphones.</div></td> <td class="diff-marker" data-marker="+"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>:&lt;math&gt;Q = C \cdot V&lt;/math&gt; where Q = charge in coulombs, C = capacitance in farads and V = potential difference in volts, resulting in <ins style="font-weight: bold; text-decoration: none;">a</ins> <ins style="font-weight: bold; text-decoration: none;">change</ins> <ins style="font-weight: bold; text-decoration: none;">in output voltage</ins>. Power is necessary for establishing the capacitor plate voltage, and is also needed for internal amplification of the signal to a useful output level. Electret microphones, a type of condenser microphone, replace the externally-applied charge with a permanently fixed-charged material. The electret is a stable dielectric material with a permanently-embedded static charge. Electret microphones require no polarizing voltage but, due to their integrated pre-amplifier, require a small amount of power either from microphone inputs as phantom power or from a small battery. Due to mass-production of these devices, electret microphones lack the precision needed for high-quality microphones.</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Due to the variable nature of ambient noise, a calibration "reset" button was included that would reset the output LEDs based on the environment's baseline noise level. This calibration was done via software averaging of the ambient volume level. The device that is built currently follows the principles of the "clapper" device in that the higher the analog input is received, the more LEDs will be shown. However, due to the brevity of the audio input peak for shorter signals such as a clap, it is sometimes difficult to see the correspondingly brief output. A further step would be to install a software switch that would detect the characteristic sound pattern of a clap and activate a digital output upon recognition.</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Due to the variable nature of ambient noise, a calibration "reset" button was included that would reset the output LEDs based on the environment's baseline noise level. This calibration was done via software averaging of the ambient volume level. The device that is built currently follows the principles of the "clapper" device in that the higher the analog input is received, the more LEDs will be shown. However, due to the brevity of the audio input peak for shorter signals such as a clap, it is sometimes difficult to see the correspondingly brief output. A further step would be to install a software switch that would detect the characteristic sound pattern of a clap and activate a digital output upon recognition.</div></td> </tr> </table>

AlexanderLeung https://hades.mech.northwestern.edu//index.php?title=Microphones&diff=7057&oldid=prev 2008-02-19T23:39:02Z

<p><span class="autocomment">Overview</span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 18:39, 19 February 2008</td> </tr><tr> <td colspan="2" class="diff-lineno">Line 5:</td> <td colspan="2" class="diff-lineno">Line 5:</td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Overview ==</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== Overview ==</div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker" data-marker="−"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>A "clapper" device was built using a PIC 18F4520 and an [http://en.wikipedia.org/wiki/Electret_microphone electret condenser microphone] (in this case, the [http://www.knowles.com/search/prods_pdf/MD9745APA-1.pdf 423-1024-ND] from digikey) as an analog input. The device operates on the principle that the microphone will convert the sound into an analog input to the PIC and as the sound increases in volume, the analog input's amplitude will increase. This input is then converted into an output on the set of LEDs soldered onto the PIC's circuit board. This output works as a light bar; it displays the minimum one LED for quiet sound levels and activates additional LEDs as the sound becomes louder -- up to a maximum of eight. The sensitivity of the microphone is adjustable through a gain potentiometer. </div></td> <td class="diff-marker" data-marker="+"></td> <td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>A "clapper" device was built using a PIC 18F4520 and an [http://en.wikipedia.org/wiki/Electret_microphone electret condenser microphone] (in this case, the [http://www.knowles.com/search/prods_pdf/MD9745APA-1.pdf 423-1024-ND] from digikey) as an analog input. The device operates on the principle that the microphone will convert the sound into an analog input to the PIC and<ins style="font-weight: bold; text-decoration: none;">,</ins> as the sound increases in volume, the analog input's amplitude will increase. This input is then converted into an output on the set of LEDs soldered onto the PIC's circuit board. This output works as a light bar; it displays the minimum one LED for quiet sound levels and activates additional LEDs as the sound becomes louder -- up to a maximum of eight. The sensitivity of the microphone is adjustable through a gain potentiometer. </div></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td> </tr> <tr> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[image:ElectretMicrophone.gif|thumb|300px|[[Interior of Electret Microphone]]|right]]</div></td> <td class="diff-marker"></td> <td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[image:ElectretMicrophone.gif|thumb|300px|[[Interior of Electret Microphone]]|right]]</div></td> </tr> </table>

AlexanderLeung