Microphone Probe 9200008
Uses This high quality microphone can be used to display and study waveforms of sound from: A human voice Any other audible sound found in a student s environment. It is also ideal for speed of sound experiments. Common National and State Standards That Can Be Taught With This Data Collector Describing and measuring properties of matter Describing and measuring forms of energy Characteristics and relationship among air, water, and land Modeling sound Properties of waves NOTE: This product is to be used for educational purposes only. It is not intended for medical, industrial, or mercial applications. 2
General Procedures Collect Data in 3 Easy Steps 1 2 3 Turn the collector on, it s ready to use right out of the box. Use touch screen mands to select desired parameters. Insert the USB drive and press Play and Record. Analyze Data in 3 Easy Steps 1 2 3 Remove USB from data collector unit. Place USB drive in your puter. Open the.csv file in your program of choice. About Plug-in/Excel: RED Chart Add In V 1.00 is patible with Windows from XP to 7 and Excel from 2003 to 2007 Mac OS X 10.2.8 to 10.7 and Excel for Mac from 2004 to 2011 RED Chart Add In installer can be found in the RED USB thumb drive included in the package and on the. website. To install please click on the executable file and follow the installation wizard instructions. 3
Help Screen and Error Code Identification Screen The RED USB contains a Help screen file as well as an Error Code Identification Screen. To Access the Error Code Identification Screen: These screens will assist the user in identifying the error codes that may appear on the main screen. Press the? on the top of the main screen. The error codes will appear. By pressing the top or bottom of the screen, the user will be able to either advance the Error Code Identification Screen page or return to the previous Error Code Identification Screen page f an error code does appear, refer to the RED User Manual for Corrective Actions to follow. To Access The Help Screen File: These screens will assist the user with the General Operation and identify the functions of the icons used on the RED probe Insert the included RED USB into the USB port on the RED Data Collector. Press the? on the top of the main screen. The Help Screen will appear. By pressing the top or bottom of the screen, the user will be able to either advance the Help Screen page or return to the previous Help Screen page. 4
Specifications Microphone Range: 0 to 100 (Normalized values) Accuracy: N/A Resolution: N/A How The Probe Actually Works: A microphone is an acoustic-to-electric transducer that converts sound into an electrical signal. Microphones are referred to by their transducer principle. The type used in RED Microphone is called DC-biased capsule condenser microphone. In a condenser microphone, a diaphragm acts as one plate of a capacitor, and the vibrations produce changes in the distance between the plates. There are two types, depending on the method of extracting the audio signal from the transducer: DC-biased and radio frequency (RF) or high frequency (HF) condenser microphones. With a DC-biased microphone, the plates are biased with a fixed charge (Q). The voltage maintained across the capacitor plates changes with the vibrations in the air, according to the capacitance equation (C = Q\V), where Q = charge in coulombs, C = capacitance in farads and V = potential difference in volts. The capacitance of the plates is inversely proportional to the distance between them for a parallel-plate capacitor. The assembly of fixed and movable plates is called an element or capsule. continued 5
How The Probe Actually Works (continued): RED microphone is a sound sensor giving a direct output voltage somewhat proportional to the sound intensity received at the moment. It is NOT a noise level sensor but is designed to study the properties of sound waves from voices and musical instruments. Typical experiments are: measuring the speed of sound or measuring sound beats. The sampling rate can be very high (RED microphone is able to reach 50,000 s/s). There are NO standard units of measure. RED Microphone unit shows on both numeric display and graph a function of the audio signal amplitude that approximates the intensity of the signal (i.e. volume or acoustic pressure). The function used works basically as an envelope detector. Essentially it is showing the modulus of the sound pressure peak value during a time frame of 500ms. This figure has no unit of measure and it is shown as a percentage (like in the sound power level of a laptop microphone). The.csv files generated during data acquisition, saved on USB thumb drive, (Fig. 2) instead show the sound pressure raw data without any processing in order to allow further analysis (frequency, etc) with excel or other analysis software. Being an acoustic wave values average is zero and samples are symmetric around t-axis. This is the reason why the graphs from unit (Fig. 1) and Excel (Fig. 2) are different even if it is pretty clear that the unit s one shows essentially the modulus of the other one. Fig. 1: RED Microphone Screen Capture Fig. 2: RED Microphone Excel Graph 6
Calibration Instructions No Calibration is Needed Maintenance and Storage No particular maintenance is needed. Store at room temperature. Warranty Info: Full 3-year warranty on all RED Data Collectors 7
TM For further support you can download the full user s manual at. This device plies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received including interference that may cause undesired operation. Exclusively Distributed by: Natural Science wardsci. 800-962-2660 In Canada: wardsci.ca 800-387-7822 sciencekit. 800-828-7777 In Canada: Boreal/Northwest boreal. 800-387-9393 sargentwelch. 800-727-4368 In Canada: sargentwelch.ca 800-727-4368