The first speakers in this line were developed as a part of Perry Cook and Dan Trueman’s N-Body project at Princeton University, which studied the emanation of sound in different directions from a variety of musical instruments. The first working models included the full-sphere “Bomb” and the “Boulder”. A slightly later version of a performance rig included “R2”, a spherical speaker built from Ikea salad bowls.
2006-02-14 21:52:00 UTC (Posted by stephan )
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Most sensor interfaces take a range of voltages as input, and convert them into a digital represention. One such interface is the Teabox. If you make your own sensors, or use sensors not perfectly matched to your system, you can usually improve the quality of your data by scaling the voltages into the precise range needed by your interface. In this article the focus will be on using non-nverting op-amps to scale signals for use with the Teabox, but the same principles apply to most other voltage measuring applications as well. Although inverting op-amps are very effective and easy to use, they don’t handle high impedence signals very well (It messes up the gain). If you have a high impedence output you’ll need to use a non-inverting amplifier.
Some sensors send out high impedance signals (roughly meaning that they already have a large resistance on the signal already). This can cause problems with the gain of inverting op-amp designs and severely limit the cable distance a signal can run. Also, some sensors output a signal that doesn’t take up the full range of that the interface can handle. Just one example is Sharp’s line of Infra-Red proximity sensors which send out a high-impedance signal that runs from around 0.7V to 2.8V. No where near the 0.25-4.75V range of the Teabox (or 0-5V range of many other interfaces). A little signal conditioning can improve the data by quite a bit!
There are three generic ways to use a non-inverting amplifier circuit, each of which adds to the functionality by adding a little bit of complexity. All three have the feature of buffering a high impedance input, which is needed to guarantee accurate sensor data. In this article we will concentrate on the first and simplest variety.
The voltage follower is an extremely simple circuit that simply outputs a low impedance voltage that is identical to the input. This would be fairly useless, except that it changes high impedance inputs to low impedance, and makes the signal stronger. Used in conjunction with an inverting op amp, it can be a simple way to condition your signals.
2005-01-11 12:31:00 UTC (Posted by jesse )
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Most sensor interfaces take a range of voltages as input and convert them into a digital represention. One such interface is Electrotap’s Teabox. If you make your own sensors, or use sensors not perfectly matched to your system, you can usually improve the quality of your data by scaling your voltages into the precise range needed by your interface. In this article the focus will be on using Inverting op-amps to scale signals for use with the Teabox, but the same principles apply to most other voltage measuring applications as well. Although Inverting Op-amps are very effective and easy to use, they don’t handle high impedence signals very well (It messes up the gain). If you have a high impedence output you’ll need to use a non-inverting amplifier.
2004-11-01 21:01:00 UTC (Posted by jesse )
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