![]() The AMBI’s 3-pin interface can mount directly into the analog input of a JeeNode, into the analog block of a BBB, or into the analog pins on an Arduino (since the sensor draws under a milliamp the other two pins are used to provide power). We have cooked up a sensor board called “ AMBI” (for ambient light sensor) that carries a Sharp GA1A1S201WP surface-mount ambient light sensor. I believe that technique will work beautifully with these sensors. In the past it was impossible to “equalize” two sensors, say for light seeking, or line following, just by adding or subtracting a constant amount. No longer will your robots be blind when they roll into a dark corner, or when you take them outside for a walk in the sun. Other values are in between, in a nice even manner. When it’s in an extremely dark room, it reads zero on the Arduino’s 10 bit A/D, when it’s taken outside into direct sunlight it reads around 960 (which is not even saturated yet – maybe in the tropics it would hit 1023). So to cut to the chase, I was really excited when I found this Sharp chip, with a built-in log amp, which behaves the way I think most light sensors should. But until recently I haven’t been able to find a light sensor with a logarithmic response curve the useful TAOS sensor line doesn’t even include one. Which also explains why the F-stop scale on cameras, and the Decibel scale for sound, are both logarithmic scales. This is because the way human eyes see light -– and incidentally the way the human ears hear sound –- is logarithmic. No light sensor that I have used seems to output numbers the same way I see light and shadow – until now. In robotics for example, sensors either tend to saturate in dark corners under tables, or else in bright sunlight when they go for walks outside, rendering the robot blind. If you use photo cells or phototransistors, or other light sensors such as the useful TAOS TSL series, you know that every one leaves something to be desired. This is a light sensor that I’ve been waiting for, for a long time. ![]() Arduino Tutorial Online Courses Video Training.Arduino Nano Projects List in PDF offline downloadable. ![]()
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