By now, you’ve most likely have seen or even played with an ultrasonic distance sensor. They work by emitting a sound, and then listening for the “ping” to return. The sensor can then tell how far an object is away by calculating the time in between. With sound waves traveling at 343.2 meters per second (768 mph), it’s no small task to measure the short time it takes for the sound to be emitted, then hit something a few feet away, and return. Now, imagine trying to do that with light.
Light in comparison moves at a whopping 299,792,458 meters per second (or about 671 million miles per hour). You’re going to have to have a pretty fast finger on a stopwatch to measure the time it takes for light to bounce back from an object a few inches away.
[Paul Bristow] is doing just that with the use of a new Time of Flight (ToF) sensor called the TeraRanger One. Developed in cooperation with CERN, this sensor uses a very narrow beam of light (listed as +/- 2 degrees) to accurately measure the position of an object to a resolution of 5mm, with distances up to 14 meters away. It boasts an impressive update rate of >1000 samples a second, and is very micro-controller friendly with UART, I2C, SPI, and PWM output.
[Paul] and his fellow hackers at the Post Tenebras Lab Hackerspace in Geneva got their hands on this sensor, and in a short time had a ball balancing robot up and running. The crude program is not running a PID controller, so the results seen in the video after the break aren’t that impressive. Also, the sensor isn’t exactly cheap at about $180 USD. Despite that, it will be interesting to see what applications these sensors will be used for. If you have any ideas, leave them in the comments below.
