How to attach physical sensors to computers? (infrared, laser)

I am working on a project where I need to attach a sensor to the computer like laser开发者_运维百科 sensor or an infrared sensor, to use in a foul line detection. Basically the idea is, if someone steps on the foul line, the laser or infrared will be blocked by person's foot, and the laser/infrared won't be received by the receiver, causing the sensor to send a signal to the computer.

The problem is, I don't know where to start something like this. How would I go about attaching a sensor to a normal computer (like a normal PC that we use)? If someone could direct me into a direction or has any inputs, that would be really appreciated. Thanks a lot!

You may want to look at Arduino (http://www.arduino.cc/). It is an open-source microcontroller that can be used along with a computer and is designed to be hooked up to various types of sensors. It also has an extremely helpful, active support community.

There are several approaches to the task of bringing the sensor signal into a PC (to take advantage of PC's computing power, good user interface, connectivity to the web).

• Look for integrated sensors that have an interface for attaching to a PC (RS-232, USB, Ethernet). For example, you may find something useful by googling photodetector USB.

• There are I/O (input/output) devices for PC. They have analog and digital inputs and outputs. Look up LabJack, National Instruments USB-6008 and dozen other types of commercial USB I/O boxes.

• Connect sensors to a microcontroller (uC), then connect uC to the PC through a USB or RS-232 or Bluetooth (the list goes on). This involves more hardware. You'll need to write firmware for the microcontroller too.

Obviously, which approach to choose depends on your skills (or willingness to acquire new ones), timing, budget, team structure (if it's a team effort).

You could use a photo-transistor and a Yocto-Knob. The Yocto-knob is an USB device able to quickly detect resistivity changes, you just have to connect the photo-transistor to it. Here is an application which looks pretty similar to yours: they use a light barrier to detect and photograph a fast object:

http://www.yoctopuce.com/EN/article/how-to-drive-a-camera-shutter-automatically