Sometimes, a person has a reason to track a target. A popular way to do this these days is with a camera, a computer, and software to analyze the video. But, that lends itself more to automated systems, like sentries. What if you want to be able to target something by “painting” it with a laser?
That’s exactly what [Jeremy Leaf] wanted to do, and the results are pretty impressive. He was able to track a .06 milliwatt laser at 2 meters. His design does this using three photodiodes in order to determine the position of a laser spot using triangulation.
Once the location of the laser spot has been determined, it can either simply be reported or it can be tracked. Tracking is achieved with a gimbal setup which updates quickly and accurately. Of course, it can only track the laser if the laser has something to be projected upon. If you need to track something in open 3D space, there are alternatives that would be better suited to the task.



![The kind of travesty that can occur when [Stefan Kiese] doesn't have access to nice project boxes.](https://hackaday.com/wp-content/uploads/2016/07/img_3466.jpg?w=250)



LaserWeb3 supports different controllers and the machines they might be connected to – whether they are home-made systems, CNC frames equipped with laser diode emitters (such as retrofitted 3D printers), or one of those affordable blue-box 40W Chinese lasers with the proprietary controller replaced by something like a 
