3D location from multiple cameras or an FM radio array

Hi all,

I've had the idea recently to attempt to be able to keep a real-time track of the location of something in a room.

My first thoughts where to use an array of FM receivers and a transmitter to triangulate the location of the transmitter, or maybe even bluetooth, but the test room is about 5 metres square, so bluetooth might be unrealistic.

As for the FM method, I think that could genuinely work, what do you think?

An idea also floated is to triangulate using an array of cameras, maybe all triangulating the location of one infra-red LED light.

What do the geniuses of Instructables think of the ideas here, do you think any are valid?

King regards,


I recommend using a Microsoft Kinect. It has built-in depth perception like the Wii but doesn't require a remote. Start with this video. You can use OpenCV to do the tracking; it will require some programming ability on your end.
For IR tracking you should check out Johnny Lee's work with the Wiimote. There's an IR camera in the Wiimote that is used for detecting IR reference points in the sensor bar and can be connected to a computer via Bluetooth. The site is http://johnnylee.net/projects/wii/ Unfortunately he hasn't gotten to 3D tracking. I haven't look much past that page but other people may have continued the work and if not, there's plenty of information to get you started toward your own solution.
kelseymh5 years ago
These ideas are definitely valid, but may be more complex than you think they are. If you haven't done so already, you might want to do a literature search (Google Scholar is what I use) on your topic. Don't use the word "triangulation," which pulls up almost entirely hits for adaptive-mesh and finite-element analysis systems (i.e., converting a smooth surface into triangles).

For an FM system, you're going to be dealing with a broadcasting (isotropic) beacon. That means you'll either need software to compare the signal strengths, and receivers with mutually calibrated amplifiers so the results can be compared accurately; or you'll need more complex steerable directional antennas (such as a phased array).

For the IR system, you'll need at least some kind of image recognition software, along with software to correlate the known camera orientation with the position of the IR spot on the image plane to get an absolute direction.

Like I said, your ideas are quite valid, but complex. I think my notes above should give you enough keywords to start doing research on your own around the specific problems you'll solve along the way. Good luck!