Saturday, May 06, 2006

Base Ideas: Optical Tracking

Sometimes ideas just pop in. Here's one for a basic optical beacon tracker that can possibly operate over extended ranges.

An optical tube (possible zoom, definitely close to focused to "infinity") has an array of IR phototransitors/photodiodes at one end. The target has an IR beacon (IR transmitter, probably driven by a fixed rate PWM from a microcontroller). By either just tracking which transistors are on, or in a more advanced variant, how much energy each sensor "reads" from the target (or if too many see it), the direction that the assembly has to be turned can be calculated. Power levels help to determine the "zoom" of the optics (if fitted). The PWM'ed signal allows either a hardware or software filter to be constructed to look specifically for the PWM signal (similar to the carrier frequency used in IRDA)


Anonymous said...

I like your blog and Im surprised noone else comes here. Keep going, mate.

Im just designing my first analog circuit right now. Its just a simple two transistor amp(to be interfaced with a micro, ofcourse) to work with a photodiode for an IR rangefinder. For robotics and automotive apps.

In fact, I first found this place a few weeks back when I googled for something related to IR.

[Prefer to remain anonymous for now but you can call me PICture. Heh. A pseudonym for a pseudonym... paranoia? Dunno :)]

Mike said...

I am envisioning a telescope?

Is this what you where describing for physical layout?

Anonymous said...

Well, atleast now I know why there are no comments here. Happy experimenting.

AP said...

Take a look at what an optical mouse sensor is capable of.

SOI Sentinel said...

The optics are a telescope. Actually, this idea is partly based upon the theory of tracking used by the TOW missile launcher, where an IR flare is tracked by an auto control system and keeps the missile centered in the crosshairs.