I need to measure up to 50 feet fairly accurately.
Ultrasonics only does 25 feet.
Any other options?
Laser TOF. It’s expensive, though.
A laser diode isn’t (in current yes).
A single output of the micro to a driver chip can cause the pulse.
A photo transistor as a receiver to an analog in.
Might work
That won’t work, it’s a lot more complex.
You might be able to make a triangulation rangefinder with a laser. I don’t know what accuracy you are looking for, but I would assume by changing the optics (DOF) and offset would adjust how accurate the triangulation method would be.
Dave
This might be interesting:
“Frequency modulation methods involve frequency-modulated laser beams, for example with a repetitive linear frequency ramp. The distance to be measured can be translated into a frequency offset, which may be measured via a beat note of the sent-out and received beam.”
How accurate do you want? I might use a webcam and size up the object and calculate its distance according to its size on the image.
There is another way I saw somewhere but can’t remember. You have two laser spots from the detector shooting apart from each other so that a flat surface with intercept them. Then you can measure the dot separations on the surface to determine distance.
dattaway,
It’s better known as using a heterodyne effect. It’s the same idea as using a superheterodyne receiver, except you have to use optical modulation/demodulation. From what I’ve read, it typically involves varying the intensity of the laser.
I’m attempting to build one for my senior design project. If I get it figured out, I’ll post a link to the team webpage that will explain the design.
James