Let's Make Robots!

WiiDar lidar lassiters and laser placement (oh yeah, it works)

This might be directed only to Grog and Gareth, but I am open to any thoughts.

My WiiDar is up and running and spitting out super-duper-awesome numbers. However, the fact that the whole sensor assembly is physically on the right side of the robot and the the fact that the laser is on an arm (even further to the side) has led to some problems. Basically, my center-line changes as we move closer and further away from the robot. It is like we are sitting on wrong "part" of the "arc" --like we should be sitting on a pivot, but we are instead sitting on the arm. The simple fact is, that because of the length of the arm and the angle of the laser, well, things are a little funny.

I have thought about a pretty simple solution, or at least one I want to try, but before I start making major hardware changes, I thought I would run it past you guys. What if the camera was on the arm (at an angle) and the laser was pointing straight forward, directly on top of the main pivot. Have you guys ever tried this configuration? --How about the "main pivot" in the center and both the camera and laser on a 1/2 arm each and each with 1/2 the angle?

The last thing I want to do here is damage "good" trying to get "perfect" but this could be a lot "straighter"


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Lets see:

Gotta keep the math precise.

You have reinvented the wheel.

2 arms would probably work, vertical works too.

Your socks don't match.

I love LMR.

Well boys, I think Gareth got this one. Vertical seems to make the most sense in my head right now but the 2-arm is quite interesting to me.

I did get my answer though. The bottom line is that it IS worth it to do a little take-apart and experiment. Gotta make brackets. I love making brackets.

Fool! your socks don't even match!


My head  (& lassiter to-be-continued vehicle) tells me that a center pivot point with camera and laser equal distance from it would yield best result. Why not mount it vertically - (it will still work) and mount it direct on servo horn - i did a similar set up and it meant that i could fix my compass to the top too (now there is a neato combo).

ie with the whole thing pointing forward a maximum focal point angle (say converging to a point from 2.5Meters onto a wall) ....this would line up with the center-line of Walter.

....and it would have to be central to "Walters" front end if you really want every last mm to count...... maybe fixed to his undercarriage (byebye line follower.........i am just saying)

BTW :- Your New 12mw laser spot (burner) is blindingly impressive.

Forgive me if I am missing a point. From what I have seen you have re-invented the sharp IR range finder. The main difference is a narrow beam due to the laser but you are loosing range and blinding small animals. Wouldn't you be better off interfacing your laser with a Sharp sensor rather than using an IR LED?

I tried a variety of configurations until the MK4 - I listed some of the Pros & Cons there http://letsmakerobots.com/node/24259 

Whenever the camera is not attached to the laser, the math becomes a little more complex and the accuracy or resolution varies throughout the sweep.

I believe mounting the pivot 1/2 of the way between the camera and laser would work fine, your calculations might have to change a little.  

Gareth and I knocked the idea around of being able to control the angle which the camera and laser were mounted on the arm itself. They would be parallel for maximum range / minimum resolution and then make them go cross-eyed for minimum range / maximum resolution... 

Put the arm on another arm, so you can the "whole setup" to the other side of the bot :)