Let's Make Robots!

Has anyone used Longer-distance rangefinders (ie golf Laser Rangefinders)?

Was wondering if anybody had any experience or had seen anything on here about people using longer range laser rangefinders as sensors for their robots. 

As I start to work through how to scale-up my current robot it struck me how limited the hobby LRFs and URFs are on range.  On a large bot those little rangefinders might still be okay for obstacle avoidance, but if I want my robot (a roving sentry) to be able to spot human-sized targets in an outdoor environment, I probably will need a much larger range.  I see laser rangefinders for golf selling for under $50... has anyone tried hacking one of these into a bot on here?

 

Thanks,

Jim

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Sisco's picture

_duplicate removed_

kanejp63's picture

I'm thinking of using just like one of our normal IR or ultrasonic rangefinders, but at a longer distance.  The rangefinder would be mounted on a servo on the front of my robot.

My current setup has a small ultrasonic rangefinder on a servo that pans the 180 degrees in front of the robot, and records the distance at each degree.  Then then servo continues to search by panning back and forth across those 180 degrees and comparing the distance at each degree.  If the current distance doesn't match the recorded distance then the robot knows that someone or something has approached, and will react accordingly by destroying it with a death ray (okay, so maybe its just a laser pointer).

The system works fine in my living room with distances out to a couple meters away, but I'd like to scale the whole system up for airsoft, paintball, or other human-sized weapon use.

Maxhirez's picture

Are you thinking the kind you look through and line up two images?

kanejp63's picture

No, I'm thinking of the kind where you look through the scope, put the crosshairs on your target and push a button which returns a distance that reads inside the reticle. 

Maxhirez's picture
What did you have in mind? And what would do the looking through the scope? I'm not sure I'm following your intent-are you thinking of using it to find the distance to an obstacle or was it using it to find living activity?
Sisco's picture

I think he is talking about a digital golf rangefinder, not an optical one. An optical one requires someone to look through and figure out the range with several marks within the scope. A digital scope will use a laser and will display the range on an lcd inside. I think he wants to wire into the rangefinder to output the range to a microcontroller to react based on the reading.

I am not sure if it's possible. I know my rangefinder (I use for bow hunting) will not allow me to hold the button and sweep it over an area to collect the various ranges. Instead I need to point it at something and hold the button for a moment to get the reading. I then need to let go, aim somewhere else and hold the button again.

Rick

Maxhirez's picture
Either one requires a person to be looking through it to select the point that the distance to is being ranged, right?
Sisco's picture

Well, for the intended use, only because you are needed to aim it at a specific object. If he could make it sweep he would not need to aim it. Just bypass the switch, apply power to turn it on, and then have it sweep via a servo. It would merely read the distances and output the distance to the lcd or if he wired into it, perhaps output to an arduino or other microcontroller.

The problem may be the 'sweep' part, since as I pointed out with mine, you can not hold the button to gather various distances. With mine you would have to rotate the servo a degree and take a reading, rotate another degree and take a reading, etc. etc.

You would then need to output the readings to a microcontroller and if anything was within the set distance it would react however it was programmed. Much like a longrange ping sensor. Laser instead of Ultrasonic.

I see what he is trying to do, but it would be easier if the rangefinder he used could read various ranges when triggered,