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Kistaro Windrider, Reptillian Situation Assessor

Unfortunately, I Really Am That Nerdy

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Nerd (n).
nyah, tongueout, glasses, nerd
Nerd: (noun) Any person who chooses to spend perfectly good free time constructing a robot out of a Lego Mindstorms kit for the sole purpose of retrieving presents from under a Christmas tree.

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Yes, but will it work? Wouldn't the legos fall apart quite quickly under the kinetic strain of liftin, pulling, and dragging? You get bonus points if you have either A) considered this, and found a way around it, or B) considered it, and don't really care.

This is a Lego Mindstorms set, actively designed for such use. It has special parts exclusively to add more structural strength; the RoverBot design is wonderful to start from. It supports the RCX (Robotic Control Unit... uhh, not sure what the X is doing there, but whatever Lego wants) quite nicely, and has great traction and power when using the Treads option.

I'm not about to try to do a lifter. Pulling and dragging, yes, but by "pinning" the target and dragging it backwards. The dragger will be carefully anchored to the top of the RCX, with support beams linking to the bottom. The motor will power one long arm, which branches out at the top into a "T" shape (with a bend in it to make it easier to get a grip, and a plastic hose at the top to act as a softer "spring" to not damage the item- which is actually what the hoses are for), and has a single-bumper touch sensor at the front to tell when it bumps into something.

I'll program it in NQC (Not Quite C) instead of RCXbrix, as the basic point-click-curse interface of RCXbrix is not what I, as a decent programmer, like. The program will use two inputs- touch sensors A and B. B is the bumper; A is a loose sensor used as a "button" for entry. Since I'm using NQC, I can directly affect the display (which RCXbrix cannot do in RIS 1.5, even with the firmware upgrade- in fact, only NQC and ASM get any benifit from the 2.0 upgrade, unless you have a full RIS 2.0 kit with the new software) to show what the program will do. And NQC has automatic double-click detection! Click slowly to scroll through the speeds for motor 1 (left), then double-click to accept; do the same for motor 3, and then double-click to Go or single-click to Retry. The display will show a three digit number- the left digit as the speed (0-8) of motor A, right digit as the speed of motor B, and center digit as an indicator for what you're inputting- 8 if running, 1 if setting motor A, 2 if setting motor B, 0 if asking for confirmation to run.

After setting the motor speeds and telling the robot to Go, the robot will turn both motors forward at the selected speeds. Zero is a stop; one through eight are slow to turbo. By setting the motors to different speeds, the robot can be made to go in a curve- or a circle.

If the bumper on the front hits something, the robot will stop, beep, lower the arm, and keep pushing down with the arm while reversing both motors and re-activating them at the same speeds to (approximately, this is just Lego after all) retrace its path back to the sender, who pushes the button to stop the robot, and cause it to lift and then loosen its arm (a motor can be running, locked, or loose- locked is not moving and difficult to move from outside force, loose can be moved by hand if need be- another feature of NQC), and wait for reprogramming.

In other words, it's all planned out.

Damn, I want one now.

(Reposted due to an HTML error)

Well, you can get the Lego Mindstorms RIS2 (Robotics Invention System 2.0) for under $250.00 (um... ouch) at Wal-Mart. (I got my RIS 1.5 for two Christmases ago.) It's cheaper than a PlayStation2, and you can make it do what you want instead of having to buy more games for it!

...uhh, yeah.

Anyway, if you're interested and you have an RIS2, build (by the included Constructopedia) a Roverbot with:

-Single bumper, placed on the BACK of the robot (this entire robot moves backwards relative to the RCX, because of where the pieces are)

I'll see if I can't get pictures in enough detail for reconstruction of the arm attachment; as it requires a third motor not included in the basic RIS, the RoboSports expansion set, with its extra motor, is required to construct the RetrievalBot.

I'll share my plans, but it's sort of a do-it-yourself thing. ];=8)

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