Why is mapping useful? Have you ever wanted your robot to navigate through your house, by starting in one room and going in to the next, despite unplanned objects in the way? Ever wanted your robot to go to the fridge, navigate around pizza boxes, and then go straight to you before the beer gets hot?
This tutorial has two parts. The first part demonstrates how the Create can track and follow objects (specifically, a can of beer) using a single Sharp IR. Video in step 5.
The second part demonstrates mapping, and how it can update its map when objects get in the way. Its not just reactive wandering, but planned navigation useful for any house based robot. Video in step 6.
Plans and source code to add to your robot will follow.
So what do you need?
Sharp IR $14.50
Hitec HS-311 Servo $8.99
Grid-Style PC Board with 356 Holes $1.79
36 position breakaway male header $1.63
Stuff you probably have:
solder with soldering iron
double sided sticky tape
two screws with two matching nuts
screwdriver or allen wrench
holepuncher or hand drill
(local hardware store or Radioshack)
Optional: Dremel to cut down the PC Board
Final Design (simplicity at its best):
Step 1: The Stampy Edge Detection Algorithm
To get my Create to perform some complex tasks without requiring huge amounts of memory or processing power, I decided to implement my Stampy Edge Detection algorithm using a scanning Sharp IR rangefinder.
The concept is simple. A scanning Sharp IR rangefinder does only two things:
If no object is seen, the scanner turns right.
If an object is seen, the scanner turns left.
The image of a googley-eyed robot shows the scanner converging on the edge. The robot will then drive towards the detected edge of any object.
This step is to build the scanner.
Here is video instruction on how:
Required parts are shown below.
Now that you have the scanner built, lets wire it up . . .