KimBot 1 is a
Radio-Controlled car that has an onboard computer that
expands its feature. The Computer is a Parallax Basic
Stamp 2, and is programmed in PBasic.The Car used is the
Grasshopper RC Car, with the included forward/reverse
electronic speed control, and standard Futaba servos.
The user controls the car via a 5 channel 2.5Ghz Radio,
of which 3 channels are used. Channel 1 is
forward/reverse, 2 is for steering and 3 is for the mode
selector.
KimBot 1 Primary features:
Automatic Drive Mode
Assisted Drive
Mode
Computer Off Mode
Low cost (Under $400)
One Sensor
Main Program
Computer-off Mode When the user has selected computer off mode, the
data from the radio is sent directly to the servo and
speed control, without any additional processing. The
Ping sensor is not active, and the user must reboot the
car to return to computer mode.
To enter computer off mode, the user holds the
push-button wile turning the car on, or resetting the
computer. The program checks the state of the
push-button at startup only.
Program 1: Computer-Assisted Drive Mode
The user selects assisted drive mode to help control the
car better when objects are close, or the vehicle is
traveling at a high rate of speed.
1. Computer reads pulse from the radio 2. If the user has selected reverse mode, then the
reverse is initialized, so the user will not have to do
a double back on the stick to reverse. 3. Based on data from the radio, the ping sensor will be
turned into the turn to read ahead of the vehicle. 4. Data is read from the ping sensor to detect objects
in front of it, and if there is no data from the sensor,
the programs defaults to an error mode, stops, and beeps
high to low. If an object is detected in fron of the
vehicle, wile the user control is at max forward speed,
then the computer will govern the forward speed, slower
and slower until it stopps, in front of the object. If
the user uses a slower mode, then the vehicle will roll
up the object. 5. if an object is detected in front of the vehicle that
is less than 15”, and the user has the throttle at max,
then the car trys to break before colliding with an
object. 6. If the user has instructed max forward speed, then
the stering range is limited, to help prevent
overstoring. 7. if no errors have occurred, and there is not any
objects detected in front of the vehicle, then the car
will move exactly as instructed by the user. 8. The computer reads channel 3 to see if the program
mode has changed.
Program 2: Automatic Drive Mode
When the user has selected this mode the vehicle will
scan the room, and move into the most open space. If the
vehicle has gotten too close to an object, then it will
try to back-away from the object, and resume its forward
travel into its perception of open space.
1. Operate sensor in scanning motion, and record 3
distances into memory. If no data is received from the
sensor then default to error mode.
2. Set forward speed based on reading from center ping.
3. Close object detection, back away if an object is too
close in front or on the sides of the vehicle. If object
of less then 15” will trip, will reverse to 30”
4. If no close objects are detected, then the
measurements are comapired, and the vehicle moves in the
direction of the most space.
5. If the car is traveling at a low rate of speed, then
the turn is increased.
6. The computer reads channel 3 to see if the program
mode has changed.
Under the hood
This image shows KimBot1 with the
top removed. It has a very simple design which uses
off-the-shelf components available from Parallax and
your local hobby store.
