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The
world we live in is a complex place. We have many senses to help us to
understand our surroundings. In order to safely move around robots
also need some way of understanding their world. The easiest way of
doing this is to add simple sensors to you robot.
So,
you've fitted some motors to your robot and its happily driving around
but it probably keeps colliding with obstacles and getting stuck. You
need a way for your robot to detect collisions and move around
objects. Enter the humble bump sensor:
A
bump sensor is probably one of the easiest ways of letting your robot
know it's collided with something. The simplest way to do this is to
fix a micro switch to the front of your robot in a way so that when it
collides the switch will get pushed in, making an electrical
connection. Normally the switch will be held open by an internal
spring.
Micro switches are easy to connect to micro controllers because they
are either off or on, making them digital. All micro controllers are
digital, so this is a match made in heaven. Micro switch 'bump'
sensors are easily connected to the Robocore, simply plug them into
any free digital socket and away you go.
The
following diagram shows a typical circuit for a micro switch bump
sensor. The resistor is important because it holds the signal line at
ground while the switch is off. Without it the signal line is
effectively 'floating' because there is nothing connected to it, and
may cause unreliable readings as the processor tries to decide if the
line is on or off.
Light sensors are perfect for making your robot more interesting. With
some light sensors you can make your robot follow a light, hide in the
dark or even turn on some funky headlights if the light level got a
bit low (under a table for example).
Light sensors are basically resistors that change their value
according to how much light is shining onto them.
They are easy to connect to the Robocore, with a simple circuit they
can be plugged straight into a free analogue socket. Getting results
from them can't be simpler. Get the processor to take a reading from
the socket that the sensors connected to. A high value means not much
light is falling on the sensor; a low value means a lot of light is
falling on the sensor. |
