However, we have to move beyond that, so let me introduce you to Berry Bot.
For more complicated bots, at some point, we have to
add the ability for it to navigate at least around the house.
We could use a GPS module if we were outdoors, but GPS
modules are fairly useless inside a house or apartment due
to the limited resolution and — even worse — poor GPS
Inside, we can use a variety
of beacons and distance sensors
in order to give the robot an idea
of what room it is in, and how
close it is to nearby objects. That
information is greatly enhanced
by adding a compass. Once we
can tell how far we are from
objects and what direction the
robot is facing, we can start
trying to implement some
mapping functionality which can
later be used for indoor
positioning and navigation.
If we are going to investigate
indoor navigation, it would be
nice to give the robot some more
brain power and the ability to add
more sensors ... which leads to
more batteries and more weight. So, first let’s improve the
An improved drive system needs a more powerful
motor drive, which dovetails rather nicely with talking about
the popular L298N based motor drivers. For this article, I
decided to give Hobbit a holiday and talk about Berry: my
new 4WD Dagu red chassis based bots.
Berry is more “brainy” than Hobbit, and can carry more
weight. Berry currently consists of:
1. Dagu Magician 4WD chassis (red)
2. Raspberry Pi 3
3. RoboPi robot controller
4. L298N driver module
5. HMC5883L magnetometer module (compass)
6. Sharp IR distance sensor
7. 9g servo for panning the Sharp IR sensor
8. Patriot Fuel+ 5,200 mAh USB power bank
9. 4xAA battery holder for
For the time being, Berry will
not be provided with a camera
since vision processing is a very
complicated topic. Plus, a camera
is not necessary for initial indoor
Serving Raspberry Pi
By William Henning
24 SERVO 11.2016
In previous columns, I described my bot,
Hobbit, and had it running around on its
own, avoiding obstacles in a random walk.
Hobbit could also be driven around with a
PS/3 remote control.
PHOTO 2. The Magician 4WD chassis has
plenty of room.