SERVO 05.2016 55
Post comments on this section and find any associated files and/or downloads at
Your First Robot
I think it would be a mistake to start with an advanced
expensive configuration. So, I suggest the following
components, and building an expandable starter robot:
1. Dagu Magician 2WD chassis
2. Raspberry Pi Model B or B+
3. Wi-Fi adapter
4. L293D based Pi Droid Alpha controller
5. HC-SR04 based distance sensor
6. Red pan head for HC-SR04
7. 9g Mini servo and holder for pan head
8. USB battery pack
9. 4xAA NimH batteries
I chose these components for simplicity, low cost, and
flexibility. As a matter of fact, I built a robot based on the
specifications above just before sending this article into
SERVO. I called him Hobbit (
Hobbit has a small servo with an ultrasonic sensor
holder “head” so the robot can look around without having
to turn around.
The Dagu Magician 2WD is quite inexpensive, yet
provides a lot of room for batteries and add-ons.
The assembly manual it comes with is very terse in my
opinion; basically, it’s just a bunch of drawings, but you
should not have any difficulty building the chassis. Frankly,
the biggest problem you will face is exactly where to mount
the Pi because there are a LOT of places you can choose.
However, none of them will fit perfectly centered.
I screw the mounting standoffs into the Pi before trying
to attach it to the top plate of the chassis. This way, you
can see where the male end of the standoffs will fit into
By searching for the right spot, it is possible to mount
the Pi centered in either orientation, but don’t be surprised
if you mount it on the wrong side at first!
A Raspberry Pi Model B or B+ costs less than a Pi
Model 2, but can still use the inexpensive Pi camera in the
future, and it has more USB ports than a Model A. If you
want to use a Pi Model 2, feel free to go ahead. The only
real difference it will make is slightly more power
consumption and faster computation. It will also cost a bit
I used a Pi Model B as it is powerful enough for most
robots, and I had some spare ones at hand.
Easy Wi-Fi is one of the greatest advantages of Pi based
robots. With Wi-Fi, you can:
• Drive your robot from an app or web page like an RC
Dagu Magician 2WD chassis kit.
Raspberry Pi Model B and Model B+.
Wi-Fi adapter plugged into Raspberry Pi Model B+.