Pololu Zumo Shield User manual

Pololu Zumo Shield for Arduino
User's Guide
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.a. Contacting Pololu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.b. Included components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.a. What you will need . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.b. Assembling the Zumo Shield and chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.c. Adding a Zumo reflectance sensor array (optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3. The Zumo Shield in detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.a. Features and components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.b. Front expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.c. Jumper settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.d. 3-axis compass module (accelerometer and magnetometer) . . . . . . . . . . . . . . . . . . . . . . . . 26
4. Schematic diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5. Arduino pin assignment table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6. Zumo Shield Arduino Libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7. Example projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.a. RC Zumo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.b. Simple border-detecting sumo robot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
7.c. Maze solver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
7.d. Using the compass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8. Controlling a servo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
8.a. Controlling a servo with an Arduino Uno . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
8.b. Controlling a servo with an Arduino Leonardo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Pololu Zumo Shield for Arduino User's Guide © 2001–2013 Pololu Corporation
http://www.pololu.com/docs/0J57/all Page 1 of 38

1. Overview
The Zumo Shield provides a convenient interface between our Zumo chassis [http://www.pololu.com/catalog/product/1418]
and an Arduino Uno [http://www.pololu.com/catalog/product/2191] or Leonardo [http://www.pololu.com/catalog/product/2192] (it
is not compatible with the Arduino Mega or Due, but it can be used with older Arduinos that have the same form
factor as the Uno, such as the Duemilanove). The shield mounts directly to the chassis, connecting to its battery
terminals and motors, and the Arduino plugs into the shield’s male header pins, face down. The shield provides all the
electronics necessary to power the motors and includes some additional fun components for making a more interesting
robot, such as a buzzer for making sounds and a 3-axis accelerometer and compass.
Zumo Shield for Arduino. Assembled Zumo robot with a Zumo
Shield, Arduino Uno, and Zumo blade.
A Zumo chassis, Zumo Shield, and Arduino can be combined to become a low-profile, Arduino-controlled tracked
robot that is less than 10 cm on each side (small enough to qualify for Mini-Sumo competitions).
Zumo Shield for Arduino, labeled top
view.
Zumo robot assembled with a Zumo
Shield and Arduino Uno, back view.
The Zumo Shield is available:
•by itself [http://www.pololu.com/catalog/product/2504];
• as part of a Zumo robot kit for Arduino [http://www.pololu.com/catalog/product/2505] that also includes a Zumo
chassis [http://www.pololu.com/catalog/product/1418] and a stainless steel Zumo blade [http://www.pololu.com/catalog/
product/1410]; or
• as a fully-assembled Zumo robot for Arduino [http://www.pololu.com/catalog/product/2506] with 75:1 HP motors
[http://www.pololu.com/catalog/product/2361] and a reflectance sensor array [http://www.pololu.com/catalog/product/1419]
installed.
Pololu Zumo Shield for Arduino User's Guide © 2001–2013 Pololu Corporation
1. Overview Page 2 of 38

Fully assembled Zumo chassis
with assembled Zumo Shield.
1.a. Contacting Pololu
We would be delighted to hear from you about your experiences with the
Zumo Shield for Arduino [http://www.pololu.com/catalog/product/2504],Zumo
robot kit for Arduino [http://www.pololu.com/catalog/product/2505], or Zumo
robot for Arduino [http://www.pololu.com/catalog/product/2506]. If you need
technical support or have any feedback you would like to share, you can
contact us [http://www.pololu.com/contact] directly or post on our forum
[http://forum.pololu.com/viewforum.php?f=29]. Tell us what we did well, what we
could improve, what you would like to see in the future, or anything else you
would like to say!
1.b. Included components
The Zumo Shield is available:
•by itself [http://www.pololu.com/catalog/product/2504];
• as part of a Zumo robot kit for Arduino [http://www.pololu.com/catalog/product/2505] that also includes a Zumo
chassis [http://www.pololu.com/catalog/product/1418] and a stainless steel Zumo blade [http://www.pololu.com/catalog/
product/1410]; or
• as a fully-assembled Zumo robot for Arduino [http://www.pololu.com/catalog/product/2506] with 75:1 HP motors
[http://www.pololu.com/catalog/product/2361] and a reflectance sensor array [http://www.pololu.com/catalog/product/1419]
installed.
Zumo Shield
The shield itself comes with the following components:
• right-angle slide switch
• two pushbuttons [http://www.pololu.com/catalog/product/
1400]
• buzzer
•2-pin battery-charging header
[http://www.pololu.com/catalog/product/1012]
• three jumper wires (for soldering motors to the
chassis)
• 40-pin 0.1″ straight breakaway male header
[http://www.pololu.com/catalog/product/965]
• two blue shorting blocks
[http://www.pololu.com/catalog/product/968]
• two 5/16″ #2-56 machine screws (to be used instead of the 1/4″ screws included with the chassis kit if you
attach a Zumo blade)
• 1/16″ black acrylic spacer plate (two pieces)
Zumo Robot Kit for Arduino
In addition to the shield and its included hardware, the Zumo robot kit for Arduino also includes these components:
Pololu Zumo Shield for Arduino User's Guide © 2001–2013 Pololu Corporation
1. Overview Page 3 of 38

•Zumo chassis kit [http://www.pololu.com/catalog/product/
1418], which includes:
◦ Zumo chassis main body
◦ 1/16″ black acrylic mounting plate (not used with
the Zumo Shield)
◦ Two drive sprockets
◦ Two idler sprockets
◦ Two 22-tooth silicone tracks
◦ Two shoulder bolts with washers and M3 nuts
◦ Four 1/4″ #2-56 screws and nuts
◦ Battery terminals
•Basic sumo blade for Zumo chassis
[http://www.pololu.com/catalog/product/1410]
You will receive the black acrylic spacer and mounting plates with protective paper masking on both
sides. You can peel this masking off to expose the acrylic surface, or you can leave it on to increase
the thickness of the plates.
The shield and chassis kit include extra parts like jumper wires, screws, nuts, and washers, so do not
be concerned if you have some leftover hardware after assembling your Zumo.
Zumo Robot for Arduino
The Zumo robot for Arduino is a fully-assembled robot
platform built from the same components found in the
Zumo robot kit for Arduino, along with these additions:
• Two 75:1 HP micro metal gearmotors
[http://www.pololu.com/catalog/product/2361]
•Zumo reflectance sensor array
[http://www.pololu.com/catalog/product/1419]
Pololu Zumo Shield for Arduino User's Guide © 2001–2013 Pololu Corporation
1. Overview Page 4 of 38

2. Assembly
If you have a Zumo robot kit for Arduino [http://www.pololu.com/catalog/product/2505] or a separate Zumo Shield
[http://www.pololu.com/catalog/product/2504] and chassis [http://www.pololu.com/catalog/product/1418], this section will guide
you through assembling them into a complete robot.
If you purchased an assembled Zumo robot for Arduino [http://www.pololu.com/catalog/product/2506], this assembly work
has been done for you, although you might want to configure your Zumo by adding or removing some jumper
connections [http://www.pololu.com/docs/0J57/3.c]. Otherwise, you can simply install four AA batteries and an Arduino
(or compatible controller) and skip to Section 3 to start learning how to use your Zumo!
2.a. What you will need
The Zumo Shield is designed to be mounted on a Zumo chassis kit [http://www.pololu.com/catalog/product/1418], which
is included (along with a Zumo blade [http://www.pololu.com/catalog/product/1410]) if you have a Zumo robot kit for
Arduino [http://www.pololu.com/catalog/product/2505]. In addition, you will require these items to construct a working
Arduino-controlled Zumo robot:
Additional required components
• Two micro metal gearmotors [http://www.pololu.com/catalog/category/60] (we recommend 100:1
[http://www.pololu.com/catalog/product/1101],75:1 [http://www.pololu.com/catalog/product/2361], or 50:1
[http://www.pololu.com/catalog/product/998] gear ratio versions with HP motors). The pre-assembled version of the
Zumo robot [http://www.pololu.com/catalog/product/2506] includes two 75:1 HP micro metal gearmotors.
• An Arduino (we recommend an Uno R3 [http://www.pololu.com/catalog/product/2191] or a Leonardo
[http://www.pololu.com/catalog/product/2192])
• Four AA batteries (we recommend rechargeable AA NiMH cells [http://www.pololu.com/catalog/product/1003])
Please see the product description for the chassis kit [http://www.pololu.com/catalog/product/1418] for more information
and recommendations about selecting these components.
Additional optional components
•Zumo reflectance sensor array [http://www.pololu.com/catalog/product/1419]
•Basic sumo blade for the Zumo chassis [http://www.pololu.com/catalog/product/1410]
•Sensors [http://www.pololu.com/catalog/category/7], such as our QTR reflectance sensors
[http://www.pololu.com/catalog/category/123]
•Connectors and jumper wires [http://www.pololu.com/catalog/category/19], for connecting additional sensors and
components
• Battery charger (such as the iMAX-B6AC [http://www.pololu.com/catalog/product/2260]), if you are using
rechargeable batteries
Assembly tools
• Soldering iron and solder (we recommend one with adjustable temperature control)
• Wire cutter
• Small Phillips screwdriver
• 3 mm Allen wrench (hex key)
• long-nose pliers (for bending the Zumo blade mounting tabs)
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2. Assembly Page 5 of 38

2.b. Assembling the Zumo Shield and chassis
Please follow these instructions carefully to assemble your Zumo Shield and chassis properly.
Through-hole parts
1. Solder the included through-hole
components to the shield:
◦ power switch
◦ reset pushbutton
◦ user pushbutton
◦ buzzer
◦ charging connector (1×2-pin
female header)
2. On the bottom of the board, trim
any leads longer than 1/16″ (the
thickness of the spacer plate) so they
do not prevent the shield from sitting
flat on the spacer plate and chassis.
Arduino headers
3. Separate the 1×40-pin
breakaway male header into the
appropriate segments for connecting
your Arduino and solder them to the
shield. These header segments
should be soldered to the sets of
holes outlined with white rectangles
on the top of the shield, with the pins
facing up.
The newest Arduino boards, including the Uno R3 and the Leonardo, use one 1×10 header, two 1×8 headers, and one
1×6 header; older Arduino boards use two 1×8 headers and two 1×6 headers (the two pairs of pins highlighted above
in red should not be populated if you are using this board with an older Arduino that does not support these additional
pins). Please make sure you solder the appropriate headers for your particular Arduino!
An easy way to line up the Arduino headers for soldering is to plug them into an Arduino, then place the shield upside-
down on top of them, as shown in the picture below. Be careful to insert the header pins into the correct set of holes
before you begin soldering. Note: if you use this alignment technique, make sure your soldering iron temperature is
not excessively hot and avoid holding the iron on a single pin for more than a few seconds as this could melt the
Arduino’s female headers.
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2. Assembly Page 6 of 38

4. On the bottom of the board, trim the four Arduino header pins closest to the front of the board on each side
to prevent them from contacting the motor housings. If you think there is a chance these pins might still touch
the motor cases, you can put some electrical tape on the motors to act as insulation.
Jumpers and additional connections
5. Optional: If you want to enable the buzzer, enable the battery level input, or disable the compass, now is
a good time to add and/or cut jumper connections to configure the shield to your liking. This can also be done
later, though soldering to these pins is more difficult once the robot is assembled (especially if you decide later
you want to add header pins for use with shorting blocks; this would require a lot of disassembly). The jumpers
are explained in detail in Section 3.c. The buzzer and battery level jumpers can be connected by soldering in a
short piece of wire between the two holes, while the compass I²C connections can be broken by cutting the trace
on the top of the board between the holes. Note: there is not enough clearance to use male headers on the battery
level and compass I²C jumpers if you are using an Arduino with a DIP (through-hole) microcontroller.
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2. Assembly Page 7 of 38

Instead of making a wire connection, you can solder a 1×3 male header to the buzzer jumper holes to
allow the use of a shorting block for connecting the buzzer. You can also use male headers and shorting
blocks for the battery level jumper and compass jumpers if you have an Arduino Leonardo or an
Arduino Uno with an SMD (surface mount) microcontroller. However, there is not enough clearance
to use male headers on the battery level and compass I²C jumpers if you are using an Arduino with a
DIP (through-hole) microcontroller.
6. Optional: At this point, you might consider soldering additional components (such as sensors), or headers
or wires for connecting them, to the shield. If you do this, please check to make sure your part placement
does not interfere with the shield’s ability to mate with the Arduino or the chassis. In particular, note that only
components in the outermost three rows of the front expansion area can extend below the board (the fourth front-
expansion row can only be used for pins extending above the board), and if you add any through-hole parts to
the prototyping areas on the shield, you will need to drill corresponding holes in the acrylic spacer plate for the
leads to fit into.
Motors
7. Cut two of the included jumper wires in half to form four segments, and trim off the ends that are covered
in adhesive (the adhesive could interfere with making a good electrical connection to the motor). These wire
segments will be used as motor leads.
8. Solder a pair of leads to each motor. You might find it helpful to make a small bend at the tip of each lead
to hook into the hole in the motor lead tab to hold it in place for soldering. Warning: holding the soldering iron
against the motor lead for more than a few seconds can start to damage the motor brushes, so try to be reasonably
Pololu Zumo Shield for Arduino User's Guide © 2001–2013 Pololu Corporation
2. Assembly Page 8 of 38

quick/efficient with this soldering; if the first attempt does not go well, remove the soldering iron and let the
motor cool for a few seconds before trying again.
Each motor’s positive terminal is indicated by a plus sign (+) in the black plastic end of the motor, visible at the
bottom of the picture above. The motors should be soldered into the shield with the positive terminal closest to
the front, so you should attach the leads to allow the motors to be oriented this way. (However, don’t worry if you
accidentally get the orientation of one or both motors wrong. You can later compensate for it in software with our
ZumoMotors library [http://www.pololu.com/docs/0J57/6].)
9. Place the motors into the channel in the front of the chassis, aligning the gearbox with the grooves in the
channel. The front plate of the gearbox should be even with the edge of the chassis.
Pololu Zumo Shield for Arduino User's Guide © 2001–2013 Pololu Corporation
2. Assembly Page 9 of 38

Chassis and shield
To assemble the chassis with the Zumo Shield, you should use the two-piece acrylic spacer plate that
is included with the shield. You will not need the one-piece mounting plate that is included with the
Zumo chassis.
10. Place an M3 nut in each of the two side slots near the rear of the chassis. The slots are sized so that nuts
will not be able to rotate within them. (These nuts will be used to mount the idler sprockets later.)
11. If you want, peel the protective paper masking off both sides of the acrylic spacer plate pieces (the spacer
plates in our pictures show what they will look like with the masking peeled off). Alternatively, you can leave
the masking on for additional thickness. If you leave the masking on, it will be mostly concealed when the robot
is fully assembled.
12. Cover the chassis and motors with the spacer plate pieces and then the Zumo shield. The holes in the spacer
plate should line up with the through-holes in the shield resting on top of it. There is only one correct orientation
for these plates. (The plate consists of two separate pieces to make it possible to disassemble the Zumo without
having to desolder the motors or battery terminals.)
13. In each of the four mounting holes, insert a #2-56 machine screw through the shield, spacer plate, and
chassis, and tighten it against a nut under the chassis. You can line up the nut by feel, or you could try temporarily
taping the nuts inside the recesses in the chassis. Note that the kit includes two different sizes of #2-56 machine
screws: 1/4″and 5/16″. The two longer screws are intended for use in the front holes (near the motors) if you are
also mounting a sumo blade; otherwise, you can use the shorter 1/4″ screws for all four mounting holes.
If you are also adding a basic sumo blade, you can either mount it now or add it later after you are done soldering the
motors and battery contacts. (Note: If you intend to solder anything to the front expansion area of the shield, such as
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