micro:bot Kit Experiment Guide

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Contributors: D___Run___, TheDarkSaint
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Assembling Your Robot

This section will cover how to assemble your robot chassis. Assembly time: 30-60 minutes

The robot chassis requires the following pieces to build. You’ll find most of them in your SparkFun micro:bot kit.

Note: Several of the parts need to be snapped out of the main chassis panels.

micro:bot chassis parts

Click on the image for a closer look.

Letter Part Qty
A Bottom Chassis Plate 1
B Top Chassis Plate 1
C Front Motor Mount 2
D Rear Motor Mount 2
E Side Strut 4
F Encoder Mount (Not Used in this Guide) 2
G moto:bit Mount 2
H Battery Pack Clip 1
I Line Follower Mount 1
J Line Follower Mount Plate 1
K Jumper Wire — 3-pin, 6" 3
L Wheels 2
M Nub Caster 1
N DC Motors 2
O Line Follower Boards 3
P 4xAA Battery Holder 1
Q 4xAA Batteries (Not Included) 3
micro:bit Not Included in Kit 1
moto:bit Included in Kit 1

No Tools Necessary

The robot chassis does not require any additional tools.

WARNING: Do not attempt to remove chassis parts by squeezing them with pliers. If you try to muscle it too much you risk breaking them and compromising the structure of your robot. Handle with care. ;)

No Pliers

A Note About Orientation

When we talk about the “front,” “left,” “right,” and “back” of the Shadow Chassis, we are referring to specific sides of the robot when viewed from above.

micro:bot Orientation

Notice that we consider the SparkFun moto:bit to be on the “back” of the bot and the Bumper Whiskers and Line Follower Boards to be in the “front.”

Assembly

Installing Motors

Let’s begin by installing the motors that will control the wheels. Locate the following:

Installing Motors Parts

Attach Rear Motor Mounts

Hold the wires near the middle of the Motor (N), and carefully slide a Rear Motor Mount (D) in from the side and over the two motor wires. Be careful not to snag the wires, the cable tie, or the clear plastic strap.

Attaching Rear Motor Mounts

Holding the motor wires, gently twist the Rear Motor Mount counter clockwise so that it snaps in place on the motor and the wires are centered in the gap of the motor mount. Again, be sure not to snag the wires under the motor mount.

Adjusting Rear Motor Mount

Repeat the process for the second motor, ensuring that it is a mirror image of the first.

Both Rear Motor Mounts

Attach the Front Motor Mounts

Slide a Front Motor Mount (C) onto the protruding eyelet on the front of a Motor (N). Ensure the rounded sides of the motor mounts are facing the same way.

Attaching Front Motor Mounts

Repeat the process for the second motor.

Both Front Motor Mounts

Attach the Motor Assemblies to the Chassis

Snap one of the motor assemblies into the left two horizontal slots of the Bottom Chassis Plate (A). Make sure that the rounded edges of the motor mounts and the wires are facing toward the center of the chassis. Repeat for the opposite motor.

Attaching Motor Assemblies to Chassis

Attach the Wheels

Slide one Wheel (L) onto the plastic shaft of a Motor (N). Look at the motor shaft. Notice it has two flat edges. Make sure to line up the flat edges of the motor shaft with the flat edges of the wheel.

Attaching Wheel

Repeat with the other wheel.

Two Wheels Ready to Roll

Installing the Line Sensors

This section will cover the Line Following Sensors array assembly. You’ll first build the Line Following array and then attach it to the chassis. Locate the following:

Line Sensor Parts

Construct the Line Follower Assembly

Attach the three Line Follower Boards (O) to the Line Follower Mount (I) such that the rectangular pegs in the Line Follower Mount poke through the mounting holes in the Line Follower Boards. Make sure the sensors are facing away/down from the clip of the mount.

Line Follower Boards on Mount

Place the Line Follower Mount Plate (J) on top of the Line Follower Mount (I) so that the center clip of the mount is poking through the center slot of the plate.

Mount Plate on Top of Line Follower Boards

Attach the Cables

You will need to connect a 3-Wire Jumper Cable (K) to each of the Line Follower Boards (O). Note the color of the wire attached to each pin.

Line Follower Connections:

Jumper Wire Color RedBot Sensor - Line Follower
Red GND
Orange VCC
Yellow OUT

Attach all 3 cables to the 3 Line Follower Boards. Notice that the yellow wire should be on the right (out) and the red wire should be on the left (ground).

Attach Cables to Line Follower Boards

Attach the Line Follower Assembly to the Chassis

Locate the wide, rectangular slot near the front of the chassis and snap the line follower assembly in from the bottom side of the chassis. Route the cables through the large hole in the bottom plate.

Attach Line Follower Assembly to Chassis

The bottom of your chassis should look like the following image allowing the line sensors to be facing down.

Line Followers Mounted Bottom View

Final Assembly

With the motors and a few sensors attached, we can assemble the main body of the robot. Locate the following:

Side Strut and Nub Caster Assembly

You will also need the Top Chassis Plate and Bottom Chassis Plate assemblies, which have any additional parts and sensors you attached in previous steps.

Attach the Nub Caster

Snap the Nub Caster (M) into the slot on the back of the Bottom Chassis Plate assembly. Make sure the Nub Caster is on the side opposite the motors (the bottom side).

Attach Nub Caster

Add the Side Struts

Snap the four Side Struts (E) into the diagonal slots on the four corners of the Bottom Chassis Plate assembly.

Attach Side Struts

Pull the cables through the cutouts on the chassis.

Cables through Cutouts

Route the Cables

Position the Top Chassis Plate over the Bottom Chassis Plate – but do not snap the two plates together yet. Make sure that the front sides of each plate line up.

Route the wires and cables through the left and right oval slots in the Top Chassis Plate assembly as shown. For the center line follower sensor, route this cable through the right oval slot. Note that SIK-only cables are listed with an asterisk (*).

NOTE: It might be a good idea to use some pieces of masking tape to mark which cables go to which component. It’s not necessary, but it might help keep things organized.

Cable Routing:

Cable Connection Oval Side
Left Line Follower Center
Center Line Follower Center
Right Line Follower Center
Left Motor wires (red and black) Left
Right Motor wires (red and black) Right

Pull Wires Through and Prepare Top Plate

Attach Top Chassis Plate Assembly

Line up the Top Chassis Plate on top of all the struts, and carefully snap the Top Chassis Plate assembly onto the side struts and motor mounts. Press gently above each side strut individually until they each snap into place. If you have the Bumpers installed, make sure the boards are between the top and bottom plates.

Snap Top Plate On

If you need to remove the plate to change anything, gently pull upward on each side strut individually. Do not attempt to use pliers or hand tools, or you may end up snapping the plastic clip.

Attaching the moto:bit

In this section, you will add brains of the robot: the SparkFun moto:bit. Locate the following:

Attaching moto:bit

You will also need the full chassis assembly, which contains any additional parts and sensors you attached in previous steps.

Attach the moto:bit Mounts

Snap the two moto:bit mounts (G) into the vertical slots in the back of the top chassis plate near the large rectangular opening.

Add Controller Board Mounts

Both of these mounts will enable your moto:bit board to be mounted to the chassis.

Both moto:bit Moutns

Add the moto:bit

Before you snap in the moto:bit board, insert your micro:bit into the moto:bit as shown here.

Inserting micro:bit into moto:bit

The moto:bit snaps into the lowest of the notches on the moto:bit Mounts (G). Make sure the power jack is facing the left side of the robot. Push gently and evenly until it snaps into place.

Snap In Main Board

NOTE:The other slots in the moto:bit mounts can be used to hold the Arduino UNO or the Sparkfun RedBoard.

Connecting the Cables

It is time to connect the jumper wires; it is really important that these connections are right.

Loose Wires

You can follow along with the pin out tables or scroll down for a diagram. Trace each cable poking through the top chassis plate to make sure you know what it is connected to.

Please Note: When you have the micro:bot upright and the front of the chassis facing away from you, "left" sensors/motors will be on the left side and "right" sensors/motors will be on the right side. Also, the motor wires are intentionally switched for the right motor -- see notes below.

micro:bot Annotated

Line Followers


Left Line Follower:

SparkFun moto:bit Pins Jumper Wires Left Line Follower Board
P0 3-Wire Jumper Cable - Yellow OUT
3.3V 3-Wire Jumper Cable - Orange VCC
GND 3-Wire Jumper Cable - Red GND

Center Line Follower:

SparkFun moto:bit Pins Jumper Wires Middle Line Follower Board
P1 3-Wire Jumper Cable - Yellow OUT
3.3V 3-Wire Jumper Cable - Orange VCC
GND 3-Wire Jumper Cable - Red GND

Right Line Follower:

SparkFun moto:bit Pins Jumper Wires Right Line Follower Board
P2 3-Wire Jumper Cable - Yellow OUT
3.3V 3-Wire Jumper Cable - Orange VCC
GND 3-Wire Jumper Cable - Red GND

Line Follower Connection


Motors


Left Motor:

SparkFun moto:bit Pins Left Motor Jumper Wires
LEFT MOTOR - RED Soldered on Motor Jumper Wire - RED
LEFT MOTOR - BLACK Soldered on Motor Jumper Wire - BLACK

Right Motor:

moto:bit Pins Right Motor Jumper Wires
RIGHT MOTOR - RED Soldered on Motor Jumper Wire - BLACK
RIGHT MOTOR - BLACK Soldered on Motor Jumper Wire - RED

Black Wire Motor

Red Wire Motor

Once all wires are connected it should look like the following image.

All Wire Connections Made

Batteries

The last step is to provide a power source for the micro:bot. You will need to provide your own AA batteries (Q). Locate the following:

Batteries and Clip Parts

Insert Batteries

Insert the AA batteries into the Battery Holder (P). Makes sure the batteries are facing the correct direction, as per the markings inside of the Battery Holder.

Insert AA Batteries into Pack

Attach Battery Pack

Insert the Battery Holder (P) with batteries into the back cavity of the chassis. Position the Battery Holder so that the barrel jack cable comes out on the left side of the robot.

Insert Battery Pack

Insert the Battery Pack Clip (H) on top of the battery pack.

Insert Battery Pack Clip

Twist and position the clip so that it rests on top of the battery pack.

Attach Battery Pack Clip

Push the clip down into the vertical slots in the Bottom Chassis Plate so it snaps in place.

Snapping Battery Clip into Chassis

Route the barrel jack cable out of the left side of the chassis and up to the moto:bit.

Route Barrel Jack Cable

Plug the barrel jack cable into the barrel connector on the side of the moto:bit carrier board.

Plug into Barrel Connector

Changing the Batteries

If you find that you need to replace the batteries in the micro:bot, the process is simple. Unplug the battery pack from the moto:bit.

Unplug the Batteries

Turn the micro:bot over and push on the Battery Holder through the hole in the Bottom Chassis Plate. This will cause the Battery Pack Clip to unsnap from the Bottom Chassis Plate.

Push on battery pack to unsnap it

Slide the Battery Pack and Clip out from the back of the micro:bot.

Remove Battery Clip

Remove Battery Pack

Change the batteries, and follow the steps in Attach Battery Pack section above to put the Battery Pack back in the micro:bot.