February, 2013

In preparation for the 2nd annual Robot Club for my kid’s elementary school, I created LineBot.  I wanted a robot that the kids could build from scratch (with no soldering), but less complicated than last year.  I also wanted to keep the price low to make it affordable for the students.  With bulk discounts and aggressive part shopping, I was able to get the price to $125 per student.  It’s an increase from last year, but this robot is a bit more complex than last year.  As with last year, each kid will build their own robot (no sharing), and they will take it home with them at the end.

LineBot leverages an Arduino Uno which helps to decrease the complexity.  I also used an Ardumoto shield for motor control (I’ll pre-solder the headers and screw terms).  Using these will help accelerate the build since it means fewer parts on the breadboard and easy programming.  LineBot also uses the Magician’s Chassis from Sparkfun.  This is a great kit and is very inexpensive.  Unfortunately the hex standoffs are not tall enough to let me change the batteries, so I replaced them with larger ones.  I also added 3 hex standoffs in the front as eye stalks to hold the line sensors.  Also, the motors are not very powerful, but they are good enough for the needs of this robot since I have effectively managed the weight.  For the line sensors, I’m using Sparkfun’s analog line sensors – low cost, but not very durable – I’ve had to re-solder a few of them.  Finally, I’ve mounted a solderless breadboard to house a buzzer and 3 LEDs as indicators for the line sensor status.

Like last year, I’ll have the kids focus on 3 phases of the build:  Mechanical, Electrical, and Software.  We’ll meet every other week for 5 classes, 2 hours each.

  • Meeting 1:  Introduction to Arduino
  • Meeting 2:  Mechanical Build (assemble the chassis)
  • Meeting 3:  Electrical Build (cut wires, place components onto the breadboard)
  • Meeting 4:  Software Build (write the pseudocode, type in the source code, upload to the robot)
  • Meeting 5:  Decorate

Feedback from last year’s class was that they really enjoyed using the wire cutter/stripper during the electrical build, and they really enjoyed decorating their robot after the build was complete.  I will incorporate both of those aspects into this year’s build.  I’ll give each kid a 22″ x 28″ poster board with black electrical tape to let them test the robot.

This year, like last year, I’ll open the class to 15 students.  My son and wife have volunteered to help.

Arduino Uno Source Code


DSCN0135 DSCN0137

Parts List:

LineBot Parts List

Arduino Pins

0 Rx
1 Tx
3 Speed Motor A (PWM)
5 Left Line LED
6 Center Line LED
7 Rigth Line LED
9 Buzzer (PWM)
11 Speed Motor B (PWM)
12 Motor Direction Motor A
13 Motor Direction Motor B
0 Left Line Sensor
1 Center Line Sensor
2 Right Line Sensor

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