BigT2 Robot
A robot you can drive with your phone
Why Build the BIGT2 Robot?
It's Fun to Build and Exciting to Use!
Drive with your phone
A magnet for kids
Get kids excited about robotics by connecting the things that they know and value (phones, toys and computer games) and give them something they value learning! The robot uses Bluetooth to connect to your phone, allowing you to drive it like an RC car, only better: you can add custom pre-programmed moves!
Cheap components
Accessible price
Built from low cost generic components from e-Bay, the total cost of the basic robot (without sensors) is about $45.
Simple design
Learning by building
The components and layout of the BigT2 bot where chosen to so that kids could understand what each part of the robot does and how it works. We have converted highly technical complex tasks into simpler diagrams and procedures that help kids learn about electronics and computers.
Programmable in Scratch*
Accessible programming
Based on the standard Arduino Nano chip, the TKC bot can be programmed in Snap4Arduino (a rewrite of Scratch with several improvements). Snap4Arduino is instantly recognised by kids who have used Scratch. Scratch is one of the most widely used graphical languages used to teach programming ideas to primary students.
Build
Have fun!
What the wires do and where they go
This diagram helps you understand what each of the wires does. Use the colour key at the left side to identify the function of each wire.
Put screws in motor controller
The motor controller is the digital clutch of the robot. It stops and starts the motors on command of the 'brains' of the robot.
Get two 15mm screws, two 10 mm screws, and four nylon nuts.
Mount the bigger screws on the bigger part of the motor controller
Mount the caster wheel
Get four 10 mm screws and 4 nuts.
If you use the longer screws the wheel will not spin freely.
Check orientation of chassis
Make sure the hole for the battery switch is on the correct side when you have the robot up-side down.
Mount the motor mounts
Get four 15 mm screws
Be careful not to cross-thread the screws
Do not fully tighten the screws yet: wait until after you tighten the motor screws.
Don't tighten the screws yet
Put the motors on, then tighten the motor mount screws. Otherwise it might be difficult to get the lower bolt on.
If you are buying your own parts be very careful not to cross-thread the screws. If you fully tighten one screw before starting the second screw it magnifies any misalignment, making it very likely you will cross-thread them.
Mount the motors
Get four 25 mm screws, 4 metal nuts and four nylon nuts (as lock washers).
Make sure your motors are oriented correctly: motors outside the pylons, square end towards the square end of the robot.
Mount the motor controller
Push the screws into the four holes in the chassis.
Make sure the black metal heat sink is closer to the narrow end of the robot.
Flip the robot over and put nuts on the two 15 mm screws.
Prepare the battery holders
Turn the switches to on (because they will be hidden under the chassis).
Peel off the backing from the double-sided foam tape
Mount the battery holders
Mount the battery cases on the underside of the robot.
Make sure the switch is in the middle of the hole and battery cases are far enough apart to slide open.
Thread the battery wires up through the chassis.Thread the motor wires through the chassis
Get four 25 mm screws, 4 metal nuts and four nylon nuts (as lock washers).
Connect the motor wires to the motor controller
Push the ends of the motor wires into the sides of the screw terminals, then tighten the screws to hold the wires in place.
Do not unscrew the terminals too far or they will permanently jam open. Instead partial unscrew them and then pry them open with a tiny flat head screwdriver.
Make sure the red wires is closer to the pointy end of the robot.
Mount the voltage regulator
Get two 10 mm screws and two nylon nuts (to act as spacers).
Press the voltage regulator into the holes on the chassis.
Mount the roll bars
Get four 10 mm screws, 4 black nylon spacers and four white nylon spacers
Note the orientation of the hole for the battery switch.
Connect the power wires
Push the red and black wires from the batteries and the voltage regulator into the sides of the screw terminals and then tighten the screws to hold the wires in place.
Mount the computer and wiring board
Push the Arduino computer into the breadboard so that pin 10 is in row 8.
Peel the sticky tape off the back of the breadboard and mount it on the chassis.
Make sure the blue lines are in front of the red lines.
An explanation of how breadboards work.
The metal bars connect adjacent holes/pins
Each of the holes in the two outer columns is tied together.
In each row, five pins on the left are tied together, but they are separate from the five pins on the right hand side of the row.
Add the small wires
The push the wires into the breadboard.
Position is very important! See printed diagram.
Ignore the green wires for now. We will put the green wire into bottom row 10 when we want to boot the robot into program mode (Snap4Arduino).
Add your Bluetooth chip
The HC-05 Bluetooth chip allows yoru robot to talk with your phone or your computer.
Insert the chip so that the antenna and the circular button are facing the yellow and white wires.
Unmodified HC-05 chips can talk to your Android phone, but not to SNAP. Chips labelled something like 'SNAPbot-103' have been reprogrammed to work at the faster speed that SNAP requires.
iOS compatible chips (HM-10) have four pins and no button.
Connect Arduino to motor controller
Plug a four-wire bundle into the holes next to Arduino pins 2,3,4 &5 then into the four pins closest to the edge of the motor controller. These pins are labelled IN!, IN2, IN3 & IN4.
Do not use the internal pins labelled 5v, GND, GND and 5v.
Profile
Bob Elliott
Robotics enthusiast
Bob is a maths/science/robotics teacher who supports the DoE Gifted Online Smartbots program. He has been a member of the Robotics Tamania committee for several years, helping to run the Tasmanian state finals of Robocup Jr. He runs several robotics clubs and runs Arduino robot workshops in school workshops in collaboration with Stuart Thorn of the Bigger Things project and holiday workshops at Enterprize and the Kingston and Bridgwater LINCs.
