Wednesday, 1 June 2011

First Attempt

To make my car autonomous I used  the following parts:
  • My RC10B4
This was assembled from a kit and has an electronic speed controller linked to a brushless motor, servo for steering, an old racing battery and a receiver (unused for this autonomous experiment).

The Arduino Uno is a great little microprocessor board that allows you to run c programs to do things. It has 13 digital inputs/outputs and 6 analog inputs. Of the digital outputs 6 of them support pulse width modulation (PWM), which means they can drive servos or electronic speed controllers. The Arduino has a great website with lots of resources. I can already program in c, so I found it very easy to pick up and use. The .:oomlout:. website has a great starter kit (It's where I get my stuff for now, but not the only webstore out there). 
This comes as a kit that needs to be soldered together.
My one has removable power strips to make it more compact.

  • An extra servo (already had this lying around)

This can give distance reading between 10 and 80cm.
  • Lots of blu tack

  • Ice cream box lid

This is how to build my prototype,
  1. Cut the lid to 66x84mm and drilled 6 3mm holes. Two holes are 53mm apart on the short edge as shown above and the other holes match the arduino (use a pen through the holes in the arduino to find where to drill them).
  2. Attach the arduino to the ice cream box lid using plastic screws and nuts. The locations of the screws are important, also make sure you attach a nut between the arduino and the lid to keep it off the lid.

     3.  Plug the protoshield to the arduino.

     4.  Place the breadboard with no power rails on top of the protoboard.

     5.  Unscrew these screws (9643 from step 5 on page 9 of the car manual).

     6.  Screw the lid onto the car using the screw that where just removed. Make sure you have a charged battery already in the car, otherwise you have to take it all apart to get a battery in or out.

     7.  Blu tack the infra red sensor onto the servo horn and blu tack the servo onto the car. Make sure it doesn't interfere with the steering servo.

    8.  Connect the electronic speed control servo lead to the 5V (red), GND (black) and arduino digital pin 3 (white). Connect the steering servo lead to the 5V (red), GND (black) and arduino digital pin 9 (yellow). Connect the sweeper servo lead to the 5V (red), GND (black) and arduino digital pin  6 (yellow). Connect the infra red sensor to 5V (red), GND (black) and arduino analog pin 0 (white). I found putting a jumper wire into the same holes in the breadboard as the infra red sensor stopped them from coming out. There are 5 headers for 5V and GND on the protoshield to make it easier. Digital pins 3, 6 and 9 are used because they all support pulse width modulation.

So that is what I built as my prototype. Next post will be the videos of it working and the program uploaded to the arduino.

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