After much deliberation I finally purchased the 4WD Aluminium Mobile Platform from RobotBase.cn and available in the UK from Robot Bits. This 4WD metal base arrives in kit form with motors, a battery holder and switch.
In this experiment I am going to use my first outside library to add Capacitive Sensing to the Arduino as demonstrated on You Tube. This is the same technique used by most modern touch screen such as the iPad and iPhone and this feature is brought to the Arduino via the CapSense library written by Paul Badger.
Shift Registers are a type of Integrated Circuit (IC) or chip. The Shift Register is a serial to parallel convertor that allows us to control eight additional output pins with just three on the Arduino. You can link them together to give you even more (unlimited) outputs!
A Shift Register works by clocking in the data and then locking (or latching) it. This is achieved by setting the data pin to high or low and then pulsing the clock. This is repeated until you have shifted out eight bits of data and set all the pins. Now you can pulse the latch and all eight bits are output to their representative pins.
Servos can be used for lots of things where a great detail of control is needed such as steering RC vehicles, robotics and freaking out small children with moving dolls. Standard Servos like the one provided by Oomlout travel through 0 to 180 degrees with positioning controlled via a timed pulse. Timing varies with manufacturer but for example a pulse sent every 25 to 50 ms will run the servo smoothly.
The Arduino will allow you to attach low power devices directly to its pins but items such as motors requiring more power require a transistor. A Transistor allows you to switch big volts using little volts. In circuit 03 we wil be switching a motor.
It uses a 1N4001 diode to act as a flyback diode which eliminates or suppresses voltage spikes seen across an inductive load when a voltage supply is suddenly reduced or removed.
So in the second starter circuit multiple LEDs are linked up and patterns created. The first one turns each LED on before turning each LED off. It uses an array and a couple of for loops. You can read the full explanation on ardx.org.
This is the first ‘getting started’ circuit that makes an LED blink on and off as per the Ardx explanation. The circuit is nice and simple using just the big LED, a 560 ohm Resisitor (Green-Blue-Brown) and a wire to link the positive leg (long) of the LED to the digital pin 13 on the Arduino.