1. Microcontrollers
A microcontroller is a small computer which interacts with its environment, e.g switches, sensors, lights, motors......
It does not have its own operating system
There is no keyboard, mouse, sound, video or internet connection
It's program needs to be stored in an EPROM
Once programmed it simply needs power to operate
A low clock speed is common. This uses less power.

2. In PIC you choose your chip
Factors to consider
Clock frequency
Size of program memory
Erasable memory or not
Number of digital IN and OUT pins
Is analogue to digital included
Cost

3. Introduction to the Arduino
Comparison with the PIC microcontroller
The Arduino is a hobby-type prototyping microcontroller
It can take power from a USB socket or a battery or other source
It uses an Open Source language called “Processing” akin to C++
It uses the PC as its programmer
problema arduo = difficult problem; ino = small so arduino means no problem (my interpretation)

4. Introduction to the Arduino
Comparison with the RPi
The Arduino is a similar size and runs off 5V to 9V
It can handle analogue signals as well as digital
Many freely downloadable projects, both software and hardware (Open Source Hardware)
A community of people well versed in prototyping
Working projects may be purchased and fitted as a “shield”

5. Cost The Arduino Uno alone costs £17
Look in Maplins to see some of the shields which are available
PIC stuff is available there too

6. Lamp example. What the program does.
Fetches information from a web site
From this it calculates a colour in hexadecimal and displays it
Splits the hexadecimal into three to send intensity values to the 3 LEDs
Displays the intensity of the light from the Arduino

7. Lamp example. What the Arduino board does.
A momentarily ON switch, latches the three LEDs either permanently ON or OFF
Adjusts their individual brightnesses according to information received from the program
A photo diode measures light intensity and sends this to the program