If you want to build something using a Raspberry Pi, you'll probably use resistors. For this exercise, you need to know two things about them:
- Each resistor has a resistance value.
- Resistors are small - so small in fact that if you printed the resistance value on them, it would be hard to read.
To get around this problem, manufacturers print color-coded bands onto the resistors to denote their resistance values. Each band has a position and a numeric value.
The first 2 bands of a resistor have a simple encoding scheme: each color maps to a single number.
In this exercise you are going to create a helpful program so that you don't have to remember the values of the bands.
These colors are encoded as follows:
- Black: 0
- Brown: 1
- Red: 2
- Orange: 3
- Yellow: 4
- Green: 5
- Blue: 6
- Violet: 7
- Grey: 8
- White: 9
The goal of this exercise is to create a way:
- to look up the numerical value associated with a particular color band
- to list the different band colors
Mnemonics map the colors to the numbers, that, when stored as an array, happen to map to their index in the array: Better Be Right Or Your Great Big Values Go Wrong.
More information on the color encoding of resistors can be found in the Electronic color code Wikipedia article.