PROJECT: Press The Button (PTB2)

OBJECTIVE

Buttons and multi-colored LEDs, oh my!

PROCESS

Do note, the productive way to go about this project involves taking the following steps:

starting early
reading the project page
asking questions regarding things you do not know, are not clear on, or are confused about
as information, concepts, processes become clear, that is something you can contribute to the project documentation (so you can better remember)

If you start too late, and do not ask questions, and do not have enough time and don't know what is going on, you are not doing the project correctly.

TASK

Taking our knowledge of LEDs and buttons:

wire up the multicolored LED (3 separate wiringPi GPIO pins)
- we are going to use software PWM to control this, which will give us 100 levels of adjustment
wire up 3 buttons to individual wiringPi GPIOs (one for red, one for green, one for blue)
wire up the rocker switch to its own wiringPi GPIO
- one direction will indicate positive
- the other direction will indicate negative
implement logic so that, with the rocker switch in a given position, when pressing one of the color buttons, it adjusts that component of the multicolor LED in the appropriate direction (by a step of 10).
- if a color value exceeds or dips below the allowed range, cycle it to the opposite end

GRABIT

To assist with consistency across all implementations, data files for use with this project are available on lab46 via the grabit tool. Be sure to obtain it and ensure your implementation properly works with the provided data.

lab46:~/src/SEMESTER/DESIG$ grabit DESIG PROJECT

EDIT

You will want to go here to edit and fill in the various sections of the document:

https://lab46.g7n.org/notes/c4eng/fall2023/projects/ptb2

PTB2

switch

The switch used has three connection pins:

Connect the central pin to 3.3V, using a 10 KΩ resistor in series
Connect one of the outer pins to a GPIO pin, using a 10 KΩ resistor in series. This pin serves as the ground

button

Your button(s) should produce an input for the RED, GREEN, and BLUE LEDs. All the buttons should be set to input mode since they're input devices. With that information, I would code the button to the corresponding LED. So Red button to the red LED, blue to blue, and green to green. The switch also should be set to input, just like the buttons are. Each button must also be connected to a 3.3v pin. There are 2 on the t-cobbler, I would recommend dividing your wires between the 2 and not just using one.

multicolor LED

[ptb2] The multicolor LED should output the colors RED, GREEN, and BLUE. With that information , I would personally color code the buttons associated with the specific color desired when the button is pressed. Meaning have a RED button cap for when you want the multicolor LED to output RED, and so on for each color. This just makes it easier to test your code. The circuit of the multicolor LED should have a 3.3 V running through the longest leg of the LED. Then there will be a 220k ohm resistor for each of the other legs that are wired to three different gpio pins. The gpio pins serve as a ground, so a separate ground wire is not needed.

if-else

The if else statement essentially means that “ if this condition is true do the following thing, else do this thing instead”. If the condition inside the parentheses evaluates to true , the code inside the if block will execute.

An easy way to write an if statement that executes when our button is pressed, is just to simply combine functions:

if(digitalRead(BUTTON)){
   //some code here//
}

With this method, there is no need to write out a full expression. You can simply evaluate within the if statement.

staying within a range

In this project, we want to stay within a range from 0 to 100, and cycle to the other end of the range when exceeded. One way to do this is to use the modulus operator to take the remainder of our expression divided by our upper range + one factor, i.e.

(10*direction)%110; // 110, since we're jumping by 10s.

Another way to do this would be to add an if statement each time the variable is changed, i.e.

value = 110; 
if(value>100)
   value = 0;

Because there's only one statement being executed after the if statement, there is no need to add curly brackets.

Using this method, we can also make sure we stay in the positives with an additional if statement:

if(value>100)
   value = 0; 
if(value<0)
   value = 100;

Now when we go below 0 or above 100, we will cycle to the other side of the range. It is important to add these if statements directly after the value is changed, to ensure the out-of-bounds value doesn't get used in any code executions.

STRATEGY

The general flow of the process (one way of going about it, anyway) can be described as follows:

SET REDVAL, GRNVAL, BLUVAL TO ZERO
REPEAT INFINITELY:
    SHOULD THE INCREMENT POSITION ON THE SWITCH BE SET:
        SET DIRECTION TO POSITIVE ONE
    OTHERWISE:
        SET DIRECTION TO NEGATIVE ONE

    SHOULD THE RED BUTTON BE PRESSED:
        ADJUST REDVAL BY (TEN TIMES DIRECTION)

    SHOULD THE GREEN BUTTON BE PRESSED:
        ADJUST GRNVAL BY (TEN TIMES DIRECTION)

    SHOULD THE BLUE BUTTON BE PRESSED:
        ADJUST BLUVAL BY (TEN TIMES DIRECTION)

    ACTIVATE MULTICOLOR LED TO RGB VALUES CURRENTLY SET
    
    DELAY AT LEAST FIFTY MILLISECONDS

COMMENT: INFINITE REPEAT BLOCK CONCLUDES

SUBMISSION

To be successful in this project, the following criteria (or their equivalent) must be met:

Project must be submit on time, by the deadline.
- Late submissions will lose 33% credit per day, with the submission window closing on the 3rd day following the deadline.
All code must compile cleanly (no warnings or errors)
- Compile with the -Wall and –std=gnu18 compiler flags
- all requested functionality must conform to stated requirements (either on this document or in a comment banner in source code files themselves).
Executed programs must display in a manner similar to provided output
- output formatted, where applicable, must match that of project requirements
Processing must be correct based on input given and output requested
Output, if applicable, must be correct based on values input
Code must be nicely and consistently indented
Code must be consistently written, to strive for readability from having a consistent style throughout
Code must be commented
- Any “to be implemented” comments MUST be removed
  - these “to be implemented” comments, if still present at evaluation time, will result in points being deducted.
  - Sufficient comments explaining the point of provided logic MUST be present
No global variables (without instructor approval), no goto statements, no calling of main()!
Track/version the source code in your lab46 semester repository
Submit a copy of your source code to me using the submit tool (make submit on lab46 will do this) by the deadline.

Submit Tool Usage

Let's say you have completed work on the project, and are ready to submit, you would do the following (assuming you have a program called uom0.c):

lab46:~/src/SEMESTER/DESIG/PROJECT$ make submit

You should get some sort of confirmation indicating successful submission if all went according to plan. If not, check for typos and or locational mismatches.

RUBRIC

I'll be evaluating the project based on the following criteria:

65:ptb2:final tally of results (65/65)
*:ptb2:used grabit to obtain project by the Sunday prior to duedate [6/6]
*:ptb2:clean compile, no compiler messages [7/7]
*:ptb2:switch is read and adjusts color level direction [13/13]
*:ptb2:each button adjusts its pertinent color level [13/13]
*:ptb2:multicolor LED displays current set RGB levels [13/13]
*:ptb2:code tracked in lab46 semester repo [13/13]

Pertaining to the collaborative authoring of project documentation

each class member is to participate in the contribution of relevant information and formatting of the documentation
- minimal member contributions consist of:
  - near the class average edits (a value of at least four productive edits)
  - near the average class content change average (a value of at least 256 bytes (absolute value of data content change))
  - near the class content contribution average (a value of at least 1kiB)
  - no adding in one commit then later removing in its entirety for the sake of satisfying edit requirements
- adding and formatting data in an organized fashion, aiming to create an informative and readable document that anyone in the class can reference
- content contributions will be factored into a documentation coefficient, a value multiplied against your actual project submission to influence the end result:
  - no contributions, co-efficient is 0.50
  - less than minimum contributions is 0.75
  - met minimum contribution threshold is 1.00

Additionally

Solutions not abiding by spirit of project will be subject to a 50% overall deduction
Solutions not utilizing descriptive why and how comments will be subject to a 25% overall deduction
Solutions not utilizing indentation to promote scope and clarity or otherwise maintaining consistency in code style and presentation will be subject to a 25% overall deduction
Solutions not organized and easy to read (assume a terminal at least 90 characters wide, 40 characters tall) are subject to a 25% overall deduction

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