Week 3 Notes

January 20th Lab Notes

First try- LED came on with button, would not turn off

• resaved and uploaded code, no change
• did noting, waited and tried button again and it worked
  • guess - loose wiring connection that was fixed accidentally

Off button stopped working again

• seems to only work after waiting a few seconds after turning on.

Took out wiring connected to off button and rewired it

• now works, seems like the tension on the wire was causing it to pop out

January 23rd Class Notes

wiring in series - putting components in a single, unbroken chain

• = 11k resistance

wiring in parallel - putting compontents in two chains that connect into one chain on either end

• = a bit more than 1k resistance

Short Circut - when comething is connecting the positive and negative battery terminal. causes current to rush out and voltage to drop

delay in programming prevents other inputs from being read

pin 13 - onboard LED
pin 1 - tx
pin 0 - rx
pins with ~ - PWM

Coding

Storing Data

letters translate to numbers in ASCII

bit - 1/0, binary-base 2

Conversions:

• 4 bits = 1 nibble
• 8 bits = 1 byte
• 16 bits = 1 word
• 32 bits = 1 long
• 64 bits = 1 double long

byte’s data range is 0 - 255

data is stored in a variable

data types:

8-bit:

• bool - boolean data, true or false
• byte - unsigned (not positive or negative), range 0-255
• char - signed (has positive or negative), range -127-127

16-bit:

• word - unsigned, range 0-65k
• int - intager, signed, range -32k-32k

32-bit:

• unsigned long -good for storing time, range 0-4m
• float - contains decimals, arduinos cannot understand

chip can do addition, subtraction and multiplication

• division must be done in software

in code variables - type name value(optional, default 0)

• example: byte sensorVal = 0;

void - function that does not return anything

Variable Scope

global scope - variable outside of a function, can be used in any function
local scope - variable within a function, can only be used within the function it is defined in

boolean expression:

• either true or fales
• used in if then else statements
• can be multiple expressions
• && is and, both expressions must be true, otherwise whole statement is false

• is or, either expression can be true to make statement true, both must be false or statement is true

conditional statement - if statement, uses boolean expressions

variables must be defined before they are used
functions must be defined before they are used
add const in front of variable, makes variable never changing

Blink without Delay

check to see if 1 second has passed since last blink

• if true, blink again
  • make note of new last blink

unsinged long previousTimeStamp = 0;

int ledState = LOW;

long interval = 1000;

void loop() {

unsigned long currentTimeStamp = millis();

if (currentTimeStamp - previousTimeStamp >= interval) {
    if (ledstate == LOW) {
        ledstate = HIGH;
    } else {
        ledstate = LOW;
    }
    previousTimeStamp = currentTimeStamp;
}
digitalWrite(LED_BUILTIN,ledstate); }

January 25th Class Notes

Serial Communication:

• syncronous - I2C, SPI, 1-Wire
• asyncronous - RS232

serial monitor - shows data coming from micro controller

ReacTable

sparkfun/adafruit - sensors
pololu/hobby town usa - motors/robotics
FFT - Fast Fourier Transform, filters out certain frequencies
Load Cell - determines weight, needs an amplifier

Soldering

Circut Board Components

• Surface Mount - SMD, solders to the top of the board
• Through Hole - TH/PTH, legs poke through board and are soldered to the bottom
• Traces/Tracks - copper on plate connecting components
  • engrave or etch away copper to create tracks
• solder mask - only allows solder to connect to copper
• pad - where copper tracks end, where components are soldered
• plated hole - copper lined holes for PTH compontents, connect top and bottom pads
• refdes - reference designator
• types of boards
  • FR1 - paper based boards, what we use
  • FR2 - fiberglass based boards
• silk screen - white markings on board labeling areas
• via - plated hole from top to bottom

boards are layered - copper / paper or fiberglass / copper

• copper layers are extremely thin

pot - potentiometer

Soldering process

each solder has a specific heating curve
thickness of wires are measured in guage

• the smaller the number, the thinner the wire

Solid vs Stranded wire

• solid stays bent, while stranded will unbend
• solid will bend to break, stranded can be bent and unbent
• solid is a single wire, stranded is individual twisted wires
• solid can withstand higher current than same guage stranded

tinning - coating stranded wire in solder to allow for use in breadboard

Temps:

• 325c for soldering smaller components
• 350c for soldering wires and larger components

we use leaded solder, make sure to be careful of fumes
put a blob of solder on the tip of the wand to help transfer heat
put heat shrink tubing on wire before soldering wires together

• make sure it is far enough away that the heat of the wand does not shrink the tubing