Asynchronous Serial communication
RX = Receive line
TX = Transmit line
Laptop - Arduino
RX -> TX
TX <- RX
This is how the computer communicate with Arduino.
asynchronous serial communication
Communicating serially involves sending a series of digital pulses back and forth between devices at a mutually agreed-upon rate.
In order to communicate, the two devices need to agree on a few things:
- the rate at which data is sent and read
- the voltage levels representing a 1 or a 0 bit
- the meaning of those voltage levels; is a high voltage 1 and a low voltage 0, or is the signal inverted so that a low voltage is a 1 and high voltage is 0?
you’d make three connections between the two devices:
- a common ground connection, so both devices have a common reference by which to measure voltage;
- one wire for the sender to send data to the receiver on (transmit line for the sender);
- one wire for the receiver to send date to the sender on (receive line for the sender).
Serial Buffers and Control of the Port
An area in memory where they store incoming data from the serial ports called a serial buffer.
Serial ports can only be controlled by one program at a time.
You’d need to close the serial monitor to open the port from Processing or any other application.
Topic: Microcontrollers, Digital I/O, Analog Input
· 5V vs. 3.3V
- 5V was popular, but
- 3.3V became popular.
· Micro Controller
- General purpose in/out = GPIO
- Int = text name
- Float = number
- Floating pin = 1/0 alternatively
- Pull up / Pull Down always follow smaller resistance.
- ~ -> analog write
Topic: Electricity
Why regulator blown up after certain time?
- Regulator : when all are connected with one connection – resistance = 0, blown up.
- Red = high, Green = Ground
· Multimeter – to make sure it’s safe to protect the kit.
- How to calculator minimum Res?
- V = R x A
Every component… -> Electricity -> into certain energy form.
e.g) Elec -> ligh / Elec - > heat etc…
Motor vs. Servo motor
- Yellow – signal line – requires a pulse
- Others for power.
** Try something complex **
e.g) As you start doing others, it will help you to be advanced.
e.g) As you practice a complexed version, you will get a idea for Mid term clearly.
https://itp.nyu.edu/physcomp/lessons/microcontrollers-the-basics/
Microcontroller: The simplest computers are those that are designed to take inout from the physical world and control output devices in the physical world.
Sensor: input circuits
- Sensors convert various forms of physical energy into electrical energy, allowing microcontrollers to read changes in the physical world.
Actuators: output circuits
That program is programmed onto the controller from a personal computer using a dedicated hardware programming device.
bootloader is a firmware program that lives in a part of the controller’s memory.
you need to know not only what the current state of the button is, but you also need to remember the state of the button the previous time you read it. This is called state change detection.
https://itp.nyu.edu/physcomp/lessons/sensors-the-basics/
Sensors
Switch: converts mechanical energy (e.g, your finger’s press) into electrical energy by closing a connection between two metal contacts.
potentiometer: a metal contact called a wiper slides along a resistor, effectively short circuiting the resistor (related video) into two halves and creating a voltage divider circuit.
Resistive Sensors: changing electrical resistance by using a variably resistive material at their heart.
Optical Sensors : light sources.
Ranging Sensors : by sending out a pulse of light or sound and reading the reflected signal when it bounces off a target
Programming
https://itp.nyu.edu/physcomp/lessons/variables/
setUp() -> run one time.
loop() -> run repeatly.
int -> same as LET in JS. / const int -> same as CONST in JS.
long = numeric variable. Especially for bigger number.
Float = numeric variable
map(input from, input to, range1, range2); -> mapping the input range.
if you wanted to know the voltage on an analog input pin at any point:
voltage = sensorValue * (5.0 / 1023.0);
The key to detecting state change is the use of a variable to save the current state for comparison the next time through the loop.
lastButtonState = buttonState;
Topic: Introduction Fantasy Device
Syllabus:
https://itp.nyu.edu/physcomp/syllabus/
* Introducing the class materials and what is expected.
* Why is P.Comp a core class?
- Understanding all the computing is somehow physical communication.
* Write down what worked, and what didn’t work as well.
(You will learn most of the lesson from what didn’t work.)
* Electronic = conveying information & Logic
Useful Resorces:
Where to buy kits
https://www.adafruit.com/
https://www.sparkfun.com/
https://www.digikey.com/
In Class
* Fantasy Device
- What would the fantasy device’s controller look like?
- How would you let people who never have experienced the controller know how to use it?
- Consider the visual communication, guiding the user to use it properly.
- What would be problem? what would be needed?
-> Smell tracker
- A device capturing the smell.
- Sharing the information with people in a visual or numeric information, so people can see the smell with the data.
Reading
** Basic understanding of Electricity
https://itp.nyu.edu/physcomp/lessons/electronics/electricity-the-basics/
https://itp.nyu.edu/physcomp/lessons/electronics/understanding-dc-power-supplies/
https://itp.nyu.edu/physcomp/labs/components/
https://itp.nyu.edu/physcomp/labs/electronics/
https://itp.nyu.edu/physcomp/labs/breadboard/
https://itp.nyu.edu/physcomp/labs/switches/
Electricity = the flow of electrical energy.
- two elements: a power source and components that convert the electrical energy into other forms of energy.
Sensor
- components that convert other forms of energy into electrical energy so we can read the changes in those other forms
Actuator
- components that convert electrical energy into other forms.
Transduction
- process of changing one energy into another.
Voltage - electrical potential energy.
Current - low of electrons. ( Amperes )
Resistance- ability to oppose the flow of electricity ( Ohms )
Load – Energy into other form of energy.
Short Circuit – x load -> wire will die
Q: then the Devices using AC has to be symmetry in terms of structure?
I understand DC flows in order, but AC flows are reversed.
Schematic diagrams
- images of flow of electronicity.
- Ground terminal – where the loop finishes.
- the point of lowest energy, or ground.
- This diagram shows the flow of energy from the top of the diagram to the bottom.
Component:
Conductors are materials through which electrical current moves freely.
Insulators are materials which prevent the flow of electricity
Resistors resist the flow of electricity.
Capacitors store up electricity while current is flowing into them.
Diodes permit the flow of electricity in one direction
Q: only DC can use Diode?
Volts = Amps x Ohms
or
V = I x R
Watts = Volts * Amps
or
P = V * I
Current tends to follow the path of least resistance to the ground.
In any given circuit, the total voltage around the path of the circuit is zero.
Q: means that… we should plan to use all the voltage in the path?
total resistance is equal to the sum of all the resistors in series.
For resistors in parallel, the voltage across them is equal, but the current is divided between them. The divided current across the parallel resistors is equal to the total current. So I1 + I2 = Itotal.
1/Rtotal = 1/R1 + 1/R2 + 1/R3
** resistors divide voltage when in series, and divide amperage when in parallel.
anode of the LED connects to voltage / cathode connects to ground.
- Resistor
Resistors resist the flow of electrical current. When placed in series, they reduce the voltage, and limit the current.
- Potentiometers are variable resistors.
- Transistors act as electronic switches
Q: Regulator – if I use 5 power and 5v regulator, does it just pass through it or still get influenced by regulator?
· Remember, in any circuit, all of the voltage must be used up. Why? If the voltage across all the components doesn’t add up, that indicates to you that some of the electrical energy is getting converted to light, heat, and other forms of energy. No component is 100% efficient, so there’s always the possibility for some loss.