Prof. Andy Khong Rachel Fong Li Xuan Law Cai Jin Shilpa ... · Prof. Andy Khong Rachel Fong Li Xuan...
Transcript of Prof. Andy Khong Rachel Fong Li Xuan Law Cai Jin Shilpa ... · Prof. Andy Khong Rachel Fong Li Xuan...
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Prof. Andy Khong Rachel Fong Li Xuan Law Cai Jin Shilpa Manandhar Soumyabrata Dev Assistant Chair (Outreach) Assistant Manager (Outreach) Sr. Assistant Manager (Outreach) PhD Student PhD Student
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2014 Nobel Prize for Physics
Nobel prize is meant to reward inventions of greatest benefit to mankind
A trio of scientist was awarded for their invention of efficient blue light-emitting diodes (LEDs)
1. Highly energy-efficient white LED lamps contributes to saving the earth’s resources
2. Without blue LEDs, our smart devices wouldn’t have backlit liquid crystal display screens (LCD), which are built with LEDs.
3. Providing light to people without electricity by using solar-powered LEDs
4. Sterilizing polluted water using ultraviolet LEDs, made possibly by blue LEDs
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Significance
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Incandescent Bulb Compact Fluorescent LED
60 watts 14 watts 10 watts
1,200 hours 10,000 hours 50,000 hours
Advantages of LED • No warm up period required : Light up instantly in nanoseconds • Controllable: Brightness and colour • Environmental Friendly: Does not contain mercury or other hazardous
substances • Long lifetime : 50,000 hours
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LED Cube
3D Animation: INFORMATION
ENG. & MEDIA
Transistors:
ELECTRONICS
Micro-controller:
COMPUTER ENG.
LEDs:
PHOTONICS
Electrical Circuit:
CIRCUIT DESIGN
Programming:
SOFTWARE ENG.
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Analogy
Programming Codes
Upload
Arduino Microcontroller
= =
Conductor Music Score =
LED Animation
Direct
Performance
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BUILD LED CUBE Hardware testing
LED ANIMATIONS Programming on Arduino
BUILD LED CUBE Soldering of LED panels Solder panels to PCB
INTRODUCTION Components Circuit design
HANDS-ON Set up Arduino board Breadboard
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Components
LED Resistor Transistor
Arduino Breadboard
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Diodes
Forward Bias: Allows current to flow from Anode to Cathode Reverse Bias: Current is blocked which results in no flow of electricity in the circuit When current is flowing through a diode,
Vanode > V cathode
A diode with arrows representing light emitted. Conditions for LED to work: 1. Has to be oriented properly ( this is called polarity) 2. Vanode > V cathode typically between 1.4 to 3.5 V.
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Light-Emitting Diode (LED)
Typical current of 10 to 20 mA. The higher the current, the brighter the LED.
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Top view Side view
Anode or Cathode?
Test your LED
Diode Test
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Anode Cathode
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Resistor
Do not directly connect an LED to power source LEDs can be damaged by high current. Resistor is added in the circuit to limit current flowing through the LED.
An electrical component that limits or regulates the flow of electrical current in an electronic circuit.
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How to get resistance value?
Colour Coding Table
Measure Resistance
How much is the resistance value?
Digital Multimeter
100Ω with ± 5% tolerance
How to light up the LED?
If Vcc = 5 V, what should be the resistance R for a LED current of I = 10 mA?
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Vcc=5V
I=10mA
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How to light up the LED?
Ohm’s Law: V=IR
Vcc=VLED+IR
R=(Vcc-VLED)/I
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Calculate R for LED Color VLED(V) R (Ω)
2.00 300
1.98 302
3.24 176
3.06 194
Vcc=5V
I=10mA
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In our LED cube, the BJTs are acting as switches, either enabling or disabling the corresponding layers of LEDs to be lighted up.
Bipolar Junction Transistors (BJT)
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3 Pins Collector (C) Base (B) Emitter (E)
Microcontroller
1x USB port to talk to the computer, double as power supply; 1x dedicated power port, for use without computer; 14x digital input/output pins (D0 - D13) 6x analog input pins (A0 - A5, double as digital outputs if needed) Power and Reference pins 18
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How LED cube works
Only 20 usable pins to control LEDs We have 4x4x4=64 LEDs in the cube
How to control 64 LEDs with only 20 output pins?
A0-A5
D0-D13
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Anode
Layer 1
Layer 2
Layer 3
Layer 4
Cathode
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Anode
Layer 1
Layer 2
Layer 3
Layer 4
Cathode
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Layer 1
Layer 2
Layer 3
Layer 4
Cathode
Anode
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Anode
Layer 1
Layer 2
Layer 3
Layer 4
Cathode
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Main Concepts
Persistence of vision (POV) Optical illusion that tricks our human eyes By flashing a LED really fast, the image will remain
on the retina for a short time(approx. 0.04s) E.g. Flipbook
Temporal Multiplexing Time Division Multiplexing (TDM) Transmit and receive independent signals over a
common signal path Use transistors to turn on each layer at a different
time frame By flashing each layer of the LED one after another
real fast, it gives a optical illusion of a 3D image
Steps:
1. Build circuit
2. Connect A2 pin(5V) or GND(0V) to Vin
How does it work?
1. To turn on LED, Vin = 5V
2. Set Pin x at 0 or 5V to turn off or on the respective LED
(100-400 ohm)
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Vin Vin=5V, Close
Vin=0V, Open C E
C E
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Breadboard To build and test circuits before finalizing any circuit design
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- Cathode + Anode
Vin
Vin=5V, Close
Vin=0V, Open
C E
C E
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Hands on for Breadboard
Setting up Arduino Board
1. Connect board to PC via USB cable
2. Check COM port number
Control PanelSystemDevice Manager
Ports
Note down COM #
3. Select your board
Double-click Arduino app
ToolsBoardArduino Uno
ToolsSerial PortCom #
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Open the Arduino code: AllOn.ino
How do we get this value?
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Verify Upload
Turn ON all LEDs
Computer talks in Binary (0’s or 1’s)
What is computer language?
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0V (Ground)
5V (Supply voltage)
0 (Low)
1 (High)
1 1 1 1
Binary Decimal
1x23 +1x22 + 1x21 + 1x20 = 15
Speaking the Computer Language
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1x23 +0x22 + 1x21 + 0x20 = 10
1 0 1 0
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Lighting Sequence
Frame 1:
Frame 2:
Frame 3:
Frame 4:
Frame 5:
Add comma before adding next frame
No comma for last frame
Change frame rate here
Open the Arduino code: Sequence.ino
Can you generate these LED patterns?
Frame rate per second =1
Frame 6:
3 2 1 0 Pin
Frame 7:
Frame 8:
Frame 9:
Frame 10:
Frame 1:
3 2 1 0 Pin
Frame 2:
Frame 5:
Frame 3:
Frame 4:
1. Open Sequence.ino 2. Save as MyPattern.ino 3. Modify code
4. Save file 5. Click to verify code 6. Click to upload
STEPS:
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Effect of Frame Rate
Blinking Pattern
Vary the frame rate from 1 fps to 300 fps.
When does the blinking disappear?
Why does it happen?
Frame 1:
Frame 2:
3 2 1 0 Pin
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BUILD LED CUBE Hardware testing
LED ANIMATIONS Programming on Arduino
BUILD LED CUBE Soldering of LED panels Solder panels to PCB
INTRODUCTION Components Circuit design
HANDS-ON Set up Arduino board Breadboard
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Building LED Cube Printed Circuit Board (PCB) is a plastic board with copper tracks that link up fixed components to form a circuit.
Front Back
Soldering joins two pieces of metal, such as electrical wires, by melting them together with another metal to form a strong bond.
Soldering iron is very HOT!
> 300C!
Soldering Tips
Secure the LED panels with Blu-Tack.
Hold the soldering iron firmly.
Do not catch if soldering iron drops!
Put the iron back securely whenever you are not soldering.
Keep the iron tip clean by wiping on the damp sponge.
Apply solder to the joint by heating it with the soldering iron.
Solder should appear to flow onto wires to be connected.
Note that joint remains hot after soldering!
Wash your hands after soldering! (Excessive LEAD is harmful to your health)
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Soldering
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LED Cube 4 MAIN STEPS
Cathode
Anode
Solder a row of 4
LEDs
Solder 4 row of 4
LEDs into a panel
Solder panels
onto PCB
Solder cathode in
a layer together
LED Panel
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LED Panels
Components Quantity (1 panel) Quantity (LED cube = 3 panels)
LED 16 16 x 3 = 48
Tinned copper wire
8 8 x 3 = 24
Here are the components needed:
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Anode Cathode
NOTE: Test 4 LEDs at a time before soldering
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Placement of wires connecting anodes
Trim horizontal wires Orientation of LED Cathode (below) Anode (top), bend CCW 90°
Pla
cem
ent
of
wir
es
con
ne
ctin
g ca
tho
de
s
Alignment Sheet
Position of PCB (Do not Trim)
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LED Panels
Check connections Seek for assistance if the LED does not light up
Is the LED working?
Horizontal Plane: Cathode (-ve)
Vertical lines: Anode (+ve)
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Solder 4 panels onto PCB Connect up cathodes of each layer Connect cathodes to BJTs
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Solder 4 panels onto PCB
1. LEDs facing front 2. Anode lead(Bended 90°)facing down 3. Align 4 panels to form a cube 4. Solder 5. Trim off excess vertical wires Note: Seek for assistance before trimming the wires
Solder cathodes together
Refer to display sets
STEPS
BJT
PCB
Align PCB surface with this line
BJT
PCB
Align PCB surface with this line
BJT
PCB
Align PCB surface with this line
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Panels
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1. Seek assistance to install Arduino Board on PCB
2. Upload DebugCube.ino to lights up one LED in sequence from bottom to top layer
3. Identify LEDs that are not lit up
4. Identify poor connection & re-solder the joint
5. Inform instructor when testing completed
Hardware Testing
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BUILD LED CUBE Hardware testing
LED ANIMATIONS Programming on Arduino
BUILD LED CUBE Soldering of LED panels Solder panels to PCBs
INTRODUCTION Components Circuit design
HANDS-ON Set up Arduino board Breadboard
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1. Open AnimationTemplate.ino
2. Save file as yourname01.ino in “Student” folder
e.g. kengying01.ino, kengying02.ino etc
Remember to save your file after editing!
Feel free to copy the file for future use
STEPS:
Make your animation
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3. Create own animation at : http://www3.ntu.edu.sg/home2012/SOUMYABR001/ledcube.html
Copy this segment
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Paste your codes here
{0, 0, 0, 65535}
Layer 1 (bottom)
Layer 2
Layer 4 (Top)
Layer 3
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4. Run animation at different speed
Set initial frame rate
Change frame rate
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5. Verify () & Upload ()
Error messages shown if mistakes found.
Verify
Code verified.
Upload
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Take Away
1. LED only lights up with the correct polarity 2. Solder likes HEAT 3. Motion is seen when static images are presented in quick sequences 4. Persistence of vision (POV) 5. Temporal Multiplexing Official website of Arduino with tutorials, references and fun projects: https://www.arduino.cc/
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