Transcript Critical Design Review

CCLES
Computer Controlled Laser Engraving System
Group 13
Han Ly (CpE)
Jose Rivera (CpE)
Juan Pumarol (EE)
Brandon Workman (CpE)
What is CCLES?
The Computer Controlled Laser Engraving System will be capable of
taking an image from a computer program, that is written specifically
for this project, and pass it into an engraver. The CCLES will translate
the image data and laser engrave it onto the wood. The end result that
is engraved into the material should mirror the image that was
processed by the program. The project itself is a standalone system,
excluding an initial computer to transfer an image to the engraver.
Motivation
• The inspiration for this project is derived from trying to develop a
quick and autonomous system that is user friendly for doing custom
work.
• This project is hobbyist friendly for personal use since the end goal is
to develop a relatively cheaper alternative than buying an industrial
engraver.
• In addition, a major goal is to develop a system that is somewhat
generic and have the ability to scale its applications. This allows users
to develop a line of projects that can be built on this system.
Constraints
• Economic – The project is funded by the group members in its
entirety. The final total for the project shouldn’t be more than
$700 which would make unfeasible for hobbyists.
• Time – Reduced development time due to summer term.
Additional features can’t be developed due to a shorter term.
• Health and safety – Lasers are classified in various classes to
provide safety guidelines. Another issue that occurs is that
when burning material fumes are created.
Laser Health and Safety
• Class I – No possible eye damage due to low power output.
• Class II – Output power up to 1 mW, emits visible light, blink
reflex of the human eye prevents damage.
• Class IIa – Specific low power range that requires 1000
seconds of viewing to damage the retina.
• Class IIIa – Up to 500 mW power output and uses optical
instruments to change diameter or power density.
• Class IIIb – Lasers are generally dangerous to view, but the
diffusion is safe.
• Class IV – Over 500 mW, beam cam cause severe damage to skin
or eyes. Diffusion is dangerous within the nominal hazard zone.
Specifications
Parameter
Description
CCLES
Should take less than 20 minutes to complete a job
Frame
Must be less than 22 kg
Frame
Must be smaller than 1 m x 1 m x 1 m
Laser
Output should be at least 1 W
Driver Controller
Program size must be less than 256KB
Material
This system is designed to be able to engrave in soft wood
Working Area
This system should maximize the entire working area of the
frame
Image
The accepted data type for user program should be PGM
Power
This project must be powered by a 120 VAC source
Hardware Block Diagram
Computer Controlled
Laser Engraving System
XY Plotter
Stepper
Motors
Motor
Driver
Laser
Microcontroller
DC Power
Supply
Laser
Driver
Hardware Block Diagram
Computer Controlled
Laser Engraving System
XY Plotter
Stepper
Motors
Motor
Driver
Laser
Microcontroller
DC Power
Supply
Laser
Driver
Frame –XY Plotter
• Plotter operates in two
dimensions
• Dual-way transmission for
improved stability and
precision
• Working area of 310mm x
390mm
• Manufactured and distributed
by Makeblock at $209.99
Motors
• Stepper motor vs. servo motor: stepper motor is best suitted for this
project:
• Cheaper than servo motor
• Higher torque at low speed
• Rugged and required no maintenance
• Resolution is independent between stepper motor and its driver
• High precision for positioning control
42BYG Stepper Motor
• NEMA 17 standard, hybrid
bipolar stepper motor
• 2 phases
• Step angle of 1.8 degrees ± 5%
• Rate voltage of 12v and current
of 1.7A/phase
• Manufactured and distributed
by Makeblock at $19.99
Reprinted from DRV8811
datasheet provided by
Texas Instruments
ME Micro Switch B
• Physical switch sends signal to
the controller when triggered
• Rated voltage: 250 VAC
• Rated current: 5A
• Switching life minimum
1,000,000 cycles
• Mounted on X and Y axis
• Manufactured and distributed
by Makeblock at $2.99
Me 2H Microstep Driver
• Input voltage from 12VDC and up to 36VDC
• Output current from 0.44A ~ 2.83A
• Overvoltage, under voltage, over current, phase
short circuit protection
• 8 step modes: 1/2/4/8/16/32/64/128
• 8 channels output phase current setting
DRV8811: Stepper Motor Controller IC
• Pulse width modulation (PWM) micro-stepping motor driver
• Built-In Microstepping Indexer
• Simple step and direction control interface
• When the system is idle, the driver will activate low-power sleep
mode by the MCU to prevent unnecessary overheating and reduce
power consumption.
• The current regulation is configurable, with three decay modes of
operation: fast, slow and mixed
DRV8811
• Powered by a supply voltage between 8 V and 38 V
• Output current up to 1.9 A per winding.
• Overvoltage, under voltage, over current, phase short
circuit protection
• 4 step modes: 1/2/4/8
• Motor supply voltage range also from 8 – 38 V
• Logic power supply voltage range from 3 – 5.5 V
• Manufactured and distributed by Texas Instrument as
free sample with student emails.
DRV8811 Modified Reference Diagram
Reprinted from DRV8811 datasheet provided by Texas Instruments
Drivers
Hardware Block Diagram
Computer Controlled
Laser Engraving System
XY Plotter
Stepper
Motors
Motor
Driver
Laser
Microcontroller
DC Power
Supply
Laser
Driver
MCU Comparisons
Feature
ATmega32U4
MSP430fg4618
TM4C123GH6PM
Core
AVR
MSP430
ARM Cortex-M4F
Performance
16 MHz
8 MHZ
80 MHz
Flash
32 KB
116 KB
256 KB
SRAM
2.5 KB
8 KB
32 KB
USART
1
1
8
PWM
4
0
2
I2 C
0
1
4
SSI
0
0
4
GPIO
0
0
43
MCU Schematic
UART
• The UART will be used to establish communication between a
computer and the microcontroller.
• Reaches speeds of 5 Mbps on regular operation, 10 Mbps on high
speed.
• Chosen due to the familiarity from previous classes:
• Have existing code to help establish a connection
• Understanding of how it works
• This project will be configured for a baud rate of 115200, serial, 8 data
bits, 1 stop bit, and no parity or flow control
2
IC
• A bi-directional data transfer protocol that has standards that are
predefined
• Multiple devices can be managed with a single bus
• Four I2C modes exist but the configuration for this project will be
Master transmit for laser
• Transmissions speeds vary from 100 Kbps to 3.33 Mbps
2
IC
vs SPI
• I2C requires two wires for operation opposed to SPI which can be 3 or
4
• I2C draws more power
• SPI is faster compared to I2C
• SPI can’t transmit off the PCB while I2C can
• I2C is less susceptible to noise than SPI
• SPI lacks formal standards compared to I2C
Communication Overview
UART
MCU
PWM
Motor
Drivers
PWM
Laser
Pulse Width Modulation
• This is a method of coding digital signals into an analog waveform,
this is very useful for controlling the frequency and duty cycles of
things that require clocks.
• This project will utilize three PWM modules: 2 for stepper motor
drivers and one to drive the enable for the laser.
• The stepper motor drivers require at least one microsecond of an
active high to cause a step to occur.
Pulse Width Modulation Output
Hardware Block Diagram
Computer Controlled
Laser Engraving System
XY Plotter
Stepper
Motors
Motor
Driver
Laser
Microcontroller
DC Power
Supply
Laser
Driver
Laser Subsystem
•
•
•
•
The laser subsystem was constrained due to costs.
The system will be able to engrave wood.
Must be low cost.
Take up minimum space
Laser type
Power output
Expected cost
YAG
40 W
$1000+
CO2
20 W
$500+
Diode
3-4 W
$40-$100
Laser Diode
• Current driven devices.
• M140 Laser Diode was selected.
• NDB7875 is a replacement candidate.
NDB7875
Wavelength
Opeating Current
Power output
Diameter
Cost
M140
445 nm
1-2.4 A
1-3 W
9 mm
$60
Wavelength
Opeating Current
Power output
Diameter
Cost
445 nm
1-1.8 A
1-2.2 W
5.56 mm
$42
Diode Host and Mount
• Copper and aluminum host for heat
conductivity.
• Ribbed aluminum mount to act as a heat
sink.
• Laser diodes have large divergence at the
output.
• A glass lens is required to collimate the
laser output.
• 405-G2 Glass lenses are used for the diode.
Step Down Transformer
• 183k24 – 56 VA Transformer from Hammond
Manufacturing.
• Cost – $18.09.
• Bridge rectifier for full wave rectification.
• 33,000 uF smoothing capacitor.
• LM2576 switching regulator designed for
16 V output with an efficiency of 85-90%.
• Contained in a Hammond 1591ESBK ABS
Project Box Black.
• IEC inlet attached to the box with a power
switch a fuse receptacle containing a 250V
3A rated fuse.
Step Down Transformer
Laser Driver – LM3406
• Manufactured by Texas
Instruments.
• Reference design
provided by WEBENCH.
• Simple design, low
external parts, enable
line.
• 16 V input, 4.8 V and 1.2
amps output.
Voltage Regulators – Block diagram
Efficiencies
TPS563200 – 3.3V
92.9%
TPS563200 – 5V
89.9%
TPS54531
96.6%
Image provided by Texas Instruments
WEBENCH Designer.
Voltage Regulators - Schematics
PCB
Software Block Diagram
User Computer
Computer Controlled
Laser Engraving
System
Graphical User
Interface
Driver Controller
Programming
• Programming Language:
• Java – This language was used to program the graphical user interface that
the user will be interacting with.
• C – This language was used to program the driver controller that will handle
the motors and laser.
• Programming Environment:
• Eclipse – This environment was chosen to develop the Java program.
• Code Composer – This environment was chosen to develop the C program.
Graphical User Interface
• The GUI is the main system the user will be interacting with when
operating the machine.
• The GUI allows the user to draw a custom image that can be etched
on to a chosen material.
• Other options offered by the GUI:
• New Image
• Save Image
• Open Image
Flowchart
• Initializes the user interface
window then waits and listens
for user input.
• If a menu option was selected,
the program checks for and
reacts to the chosen option.
• When engraving, the program
iterates through each pixel until
finished.
Class Diagram
Driver Controller
• The Driver Controller will be a program running on the
microcontroller.
• The program will be controlling:
• Two motors
• Laser
• The program will be using UART with interrupts to receive and
transfer data to and from the main computer.
• The program will be running in an infinite loop keeping track of the
current position of the laser.
Flowchart
• Initialize the I/O pins and wait
for data from the main
computer.
• When data is received, check to
see if it is valid and react
accordingly.
• When a coordinate is received,
go through a process to etch at
the given spot.
Class Diagram
• Initializes the microcontroller
pins used or input an output.
• Controls the movement of the
laser in the 2-D grid with the
motors.
• Controls when the laser turns on
and or how long.
Work Distribution
Juan
Laser Driver
X
Motor Driver
O
Power Systems
X
PCB
X
Jose
Han
X
O
Brandon
O
MCU PWM Programming
X
O
MCU Pin Programming
X
X
MCU UART
X
O
JAVA UART
X
JAVA GUI
X
X = Primary
O = Secondary
Progress
CCLES Progression
Research
100
Frame
100
MCU
98
Power
100
Software
95
Testing
90
Total
93
0
20
40
60
80
100
% Completion
Budget
Part
Quantity
Cost
Makeblock XY Plotter
1
$209.99
M140 Laser Diode
1
$42.00
Laser Host
1
$5.34
Laser Heatsink
1
$3.50
405 G-2 Lens
1
$30.00
LM3406 Sub-system
1
$1.39
TPS563200 – 3.3V Sub-system
1
$1.39
TPS563200 – 5V Sub-system
1
$1.08
TPS54531 Sub-system
1
$2.14
183k24 – 56 VA Transformer
1
$18.09
TMC123GH6PMI7
1
$11.42
DRV8811 Sub-system
2
$10.40
LM2576
1
$1.70
Hammond 1591ESBK ABS Project Box Black
1
$7.45
Inlet Male Power Socket with Fuse Switch 10A 250V 3 Pin IEC320 C14
1
$4.41
PCB Manufacturing
1
$40.00
TOTAL
$390.30
Questions