Joel Meisinger
Harout Hedeshian
Frankie Ning
Dominic Boiko
Ching-Han Tseng
1


Inputs
Job File
User
Controls
Outputs
3D
prototype

Status


Design of a 3D printer for
affordable prototyping.
Prints each cross section
of a 3D object layer by
layer
Three axis motion in a
2x2 feet chassis for large
scale modeling
Use of accurate stepping
motors for high precision
printing
Network communication

Low Level:
 Position printer head from
basic raw commands
 Layout material
 Display printer status

Mid Level:
 Print Simple 3D objects
 Position Feedback

High Level:
 Print objects base on STL

Printer Objective
Resolution
 25mm/s linear write speed
 0.5mm deposition
resolution
 5mm3/s (0.3 in3/s)
 Capable of printing a 10cm3
object
 Capable of printing
functional prototypes
job files
 Independent power
system
3
Electrical
Power
System
Command and
Data Handling
RS422 Bus
Stepper I/O
Position
Motor
Sensing
Controller
Controller
Interrupt
Material
Deposition
Controller
Power
RS422
Interrupt
GPIO
4
Electrical Power System
5
Provide each sub-system with appropriate power level
Isolated Power System
 Reduced Shock Hazard
 Continuity of power
 Noise Reduction
Open and short circuit protection
Function Decomposition
Transformer Design
EMI Filter
Rectifier
Bridge
Feedback
Isolated
Wall
Outlet
120VAC
5V Forward
converter
(Isolated)
Transformer/
Reset
Winding
FPS
CDH
MDC
12V
Forward
converter
(Isolated)
PSC
SMC
Metallic Enclosure For Grounding
Relay(Enable)
•Open Circuit
Snubber Circuit will be implemented by the transformer and output to
prevent “inductive kick” effect.
Bleed Resistor for discharging capacitor and prevent OC.
•Short Circuit (FPS IC)
Latch Mode Protection: FPS shuts down SMPS till AC power is reconnected
Auto Restart Mode Protection: Under Voltage Lockout(UVLO)
•Other
Overload Protection
Over Voltage/Current Protection
Metallic enclosure grounding
Module
Inputs
Outputs
Functionality
EMI Filter
120VAC from Wall outlet
120VAC to Rectifier
The process that filters out high frequency noises comes in from the wall outlet.
EMI dedicates a return-path especially for noises, and therefore greatly reduces the
unwanted spike when proceeds.
Module
Inputs
Outputs
Functionality
Full-Wave Rectifier Bridge
EMI Filter
170VDC with approximated voltage ripple to FPS
The function that generates full positive waves. The smoothing capacitor, locates at
the output of the rectifier, converts the full-wave rippled output of the rectifier into
a smooth DC output voltage.
Module
Inputs
Outputs
Functionality
FPS (Power Switch)
170VDC from Rectifier, Isolated Feedback from output
Primary, Reset, Vcc and Secondary windings on the transformer
The FPS has the internal switching frequency of 67KHz on MOSFET to makes DC-DC
converter. It requires about 15VDC on Vcc winding to drive the chip and startup
various functions.
Module
Inputs
Outputs
Functionality
Transformer
FPS
5VDC, 12VDC Converter
Base on the turn ratio on the windings, this module may step up or down on
voltage
Module
Inputs
Outputs
Functionality
DC-DC converter
Transformer
5VDC, 12VDC rail to each subsystems
With manipulations on passive parts, these modules output desired voltage rail and
current.
Module
Inputs
Outputs
Functionality
Feedback
5VDC, 12VDC rails
FPS
This module supplies or reduce amount of gains to stabilize the output in case of
any drastic changes.
Primary risk:
•Hand-made Transformers might not operate as ideal as the calculation
•Fall back to more detailed analysis, calculation, component upgrade, and proper
circuit protection
•Over-current/short current protection, metallic enclosure grounding and isolation
are part of considerations to prevent this hazard
 Goal
•Redesign Transformer and find the better ferrite core
•Fully test out the circuits on the perf-board
•Power management
•Proper debug/Test procedures documented
•PCB
Command and Data Handling
14




Coordinate all events
on printer
Communications
interface for daughter
boards
Provide a physical
human interface for
high level control
Platform independent
and driverless
communications to
host computer
Not populated on Rev A
DEBUG
EPS
5V
RS232
Power
Sequencing
SRAM Data
Buffer
5->3.3 Buck
5->2.5 Buck
ARM Cortex M3
(Stellaris LM3S6965)
Main CPU
I2C
USB>RS232
RS232
Ethernet
LCD
SPI
4Mb
AVR MCU
(ATXMEGA128A1)
IO Hub
CY8C9560A
GPIO
Expander
Buzzer
Not populated on Rev A
Button
s
RS422
Driver
RS422
Driver
RS422
Driver
Reset lines
6-DIN
6-DIN
6-DIN
Module
Inputs
Outputs
Function
ality
Buck Converters
5VDC
3.3VDC, 2.5VDC
Take 5V from the power bus and step it down to 3.3V and
2.5V noting the correct power up sequence.
Module
Inputs
Outputs
Function
ality
ARM Cortex M3 LM3S9595
USB, Ethernet, COM from AVR
LCD, COM to AVR
Primary processor on 3DP responsible for interfacing 3DP
to the real world. Process vectors and coordinate
subsystems.
Module
Inputs
Outputs
Function
ality
SRAM Buffer
Address, Data
Data
Space to store circular buffers of packet data for relay and
transmission, and retransmission
Module
Inputs
Outputs
Function
ality
AVR MCU
COM from CDH, I2C from CY8C9560A, COM(0-3)
COM to CDH, I2C to CY8C9560A, COM(0-3)
Responsibly for ensuring reliable message packet delivery
between all subsystems. Also relay button presses and
sends back to CDH
Module
Inputs
Outputs
Function
ality
CY8C9560A
I2C from AVR MCU, Buttons
I2C to AVR MCU, Buzzer
Encodes buttons and drives buzzer. I wanted to play with
this chip.

Stellaris:
 FreeRTOS
 uIP
 Web server
 Using a highly
modified Telnet server
implementation to
provide raw TCP
socket for
communication.
• XMEGA:
– Mostly interrupt
driven custom
firmware
– Simple functionality
acting as a “smart”
I/O controller.
– Nobody has ported
an RTOS to the
XMega?!
RTOS Kernel Managed Tasks
LCD
Message
Queue
uIP
HTTPD
MAC
Management
Interrupts
System Tick
TELNET
Ethernet
Shell/Protoco
l
Lots of
Cool
Blinking
LEDs
Event
Dispatch
USB/UART
COM
Main Loop
Interrupts
LED Management
System Tick
COM1
Keypad
COM2
Message
Routing
COMV1
AVR
Management
COM3
COM4


Original risks from PDR:
Primary risk: Ethernet non-functional
 Working

Secondary Risk: USB-UART non-functional
▪ Working
 New risks:
▪ Getting bored and making LEDs blink in funny patterns
Material Deposition Controller
Joel Meisinger
23

Objective
 Keep constant print head tip temperature
 Keep constant torque on fed printing material

Requirements
 Supply consistent material delivery to the printing
area(.5mm diameter +/- .1mm)
 Be able to start and stop printing material reliably.
 Notify CDH(main system) when print head is up to
temperature and ready to print or when the
printer out of material.
24
25
EPS
RS232
Debug
5V
12V
3.3V
DC/DC
converter
5V DC/DC
converter
MDC
XMEGA MCU
Deposition
Motor
Driver
RS422
Driver
Deposition
Thermal
Driver
CDH
Micro data lines
Power
Print head control
Print head
Thermal
Feedback
26
Module
Inputs
Outputs
Functionality
Module
Inputs
Outputs
Functionality
Module
Inputs
Outputs
Functionality
Module
Inputs
Outputs
Functionality
3.3V DC/DC Converter
5V supplied from EPS, DGND
3.3V
Provides power for Xmega MCU and
drive signal to motor driver
controller. Low current
requirement.
5V DC/DC Converter
12V supplied from EPS, AGND
5V
Provides power to motor driver
controller/stepper motor. High
current requirement.
RS232 Driver
Xmega TX and PC TX, DGND
Xmega RX and PC RX
Debug port for Xmega and
development environment.
RS422 Driver
Xmega TX and PC TX, DGND
Xmega RX and PC RX
Communication driver between
CDH and XMEGA for drive
commands.
Module
XMEGA MCU
Inputs
3.3V, DGND, RS422 TX(CDH),
Thermal feedback
RS422 RX(CDH), Motor Driver,
Thermal driver
Controller for the material
deposition unit/print head.
Regulates temperature and
constant torque for the material
feed.
Outputs
Functionality
Module
Inputs
Outputs
Functionality
Module
Inputs
Outputs
Functionality
Thermal Driver
12V, AGND, drive signal
PWM Power to the print head
nozzle.
Drives the heater on the print
head.
Motor Driver
5V, AGND, drive signal
Stepper motor driving signal.
Drives the motor to feed the
deposition material.
27
MDC
Main
Init_sys()
Init_CLK()
Init_IO_PIN()
Init_USART_RS232
Init_USART_RS422
Init_Timer0( )
Packet
Handlers
read_packet(…)
write_packet(…)
Motor
Drive
SM_Drive(…)
QDEC_EVSYS(…)
QDEC_Index(…)
PWM
Temp
Drive
PWM_Rate(.)
Temp
Sensor
adc_read(…)
LED
LED_On(…)
LED_Off(…)
28

Print-head is completely custom.

Thermal controlled brass tip heated by
NiChrome wire at temperatures 221°F 300°F

ABS plastic: Possesses outstanding impact
strength and high mechanical strength
making it well suited for working mechanical
parts.

Stepper motor with feed gear that will supply
constant torque(TBD).

Compact having the ability to adapt to most
3d axis systems. 12 square inches.
29
•
•
1.
2.
ABS not working for dependable deposition
Nozzle tip temperature not constant
Use other material type such as a PVC or
epoxy resin. Also try a variable torque routine
that will be suited for changing speed and
direction of the print-head when moving
from one vertices to another.
Use other tip sizes, apertures and heater
materials.
30
Position Sensor Controller
Frankie Ning
31

Objective
 Keep track of extruder head location
 Keep track of motor movements and provide limit
warnings
 Keep track of temperature on stepper motors and
motor driver heat sinks

Requirements
 Supply CDH Controller with 3 axis position of the
extruder within 1/200th of a rotation
 Supply motor status to CDH Controller
 Supply limit warnings and movement verification to
Stepper Motor Controller
32
33
RS232
EPS
ISP
RS422
PSC
CDH
RS422
6 GPIO
Driver
RS232
Driver
5V
3.3V
DC/DC
converter
Encoder
X
SMC
2 Limit
X
XMEGA MCU
Encoder
Y
Encoder
Z
2Limit
Y
Motor
Temp
XYZ
2 Limit
Z
5V
3.3V
GPIO
ADC
USART
34
Module
XMEGA MCU
Module
Encoder X,Y,Z
Inputs
3.3V, GND, RS232 TX(PC), RS422 TX(CDH), Encoder A,B, index
signals from Encoder X,Y,Z, ISP
ISP, RS232 TX(PC), RS422 TX(CDH)
Gathers data from limit, temperature, and encoder sensors.
Controls the RS232 and RS422 driver to communicate with the
PC or CDH. Also includes GPIO to SMC for temperature and
limit warnings
Inputs
Outputs
Functionality
Rotary disc in encoder
Quadrature A and B, 90o off phase
keep track of motor movement and position
Module
Limit X,Y,Z
Inputs
Outputs
Functionality
Limit flag
Quadrature A and B, 90o off phase
keep track of motor movement and
position
Module
Motor Temp X,Y,Z
Inputs
Temperature sensor mounted on stepper
motor
Outputs
Analog output 200mV – 1.75V at 10mV/oC
Functionality
keep track of motor temepratures
Module
3.3V DC/DC Converter
Inputs
Outputs
Functionality
5V
Regulated 3.3V
supply power to on board ICs
Outputs
Functionality
Module
ISP
Inputs
Outputs
Functionality
PDI_CLK, PDI_RESET, power, ground
PDI_Data,
AVRISP MkII Programming module for Xmega
Module
RS422 Driver
Inputs
Outputs
Functionality
Xmega TX and CDH TX
Xmega RX and CDH RX
Communication driver between CDH and PSC, command and
data is sent using the RS422 driver
Module
RS232 Driver
Inputs
Outputs
Functionality
Xmega TX and PC TX
Xmega RX and PC RX
Communication driver between PC RS232 and XMEGA
UART
35
PSC
Main
Init_sys()
Init_CLK()
Init_IO_PIN()
Init_USART_RS232
Init_USART_RS422
Init_QDEC( )
Init_Timer0( )
Packet
Handlers
Encoder
Limit
read_packet(…)
write_packet(…)
QDEC_Direction(
…)
QDEC_EVSYS(…)
QDEC_Index(…)
Limit_detect(
…)
Temp
Sensor
adc_read(…)
LED
toggle_
heartbeat(
…)
36
US-Digital E5
Optical Rotary Encoder
 Index
 Quadrature
 512 CPR (cycles per revolution)
 2048 PPR (pulses per revolution)
 Max detectable rpm = 11718
 Fits ACME threaded rod
 2mm – 10mm or 1/8” – 3/8” shaft

Max Frequency Response 100kHz
37

Limited Funding
 Remove Encoders, reduce cost
▪ Not critical to design/ Good to have feedback
▪ Stepper motors with fine resolution
 Minimum cost PSC would include
▪ Temperature Sensor
▪ Track temperature of motors and drivers
▪ Photointerrupt Sensor
▪ Detect when print head moves to a X, Y, or Z axis limit
 Apply to EEF
 Personal donation
38
Stepper Motor Controller
39

Objective
 Control motion of extrude head along 3 axis (X,Y,Z)
 Control speeds of motors using constant current
motor drivers
 Accurate positional translations using high resolution
stepper motors as opposed to simple DC motors

Requirements
 Drive steppers motors based on instructions given by
CDH controller
 Provide current motor status when queried by CDH
 Able to drive motors accurately with enough torque
to control extrude head position
40
EPS
RS232
ISP
SMC
6 GPIO
RS232
Driver
5V
3.3V
DC/DC
converter
Motor Driver
Linear
Actuator X
XMEGA MCU
Motor Driver
Linear
Actuator Y
PSC
RS422
Driver
Motor Driver
Linear
Actuator Z
CDH
RS422
Legend
12V
5V
3.3V
GPIO
Isolated Signals
UART
Module
Inputs
Outputs
Functionality
RS232 Driver
Xmega TX and PC TX
Xmega RX and PC RX
Communication driver between PC RS232 and
XMEGA UART
Module
Inputs
Outputs
Functionality
ISP
PDI_CLK, PDI_RESET, power, ground
PDI_Data,
AVRISP mkII Programming module for Xmega
Module
Inputs
XMEGA MCU
3.3V, DGND, RS232 TX(PC), RS422 TX(CDH), ISP,
PSC limit sense GPIO
ISP, RS232 TX(PC), RS422 TX(CDH), Motor Driver
Control Signals
Communication driver between PC RS232 and
XMEGA UART, Configure motor driver operation
Outputs
Functionality
Module
Inputs
Outputs
Functionality
Motor driver TB65605AHQ
5V, 12V, AGND, motor driver control signals
PWM current waveform for 2 phase stepper motor
Take digital control signals and drive a single
stepper motor and defined torques, speeds, and
resolution.

Single 2-phase bipolar motor driver chip
 Controllable current for torque management
 Capable of half stepping and microstepping



Digital control inputs
Stepping speed determined by input clock
Success!!!
44
45
SMC
Main
init_sys()
Init_CLK()
Init_IO_PIN()
Init_USART_RSxxx
()
Init_Timer0( … )
Packet Handler
read_packet(…)
write_packet(…)
execute(…)
Motor
controller
Check limits
Set control signals
Module
Inputs
Outputs
Functionality
Main
None.
None.
Call init_sys() to bring XMEGA online. Call
read_packet() and write_packet() for interboard
communications. Call execute() on commands
received from CDH. Call the motor driver handling
functions.
Module
Inputs
Outputs
Functionality
Init_sys()
None.
None.
Initializes the clock, IO pins, USARTs, and timers.
Module
Inputs
Outputs
Functionality
Packet Handler
Packet by serial (see struct for packet)
Response packet
The packet handler will read bytes from the serial
communication and construct a packet based off
our defined protocol. Also execute any commands
sent in the packet.
Module
Inputs
Motor Controller
Limit sense GPIO from PSC. Motor axis states for
control signals (see motor_driver struct)
Control signals to the motor drivers.
Sets the control signals to the motor drivers based
on each motor axis current state as defined by the
motor_driver struct. Stop motion and alert CDH
when limits of motors have been reached.
Outputs
Functionality
// Packet struct
typedef struct
{
uint8_t to;
uint8_t from;
uint8_t size;
uint8_t proto_ver;
uint8_t reserved_byte_4;
uint8_t payload[32];
} packet;
// motor_driver struct
typedef struct
{
uint8_t tq1;
uint8_t tq2;
uint8_t dcy1;
uint8_t dcy2;
uint8_t m1;
uint8_t m2;
uint8_t cw_ccw;
//uint8_t clk; //possibly
implemented as a single line to all
motors
uint8_t reset;
uint8_t en;
} motor_driver;

Optoisolators required more current in order to operate with our
desired bandwidth
 XMEGA can’t supply enough current
▪ Added MOSFETs to supply the required current
 Using part: DMN601DMK-7 (dual N-channel MOSFET)

Risks: Motor driver chips are out of stock
 Have just enough for final revision
 Possibly able to get more by end of October
▪ Placed order (backordered, estimated ship date 10/20)
 If not available will need to redesign motor driver controller
▪ Most likely on MDC, only uses 1 motor driver, easier to change
 Alternative motor drivers are available and in consideration
▪ Smaller versions of current motor driver – sufficient for MDC
 In other words there is no more hardware risks
 Software is already partially implemented and works with hardware

Schedule
 Maintaining with schedule
 SMC is ahead of schedule
▪ Original goal: have flashing LEDs (complete)
▪ Current status: stepper motor driving capability tested and
working
▪ Most configuration signals tested
(need to test decay mode)
 Current goal:
▪ establish packet handling (started)
▪ Design motor driver handling firmware
51
Task
Ching
CDH
EPS
Primary
MDC
PSC
Secondary
SMC
Dominic
Frankie
Harout
Secondary
Secondary
Primary
Secondary
Joel
Secondary
Secondary
Secondary
Secondary
Primary
Primary
Secondary
Secondary
Primary
Mechanical
Secondary
Primary
Secondary
User
Interface
Primary
Secondary
Secondary
Primary
Primary
52


CDH
 LCD display
 RS422
 USB
 Ethernet
EPS
 First Sage AC Power and EMI
Filter
 Second stage Rectifier
working (not transformer)



MDC
 Blinking LEDs
PSC
 Timer interrupt driven LEDs
 RS422
 Temperature sensor data sent
to PC
 Limit Sensor (toggle LED)
SMC
 Blinking LEDs
 Driving stepper motors
 RS422
53

Gant chart
54
Item Name
Description
Unit
Price
Quant Total
ity
Amount
STR-MTR-17048
ATSTK600
ATSTK600-TQFP64-2
LM3S6965
ATXMEGA128A1-AU
ATXMEGA64A-AU
MCP9700A-E/To
GP1S53VJ000F
E5 USDIGITAL
LTV-846S
FAN8303
B230A
DN759x
ASV-xxxxxMHZ
TB6560
ADM3071EARZ
DMN601DMK
GBU6J-BPMS
FS7M0880YDTU
ACM9070-701
598-8710-307F
1N400xDICT-ND
WK6249
FOD817A
M9975
ASM69AC
C0816X7R1Cxxxx
ERJ-3GEYxxx4V
161-2306
A35109
Cat5e/ PS2/ DB9/ USB
EE80251S3-0000
EPS/SMC/PSC/MDC
CDH
Stepper Motors
STK 600 development kit
STK600 socket adapter
CORTEX MCU
XMEGA MCU
XMEGA MCU
Temperature Sensors
Photo-interrupt Sensors
Optical Encoders
Optocouplers
DC/DC Converter
Schottky Diodes
Inductors
Oscillator
Stepper Motor Driver
RS422 Driver
N-CH MOSFET
Rectifier bridge
PWM Switching Reg
Common Mode Choke
LED
Rectifier
Fuseholder
High power Optocoupler
High power Inductor
Linear slide
Passive Capacitors
Passive Resistors
Mini-DIN connectors
DB9 Connectors
Cables
Fan
2 Layer PCB
4 Layer PCB
19.00
206.96
102.96
15.29
10.2
8.21
0.34
0.85
62.32
0.73
1.12
0.413
2.73
2.63
4.73
3.4
0.61
1.4
3.64
1.58
2.17
0.31
1.88
0.5
3.47
766.00
0.03
0.03
0.93
0.95
41.53
3.27
3
1
1
2
2
8
5
3
3
25
25
14
5
10
5
10
20
3
4
2
10
8
2
4
3
1
1000
1000
10
4
1
1
33
66
Expense Breakdown
8
2
57
206.96
102.96
30.58
20.40
65.68
1.70
2.55
62.32
18.25
28.00
5.78
23.76
26.30
23.65
34.00
12.32
4.20
14.56
3.16
21.70
10.52
3.76
2
10.41
766.00
30
30
9.3
3.8
41.53
3.27
264
132
Total
2175.522
Subsystem
Total
CDH
246
SMC
273
PSC
251
MDC
250
EPS
200
Mechanical
151
Development Kits
310
Board Order
495
Total
2176
Financial Support
UROP
1000
Halleck Willard
Inc.
826
ECEE Department
367
Total :
2193
55
MILESTONE 1






Blinking (naked eye) LEDs on
SMC, MDC, PSC, CDH
Display functional interboard
communication on RS422
Display one temperature
reading on Realterm through
RS232
Display one limit sensor by
turning off LED when limit
sensor is triggered
Drive one motor via
command from CDH
Ready for Revision B board
orders
MILESTONE2

Display Encoders data via
RS232 or CDH
 Direction
 Position

Display valid C3DP defined
protocols via logic analyzer
for SMC, MDC, PSC, CDH

56
57