Handcraft google cardboard. Make laser cutter from blueprint.

1. Making
Google Cardboard &
Laser Cutter
Eiichiro Iwata
2016年12月15日
PFxセミナー

2. Self Introduction
• Name
• Eiichiro Iwata (@eiichiroi)
• Profile
• M.E in Computer Science – Saitama University 2008 - 2010
• ICPC World Finals 2009
• Preferred Infrastructure, Inc. 2010 - 2016/10
• Developed Search Engine “Sedue”
• Developed Analysis Platform for BigData “Sedue for BigData”
• Retrieva, Inc. 2016/11 - present
• Developing Q&A search solution ”Answer Finder”
• Fobby
• Brewing coffee (mame club)
• Playing games (Spaltoon, Catan, Syogi, …)
• Making (electronic) devices (Today’s topic)
2

3. Table of Contents
• Making
• Google Cardboard
• Laser Cutter
3

4. What’s Google Cardboard? (1/4)
4
https://vr.google.com/intl/en_us/cardboard/

5. What’s Google Cardboard? (2/4)
• Google VR
• “Virtual reality for everyone”
• = SmartPhone + Headset(Cardboard/Daydream)
5
Google Cardboard Daydream 3rd party
https://vr.google.com/intl/en_us/cardboard/
https://vr.google.com/daydream/

6. What’s Google Cardboard? (3/4)
6
Headset Price Supported
Phone
Memo Date
Google
Cardboard
(3rd party)
cardboard $10〜20 >= Android 4.1
Low-cost for trial.
Hold it by hands. 2014/06
Daydream fabric $79 Pixel
Moto Z
High-end and Comfortable.
With wireless controller.
2016/11

7. What’s Google Cardboard? (3/4)
• Apps
• Cardboard (Official demo apps)
• Google Earth (you can fly around in Google Earth)
• YouTube VR (watch videos with VR-mode or 360-degree video)
• …
• Cardboard Camera
• you can take 3D photo, enjoy it with Cardboard App
• etc
• SDK
• for Andriod / iOS / Unity / Unreal Engine
7

8. Headset’s specification is public.
8
https://vr.google.com/intl/en_us/cardboard/get-cardboard/

9. Made it by hands.
9print out sheets and cut it on cardboards by cutter knife

10. Made it by hands and hands.
10Bought lenses at 100 shop
Completion!
(but focus distance is not fit…)
Fold them

11. Impressions for Google Cardboard
• fun and interesting
• focus distance of lenses is very important
• precisions to cut cardboards by hands is less…
• I want to cut cardboards with high precision.
• Let’s make laser cutter and cut cardboard by it.
• Supplement:
• It is distributed at Google I/O 2014 (2014/06)
• I Maked at 2014/07.
• Now, we can buy kits easily. it is recommended.
11

12. What’s Laser Cutter?
• Machine tools that use a laser to cut materials
• CNC (Computer Numerical Control) is popular
• Materials
• papers
• wood board
• acrylic board
• …
• (〜3mm)
• Note:
• Need more power(powerful laser cutter) if the material
is thick or hard. It also have focus distance problem.
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CAD/CAM
(AutoCAD, Illustrator, …)
Laser Cutter
Drawing
(DXF, SVG, CDR format)
GCode
convert
create & save
load & execute

13. 3-ways to use laser cutter
• Rent at shops (Recommended)
• Need only data files and materials
• FabCafe Tokyo (at Shibuya)
• DMM.make AKIBA
• Buy Laser Cutter Kit & Make it
• laserbot (makeblock)
• Mr. Beam (Kickstarter project)
• Smart Laser Kit Mini (SmartDIY)
• Design & Make myself (Not recommended)
• Refer open source blueprint (Smart Laser Kit Mini)
13
easy
hard
Laser Cutter(1.6W)
CO2 Laser Cutter(60W)
Powerful!
https://akiba.dmm-make.com/about/machinesDetail/32
http://www.makeblock.com/laserBot-robot-kit

14. Smart Laser Kit Mini (Official demo)
14
• See following url
• https://vimeo.com/135843224

15. Components
15
Laser Module
X-Drivng Module
Y-Drivng Module Y-Drivng ModuleController

16. Principles of Laser Cutter
• X-Axis move (Y-Axis move)
• Power source is torque of stepper motor
• Timing belt convert from torque to linear momentum
• Carriage move along the axis
• Limit switch is origin(0). It is also called home position
16
Carriage
Stepper Motor
with pulley
Idler
Timing Belt
Limit switch
Axis

17. Principles of Laser Cutter
• Laser Diode
• emit light and focus specific wavelength by lenses
• its power depend on wavelength and current
• elements determine wavelength(fixed)
• drived by constant-current circuit
17
short & strong long & weaklaser cutter
(445nm, 2W)
DVD-R/RW drives
(780nm, 400mW)

18. Principles of Laser Cutter
• Laser Diode
• its power depend on wavelength and current
• elements determine wavelength(fixed)
• drived by constant-current circuit
• more current, more power!
• note:
• Need heat sink & fan
• Need glasses to save eyes
• CO2 laser is different from laser diode
18
http://cms.diodenring.de/electronic/microcontroller/111-blue-laser-diodes

19. (Electrical) Architecture
19
GRBL
GRBL
Controller
Arduino Uno
Laser Module XY-Driving Module
software
hardware
USB
(Serial)
PC
communicate
Host Microcomputer
Driver Circuit
Laser Diode
CNC Shield
X-Motor
Driver
Stepper
Motor
Y-Motor
Driver
Stepper
Motor
Y-Motor
Driver
Stepper
Motor

20. X-Driving Module
• X-Driving Module
• Arduino CNC Shield
• Stepper motor with driver chip(pololu drv8825)
• X-Limit switch(to detect origin)
20

21. Y-Driving Module
• Y-Driving Module are almost equal to two X-Driving
modules
• Two motors move in the same way
• direction of rotation is reversed because of attaching
direction
21

22. (Electrical) Architecture
22
GRBL
GRBL
Controller
Arduino Uno
Laser Module XY-Driving Module
software
hardware
USB
(Serial)
PC
communicate
Host Micro Controller
Driver Circuit
Laser Diode
CNC Shield
X-Motor
Driver
Stepper
Motor
Y-Motor
Driver
Stepper
Motor
Y-Motor
Driver
Stepper
Motor

23. GRBL / GRBL Controller
• GRBL
• embedded CNC controller run on Arduino
• open source
• Receive commands(GCode) via USB(Serial port)
• Control arduino and its I/O (laser and stepper motors)
• GRBL Controller
• software(communicate with GRBL) run on PC
• open source
• Load and Send commands(GCode) via USB(Serial port)
23

24. GRBL’s parameters calc from parts
• stepper motors spec
• ratation degree: 1.8 [degree/step]
• number of steps per 1 ratation: 200 [step/ratation]
• pulley spec
• number of teeth: 20 [teeth/ratation]
• pitch: 2 [mm/teeth]
• -> 2 * 20 = 40 [mm/rotation]
• number of steps per 1mm (with 1/32 step mode)
• 200 / (1/32) / 40 = 160 [step/mm]
• Minimum moving unit
24

25. GCode
• Numerical Control Programming Language
• used for CNC (laser cutter, 3D printer, milling machine…)
• GRBL accepts GCode
• Command types
• Config
• Area(max X, max Y)
• Min moving unit, max speed, max acceleration
• Move
• Straight
• Arc
• Spline
• …
• Other control
• Laser/Fan switches
25

26. GCode Examples
(Header begin)
G90 (Set absolute distance mode.)
G21 (Use millimeters for length units.)
F100.000000 (Set feed rate.)
(Header end)
M08 (Set coolant on.)
G1 X0.000000 Y0.000002 (Move linearly to the point)
M03 (Set spindle on.)
G1 X1.790347 Y0.829030
G1 X1.252361 Y1.058336
G1 X3.183819 Y2.989780
… 26
Configuration in header

27. (Electrical) Architecture
27
GRBL
GRBL
Controller
Arduino Uno
Laser Module XY-Driving Module
software
hardware
USB
(Serial)
PC
communicate
Host Micro Controller
Driver Circuit
Laser Diode
CNC Shield
X-Motor
Driver
Stepper
Motor
Y-Motor
Driver
Stepper
Motor
Y-Motor
Driver
Stepper
Motor

28. Testing as Pen Plotter
• Use pen instead of Laser Module
• Test XY-Driving module & GRBL
• Test data is desert tile of Catan (board game)
• various designs for 3D printers, laser cutters, milling machines
are shared in thingiverse.com
• DXF format
• Wrote DXF2GCode converter
• GRBL don’t support spline curves
• spline curve can be approximated by lines
• Load DXF & output approximated shapes
28
example of b-spline curve

29. Testing as Pen Plotter: Result
29
DXF Format (ideal)
There are many wasteful moves(paths)!
(Note: pen is always on the paper)
Result (real)

30. GCode Path Optimizer
• To find best GCode path is equal to solve a traveling
salesman problem(TSP)
• must visit all shapes
• implement greedy algorithm
• select nearest shape from current shape
• approximate solution
• complexity is O(V2): V is number of shapes
30

31. GCode Path Optimizer: Result
31
before after
Good enough!

32. (Electrical) Architecture
32
GRBL
GRBL
Controller
Arduino Uno
Laser Module XY-Driving Module
software
hardware
USB
(Serial)
PC
communicate
Host Micro Controller
Driver Circuit
Laser Diode
CNC Shield
X-Motor
Driver
Stepper
Motor
Y-Motor
Driver
Stepper
Motor
Y-Motor
Driver
Stepper
Motor

33. Laser Module
• Made from scratch
• because this module is not public at that time
• Main parts
• Laser diode (〜2W)
• Constant-current circuit
• Constant-current circuit
• LM317
• can generate constant-current
• Darlington transistor
• need to drive high current from microcomputer
• two transistor are combined to large one
33
write circuit diagram by hands.
darlington

34. Testing as Laser Cutter: paper
• materials
• paper(0.087mm, white)
• feed rate 600 [mm/min]: good
• feed rate 800 [mm/min]: almost cut
• feed rate 1000 [mm/min]: don’t cut well
• drawing paper(0.4mm, black)
• feed rate 100 [mm/min]: slightly burned
• feed rate 150 [mm/min]: good
• feed rate 300 [mm/min]: good for engraved mark
• thick and color of material is important
• best feed rate is different
34

35. Testing as Laser Cutter: cardboard
35
feed rate is too slow,
slightly burned
feed rate is good,
but it’s not cut completely
multiple trials
In more thick materials, it is important to repeat.
focus is off…?

36. Other problems in making
• it is difficult to find various parts myself
• Aluminum frame size, screw/nuts size, high power diode
• short laser driver circuit & broke laser diode
• diode is very sensitive
• retried with new parts…
• broke balsa plates because I rotate Y-Axis motors in
reverse directions
• need to add emergency stop button…
• many parameters per materials
• feed rate, height of laser(focus distance), …
36

37. Parts shops
• Monotaro
• aluminum frames
• bearing
• eBay (Ali Express)
• Laser Diode
• Home improvement center (ex. DOIT, Tokyu Hands)
• Screw & Nuts
• Wooden plates (balsa plates)
• Akizuki Denshi / Sengoku Denshi at AKIHABARA
• Electric parts (board, connectors, wire, transistors …)
37
EC site

38. Conclusion
• Making Google Cardboard
• Let’s buy kits and fun!
• Making Laser Cutter
• Fun & Interesting
• Several problems happen in real world
• I have not created google cardboard by laser cutter yet
• Not recommended. Rent it at shops!
38