Hardware

Amazon best sellers

• Traditional laptop
• Desktop
• Tablet

Amazon Dash button

How to Set Up an Amazon Dash Button

Ultra-budget gaming PC

http://www.maximumpc.com/build-it-little-pc-on-the-prairie/

Computer form factor comparison

• https://en.wikipedia.org/wiki/Computer_form_factor
• Standard ATX > Micro ATX > Mini ITX > Nano ITX > Pico ITX

Mini ITX

• ASRock H97M-ITX/ac
• ASRock B85M-ITX

PC stick

• http://linuxiumcomau.blogspot.com.au/2016/04/ubuntu-1604-iso-for-intel-atom-compute.html
• http://liliputing.com/2015/07/install-ubuntu-14-04-lts-on-the-2gb-intel-compute-stick.html

Possible cons:

1. No Ethernet port
2. Can get very HOT
3. No Audio out jack
4. Does not use opensource chipsets for wifi/bluetooth.

Chipset

What Is a “Chipset”, and Why Should I Care?

Intel Processor

• • Atom: Bay trail, Cherry trail, ...
  • Haswell
  • Broadwell
  • Skylake (sixth-generation Core series of processors) and review
  • Intel's New Core M CPU: Everything You Need to Know
  • Apollo lake replacing Braswell for low-power laptop/netbook/cloudbook.
  • http://www.fanlesstech.com/

SoC

My own collection of SoC

Device	Family	Instruction	Clock & Memory
Pogoplug	ARM9	ARMv5	1.2GHz, 256MB
Raspberry Pi	ARM11	ARMv6	700MHz, 512MB
Beaglebone Black	Cortex A8	ARMv7	1GHz, 512MB
UDOO	Cortex A9	ARMv7	1GHz, 1GB
Odroid Xu4	A15 & A7	ARMv7	2GHz & 1.4GHz, 2GB

See wikipedia for a list of ARM cores. These SoC are 32-bit. The newest ARM architecture is ARMv8 which is 64-bit; see here.

Arduino Yun vs BBB vs Intel Galileo vs Raspberry Pi

from Adafruit. It includes spec comparison, performance test, power usage, ...

• Arduino motor spin
• Arduino Uno vs Beaglebone vs Raspberry Pi from Makezine.com.
• Arduino Uno vs Raspberry Pi vs Beaglebone black from lifehacker.com.

Low end PC/tablet

Lenovo IdeaTab Lynx K3011

Intel® Atom™ Z2760, 2G ram, 64GB storage and Micro-HDMI.

HP Chromebox Desktop

Intel Celeron 2955U Processor 1.4 GHz, 2GB DDR3 RAM, 16GB ssd

ASUS Chromebox M075U

1.7 GHz Intel Core i3-4010U Processor, 4GB of 1600 MHz DDR3 RAM, 16GB Solid State Drive

A newer one is CN62.

HP Stream 8

Intel® Atom™ Z3735G Quad Core (64-bit), 1G ram, 32GB storage. The C: drive shows the space is 23.5 GB. The free space is 20GB. After the first Windows update the storage space is reduced from 18.6 to 16.8. After running Disk cleanup utility, the storage now becomes 17.1 (still lose a lot). So the lesson is not to run Windows update if the disk space is very limited (eg tablet) & everything is working fine now.

ECS Liva

• http://www.anandtech.com/show/9554/ecs-liva-x2-review-a-compact-fanless-braswell-pc
• X2 using Intel® Braswell N3050 SOC
• X using Intel® Bay Trail-M/Bay Trail-I SOC (N2808). For?reason, it won't be shipped to my area from newegg.

Samsung pico DLP projector sp-h03

LED, 30 ANSI lumen 854x480, 12V & 1A power. The manual is available at Samsung web site here. The input signal in D-Sub can be 1280x800, 1280x768, 1280x720 resolution although the manual also said "All resolutions higher or lower than 854 x 480 are converted to 854 x 480 by the scaler chip in the projector. To obtain an optimal picture, the resolution from the PC should be similar to the projector (854 x 480)".

Vivitek Qumi Q5 500

Lumen WXGA HD 720p 3D-Ready Pocket DLP (buydig.com, vivitekusa.com)

UFS, eMMC, SSD

• http://www.androidauthority.com/what-is-ufs-and-why-it-matters-590015/
• http://www.howtogeek.com/293339/what-makes-emmc-flash-memory-viable-in-mobile-devices-but-not-pcs/ eMMC vs SSD. eMMC (NVRAM technology) has a write cycle of 3k to 10k but SSD (NAND or NOR technology) has a write cycle of 10k to 30k.

MicroSD card speed comparison

http://www.midwesternmac.com/blogs/jeff-geerling/raspberry-pi-microsd-card

USB device speed comparison

See http://www.elinux.org/RPi_SD_cards#Performance for an objective way to get write/read speed by using command line tool 'dd'.

Device	Read	Write	FS
MicroCenter4G	Example	12.77MB/s	Ext3
MicroCenter4G	Example	5MB/s	vfat
Patriot XT 32G USB3.0	Example	50MB/s	vfat
Patriot XT 32G USB3.0	Example	115MB/s	fat16
Patriot XT 32G USB3.0	Example	113MB/s	fat32
Patriot XT 32G USB3.0	Example	24MB/s	ntfs
Patriot XT 32G USB3.0	Example	139MB/s	ext2
Patriot XT 32G USB3.0	Example	50~100MB/s	ext3
Patriot XT 32G USB3.0	Example	140MB/s	ext4
Example	Example	Example	vfat

When testing Patriot XT USB 3.0 drive, I partition it into ext2 (15GB)& ext3(15GB). The problem of unstability in Patriot XT's ext3 partition is not related to ext3 partition because if I switch the order of partitions of ext2 and ext3, then ext2 becomes unstable.

• A word about USB flash drive.
  • According to the Slo Bytes USB Flash Drives report from Brian K. Lewis, flash drives are capable of handling 10 thousand to 10 million write and erase operations during their lifetime, depending on the source as well as the specific USB drive. Regardless, a flash drive typically will outlast any standard hard drive. The main concerns about the life expectancy of a flash drive are damage from neglect and becoming lost or stolen.
  • The life expectancy of a USB Flash Drive can be measured by the number of write or erase cycles. USB flash drives can withstand between 10,000 to 100,000 write/erase cycles, depending on the memory technology used. When the limit is reached, some portion of the memory may not function properly, leading to lost of data and corruption.
  • Most experts would agree that around 10 years is about what you can expect to retain data on a flash drive without powering it up. That means you can lock away a USB drive for 10 years and return to still see your data. After 10 years of not being powered on, the electrical charges determining if bit of information is either a ‘1’ or a ‘0’ gets hazy. This is because like all electrically charged devices, they suffer from what is called electro/magnetic deterioration; or simply put, where devices will eventually lose their power.

• The copy-paste speed on my 7200rpm hard disk is about 160MB/s.
• Tested using Seagate portable drive SRD0SP0 500GB with USM((Universal Storage Module)/USB 3.0. When it is connected to USB 2.0/3.0, the writing (from an internal hd onto it) speed is at best 30MB/s. When it is connected to USB 3.0, the writing (from it to an internal hd) speed is at least 60MB/s.
• DIY USB on the go cables.

Hard drive comparison

The Most Reliable Hard Drive Models

ATX 24pin power supply

and this. A simple test from wikihow.com.

PCIe SSD

http://www.howtogeek.com/238253/what-is-a-pcie-ssd-and-do-you-need-one/

How to silence your computer mouse

An easy way to take off the cape of the rectangle box is to use a pairs of long nose pliers instead of a knife. The method works on my Logitech M210 mouse. The trick is to shorten the click distance.

Cellular phone frequency list

North America & Worldwide. In particular, T-mobile uses 1700 (3G UMTS), 1900 (3.5G HSPA+), 2/4/12 (4G LTE) and Chunghwa telecom uses 2100 for 3G/3.5G.

What is the difference between G, E, 3G, H, H+ and 4G symbols? We find out!. The order is (from fastest to slowest)

1. 4G
2. H+
3. H
4. 3G
5. E
6. G
7. 2G

ZenFone 2

from ASUS.

Vehicle camera recorder

1. night vision 2. can turn on/off manually 3. pictures stable (not flicker) 4. G-sensor 5. 3D turning on mount racket 6. no surprising things like auto turned off, (power, start) buttons not working, freeze 7. video space (640x480 takes 100MB for 1 min???). The Amazon website has a list of popular dash cams.

Amazon Fire TV

• Navigation with the remote.
• Install XBMC/Kodi

Live TV

• How to Watch Live TV on Your Apple TV

Kill A Watt P3

Note: click the 3rd button to switch between Watt and VA; similarly for the 4th and 5th button.

Volt --- Amp --- Watt/VA --- Hz/PF --- kWH/Hour

The relation of Volt-Amp-Watt-VA-PF are

1. VA = Volts x Amps
2. Watt =  VA x Power factor  (OR W = VA x PF)

For example, if the apparent power is 3000 VA and the power factor is 0.8, the real power is 3000x0.8=2400 Watt.

From the Pepco company, my bill is $530.40 (total usage is 4097 KWh) from 11/27/2014 to 12/16/2014.

Delivery Charges:
=================
Distribution services:
Customer charge:                           = 7.39
Energy charge, first 800 KWH x 0.0272      = 21.76
Energe Charge, next 3297 Kwh x 0.0272       = 89.71
Franchise tax (delivery) at .00062 per kWH = 2.54
Universal service charge                     0.36
MD Environmental surchage .00015 per kWH   = 0.61
EmPower MD charge res .0037 per kWh        = 15.16
Gross Receipts tax  2.0408%                = 2.81
Montgomery city energy tax res .01131 per kWH = 46.34
Administrativ credit res .0002912 per kWH  = 1.19-
==========================================================
Subtotal                                      = 185.74 

Supply charges:
===============
Generation services:
  Energy Charge  4097 kwh x 0.07732          = 316.78
  Procumental cost adj res .0005936 per kwh  = 2.43-
Transmission services:
  Energy charge  4097 kwh x .007250         = 29.70
 gross receipts tax at 2.0408%               = 0.61
==========================================================
Subtotal                                     = 344.66
Total                                        = 530.40

So it looks like the charge per kWH is about .0272 + .0037 + .01131 + .07732 + .00725 = 0.12678.

On my home server (idle most of time) with a cpu of AMD Phenom(tm) II X6 1055T Processor, it consumes 1.75kWh in 24 hours. Instantly Kill-a-watt shows 70+ Watt from the machine which makes sense (24 * 70 ~ 1750). So the yearly cost of leaving the machine on is about 1.75 * 365 * 0.12678 = 81.

For Pi-top (Raspberry Pi 3), 11 hours is 0.06 kWh. 0.07 amp. 0.59 PF. 9 VA and 5 Watt (120v * 0.07amp * .59PF = 9VA * .59PF). For 24 hours, it consumes ~0.14kWh (vs 1.75 kWh in Phenom).

See http://www.howtogeek.com/234222/why-you-never-need-to-put-your-apple-tv-or-other-modern-devices-to-sleep/ for explanation about Apple TV and Fire TV case. For example, 2.1 watts of power /1000 * 24 * 365 * $0.125 = $2.29 per year.

UDOO 4W, SainSmart 9" LCD 3W.

Laser Engraving Machine

• NEJE 300mW Mini DIY Laser Engraving Machine Picture Logo CNC Laser Printer and 500mW version.
• mdrawBot and 500mW laser engraver
• Laser cube 2.0 (100mw laser diodes). Laser engraver from makeblock.cc (500mw laser engraver).

Make your own laptop screen for Raspberry Pi

See raspi.tv

E-ink monitor

Paperlike monitor - Windows is supported. For other OS, uses VirtualBox.

Kindle DX as an external monitor

• http://www.pcworld.com/article/259582/how_to_use_a_kindle_dx_as_a_pc_display.html
• https://tinyapps.org/docs/e-ink-monitor.html

Kobo ereader

I have a Kobo Aura HD. The touch screen is controlled by infrared (like the Nook Simple Touch, no requiring electrical conductivity), not capacitive or resistive technologies. Even a paper or an eraser works on the touch screen. Its screen is 6.8 inch, 1440 x 1080-pixel display with 265 dpi. The brightness is 326 lux. The built-in front light comes the light technology from the ComfortLight. It directs light at the page and boasts an even distribution across the display. The microSD slot can add up to 32GB to the built-in 4GB of storage. The exact model is not on sale now because it is replaced by H2O.

Firmware download

• http://www.mobileread.com/forums/showthread.php?t=185660

Kobo Wifi Weather Forecast

http://www.mobileread.com/forums/showthread.php?t=194376

KOReader

The pdf program is not quite useful for scientific papers.

Alternatively, we can try KOReader. Currently my Kobo FW is 3.18.0 (9/23/2015). I am following the procedures on KOReader's Kobo devices page.

1. Go to here and download <KBStartMenu_07inclUp4.zip>. Extract the folder kbmenupngs (it contains png files) and put it to the root folder of Kobo. Also put KoboRoot.tgz to .kobo hidden directory (putting it onto .adds won't work). Reject and reboot.
2. Download <koreader-kobo-arm-linux-gnueabihf-v2014.04> from v2014.04-stable github page. Put koreader folder in the .kobo hidden directory. Ignore the png file and KoboRoot.tgz file there. Reject and reboot.

If something goes wrong, we can go to Settings -> Device information -> Factory reset to reset the system. It can also download the update after the wifi configuration is set up.

When you update koreader, it should be sufficient to extract the koreader folder, without KoboRoot.tgz - that one is needed to add the launcher.

Standby does not work out of box. See http://www.mobileread.com/forums/showthread.php?t=216960&page=85. That is, run

nano -c /media/brb/KOBOeReader/.kobo/koreader/frontend/ui/uimanager.lua

and change the Standby value from 1 to 4 and suspend function call from 0.5 to 2. The standby problem is resolved.

Battery always 100% (too good to be true, I have not used the ereader for a while). http://www.mobileread.com/forums/showthread.php?t=220912. It`ll take care of itself after a few charge cycles.

.kobo folder after reset

After I run factory reset on the device (and plug in it to my computer), I see the device only has 3 hidden directories

brb@brb-P45T-A:~$ ls -la /media/brb/KOBOeReader/
total 20
drwx------  5 brb brb  4096 Dec 31  1969 .
drwxr-x---+ 4 brb root 4096 Oct 11 10:22 ..
drwx------  2 brb brb  4096 Oct 11  2015 .adobe-digital-editions
drwx------  7 brb brb  4096 Oct 11  2015 .kobo
drwx------  8 brb brb  4096 Oct 11  2015 .kobo-images
brb@brb-P45T-A:~$ ls -la /media/brb/KOBOeReader/.kobo
total 152
drwx------ 7 brb brb   4096 Oct 11  2015 .
drwx------ 5 brb brb   4096 Dec 31  1969 ..
-rw-r--r-- 1 brb brb     25 Oct 11  2015 affiliate.conf
drwx------ 2 brb brb   4096 Oct 11  2015 certificates
-rw-r--r-- 1 brb brb     76 Oct 11  2015 device.salt.conf
drwx------ 2 brb brb   4096 Oct 11  2015 dict
drwx------ 2 brb brb   4096 Oct 11  2015 kepub
drwx------ 2 brb brb   4096 Oct 11  2015 Kobo
-rw-r--r-- 1 brb brb 110592 Oct 11  2015 KoboReader.sqlite
drwx------ 6 brb brb   4096 Feb 28  2013 slideshow
-rw-r--r-- 1 brb brb   3298 Oct 11  2015 Trolltech.conf
-rw-r--r-- 1 brb brb     84 Oct 11  2015 version
brb@brb-P45T-A:~$ ls -la /media/brb/KOBOeReader/.kobo-images/
total 32
drwx------ 8 brb brb 4096 Oct 11  2015 .
drwx------ 5 brb brb 4096 Dec 31  1969 ..
drwx------ 3 brb brb 4096 Oct 11  2015 132
drwx------ 3 brb brb 4096 Oct 11  2015 18
drwx------ 3 brb brb 4096 Oct 11  2015 213
drwx------ 3 brb brb 4096 Oct 11  2015 233
drwx------ 3 brb brb 4096 Oct 11  2015 66
drwx------ 3 brb brb 4096 Oct 11  2015 70

Dictionaries

KOReader supports any Stardict format dictionaries. To use that, we need to download and put the dictionary 'folder' in the right place (.kobo/koreader/data/dict) of the Kobo ereader.

I tried two dictionaries (Longman Dictionary of Contemporary English and cdict-big5 dictionary) from http://abloz.com/huzheng/stardict-dic/. And they work fine.

Turn your Kobo into a Debian Linux tablet

http://www.mobileread.com/forums/showthread.php?t=222123

Flexible E-ink

http://liliputing.com/2015/10/wove-band-smartwatch-has-flexible-e-ink-touch-display.html

Power over Ethernet (PoE)

• https://en.wikipedia.org/wiki/Power_over_Ethernet
• TP-LINK TL-POE10R Gigabit PoE Injector or Splitter
• p56 of https://www.raspberrypi.org/magpi-issues/MagPi45.pdf

Some devices powered by PoE include VoIP phone, IP camera, wireless access point. router.

Trendent USB to ethernet adapter

ASIX AX88772A. The windows driver can be found on axix.com.tw. The one from Trendent website does not work.

How to park your car on a hill

https://www.reddit.com/r/lifehacks/comments/1c6jfb/when_parking_your_car_on_a_hill_put_the_car_in/

When parking your car on a hill, put the car in neutral, set the emergency brake, then put the car in park (or in gear). This puts the weight of the car on the emergency brake rather than the transmission and can extend the life of your transmission.

3D Print

• 3D printer shines in prototyping and home production markets.
• Tow types of printing process: Fused Deposition Modelling (FDM) and Stereolithography (SLA). Approximate cost per 1kg of material is $25 for FDM and $100 for SLA. PLA is a biodegradable plastic derived from renewable resources, such as sugarcane or corn starch. PLA is prone to clogging. ABS is derived from fossil fuels and is not biodegradable; printing with it can give off a strong burning plastic smell.
• Two types of coordinate system: Cartesian (they have x-, y- and z-axis) and Delta (suspend the extruder from three arms in a triangle arrangement; these machines were designed to print parts fast! ).
• 5 Ways to Master 3D Printing
• Ultimate Beginner’s Guide to 3D Printing
• http://3dprintingforbeginners.com/
• RepRap is a open source 3D printer prototyper. See the Wikipedia page.
• OctoPi a Raspberry Pi distribution written for 3d printing.
• http://www.thingiverse.com/
• Over 100 3D Printing Projects for Your Home
• How to Hollow Out 3D Models to Save Material and Time

Printer

• Original Prusa i3 MK2 kit
• Acrylic 3DCSTAR P802-MHS 3D Printer
• To create a successful 3d print
  • The first layer is the most importnat
  • To have a wonderful first layer, the levelling is the key
  • To have a good levelling, make sure the fraction is reasonable
  • Simple architecture is easy to create; models with hollows too close to each other are easy to fail

JGAurora A3

JGAurora A3 and Amazon. It is based on Prusa i3.

• Both cura and Repetier-Host (slicer) software ! it depends on different models ,each software has its advantages!
• it have heated bed. max temp at security for this machine :90-100'degree of hotbed.
• The controller has an arduino mega embedded in the controller board so you can flash the latest Marlin firmware.
• The nozzle is MK8 extruder 0.4mm nozzle diameter,1.75mm filament diameter,you can use M6 nozzle!
• there is no auto leveling for this kit. layer thickness: 0.1-0.4mm .resolution 0.1mm.
• This printer kit only works with plastic filament not conductive filament.
• max printing size of this machine: 200*200*180mm.
• Cables assembly video.
• 1 layer height: normal quality prints are 0.1mm,high quality is 0.06mm.
• The extruder looks like MK8
• On Cura setting: 280 (width)x220(depth)x180(height), 0.4 nozzle size, heated bed. Profile -> Import -> configure.ini file. But my experience shows it is best to use 270(X) x 250(Y) x 180(Z). If we use the real size for the X and Y plane (200x200) for the printer, the center of the print will be too close to (0,0).

     back
  +--------+
  |        |
  |        |
  |        |
  +--------+
(0,0)
     front

Printing tips/troubleshooting

• Troubleshooting Guide to 23 Common 3D Printing Problems
• Monoprice Select Mini 3D Printer: 7 Essential Tips for Better Prints
  • Slow it Down: using 1x speed for large objects — or .5x speed for small or high-quality objects.
  • Use an Alternative Print Surface:
  • Maintain the Extruder Nozzle: remove the nozzle and soak it in acetone for several days. A clogged nozzle will result in the printer making a “thump” noise every fifteen seconds, and the filament will come out at a lesser flow. You can tell if you have a clog by extruding filament from the move menu while heated up. If it curls, you have a clog.
  • Retraction: change the retraction distance to 4mm and the minimum distance over a non-printed area to begin retraction .5 mm.
  • Use the Correct Temperature: 200 for PLA. Anything higher, and you’ll run into stringing. Lower, and the nozzle will clog.
  • Change Layer Height: don’t try to print anything with layer height above .15 mm
  • Store Your Filament Like a Pro.

How to prevent nozzle clogging

• https://www.3dhubs.com/talk/thread/preventing-and-fixing-jams-tips-tricks
• http://3dprinting.stackexchange.com/questions/214/how-do-i-keep-my-extruder-head-from-getting-clogged
• Troubleshooting Guide to 23 Common 3D Printing Problems
• Stop 3D printer filament jams with this simple trick!
• Universal Filament Filter and Lubricator
• Post printing maintenance
• How to remove filament. Heat the nozzle. When we push out some filament, we immediate pull the filament. It works :)))

Bed temperature

According to this

• PLA: 50-60°C
• ABS: 100-110°C

And this website recommends

• Bed: 70 (first layer), 60 (other layesr)
• Extruder: 195 (first layer), 185 (other layers)

Under-Extrusion

Printer cannot supply the material needed

• Check the filament diameter
• Check the head
• Set the extrusion multiplier

Over-Extrusion

Too thick layers

Gaps between Infill and Outer Wall

• Check the infill overlap. In Cura by default this is set to 15% so raise it to 30%.
• Printing infill before the perimeter. In Cura check to see if you have ‘Infill prints after perimeters’ ticked.

Misaligned Layers

• Check belt tension
• Are top and bottom belts the same?
• Tighten the belt tensioner.

3D modeling software

• How to Design Things to 3D Print With Open Source Software

Tinkercad

Online

Sketchup

Some people comment Sketchup is really lousy for anything more complicated than a cube.

Need to download the sketup-stl extension to export STL files.

Blender

• Crashes when I select an object. The solution is to use blender-softwaregl instead of blender program. See this post.
• Manual
• Keyboard shortcuts
  • Delete a scene: x
  • Delete an object: object mode -> x
  • Save a scene: Ctrl + s
  • Add: Shift + a
  • Property of an object (eg change dimensions/size): n
  • Move: g
  • Cylinder: after adding a cylinder, press f6 to change its properties (vertices, radius, depth)
  • Orthographic view: 5 (Numpad)
  • Front view: 1 (Numpad)
  • Zoom in: . (Numpad)
  • edit mode: Tab
  • Select an object: File -> User Preferences -> Select with (Left|Right) mouse button
  • Undo: ctrl + z
• Navigation
  • Mouse wheel only: Zooms in and out of the scene
  • Shift + mouse wheel: Pans up and down
  • Ctrl + mouse wheel: Pans side to side
  • Shift + Alt + mouse wheel: Rotates up and down
  • Ctrl + Alt + mouse wheel: Rotates side to side
  • Change angle: NUM key. Ctrl + NUM key.
  • Blender only renders what a camera sees. You can find out what the camera is seeing by pressing the 0 key on the NumPad.
  • F12 key to render the scene so you can see it. Esc key to close the rendering window.
  • F11 key to see the previously rendered view. Esc key again.
• To place an object on the floor
• 3D view window. There are three objects in the default scene. The first is the default cube.
  • The cube you see is a 3D mesh in the shape of a cube; you can use it or delete it.
  • The four-sided cone with a triangle above it is the camera.
  • The black dot surrounded by dotted lines with a line hanging down from it is a lamp.
  • When Blender is opened, the cube is the active object, which means that it is the object currently being worked on.
• 3D Tools
  • At the origin, the center of the world in Blender, there are two controls—one is the 3D Cursor. It's a red and white dashed circle with four black lines through it, and it is shown in the center of the following screenshot. This marks the location of where a new object will be made. It can be moved wherever you need it, as you'll discover later.
  • The other 3D control at the origin is the 3D manipulator, which is on the right-hand side in the following screenshot. It's a white circle with red, green, and blue arrows coming out of it and an orange dot in the center. It gives you control of rotating, translating, and scaling the active object in 3D.
• There are twelve basic types of objects: Armature, Camera, Curve, Empty, Force field, Lamp, Lattice, Metaball, Mesh, Surface, Speaker, Text.
• Measure 3D

       +z
      |
      | / +y
      |/ 
-x ---+--- +x
     /|
    / |
-y /  | -z

• Perspective and Orthographic views
  • In Perspective, all parallel lines stretch off to the horizon and finally appear to meet at a single point. This is pretty much what our eyes see.
  • Orthographic is slightly different. It comes from the world of Computer Aided Drafting (CAD). With Orthographic projection, all parallel lines are shown as being parallel
• Books
  • Blender 3D Basics Beginner's Guide Second Edition By Gordon Fisher
  • Blender 3D By Example By Romain Caudron, Pierre-Armand Nicq
  • Blender 3D Architecture, Buildings, and Scenery By Allan Brito

OpenSCAD

You can design models using code.

Others

• Google Sketchup
• TinkerCad
• Windows 10 3D Paint and 3D Builder
• FreeCAD (available for the Pi2 and above)
• OnShape - a freemium cloud-based CAD software
• Meshlab: sudo apt-get install meshlab
• http://www.viewstl.com/ Online viewer

Slicing software

• 20 Free STL File Viewers (Online, Mac, PC, Linux, Android, iOS)
• List of Best 3D Printing Software
• http://reprap.org/wiki/Useful_Software_Packages List of software
• r2stl R package

Free STL files

https://all3dp.com/best-sites-free-stl-files-3d-printing/

3D print pen

SUNLU $44. Filament: ABS PLA. Filament diameter: 1.75mm.

Roku

• 5ik.tv

Router and QoS

http://www.howtogeek.com/75660/the-beginners-guide-to-qos-on-your-router/

• Prioritize by Service
• Prioritize by Interface
• Prioritize by Device with IP Addresses
• Prioritize by Device with MAC Addresses

Wifi and health

• http://www.howtogeek.com/234817/dont-worry-wi-fi-isnt-dangerous/

Logitech Unifying Software

Logitech wireless solar keyboard k750

• Best typing feeling (similar to a laptop computer).
• http://www.logitech.com/en-us/product/k750-keyboard
• Support
• Solar App and download links for Windows & Mac.

One problem is there is no Num Lock and Caps indicator on the keyboard unless you have install Logitech SetPoint software (Windows & ChromeOS).

Qmote

A bluetooth based gadget to control a windows/android/ios device. See http://qblinks.com/support

How to Replace an Outlet That’s Controlled by a Light Switch

http://www.howtogeek.com/281023/how-to-replace-an-outlet-thats-controlled-by-a-light-switch/

How to Ship Packages Without Leaving Your House

http://www.howtogeek.com/284060/how-to-ship-packages-without-leaving-your-house/