How do you do Oculus Rift roomscale the easy way?

Bypass the USB-A low power delivery of your motherboard and use a USB-C hub like THIS ONE

This tiny box muxes 4 x USB3.0 signals into a USB-C signal which in the case of this z370 motherboard leads to collision free communication and also pushes usb-C higher power to all 4 usb-A ports.
The result is tracking and audio with no glitch.

Mansplaining (maybe): Each sensor eats up 76 MB/s and in USB 2.0 mode 16 MB/s, goggle audio probably eats up 48 kHz@16bits X 2 = much less than 1 MB/s total with 2 sensors: <160 180="" 3="" and="" mb="" p="" s="" sensors="" with="">Why does this collide on the z370 internal USB controller but not via a usb-C hub? My guess is power supply of the hub via usb-c increased power delivery makes the end point's electronic more stable so the signal timing is more stable, less for the z370 controller to correct, no loss tracking.
It might be why a powered USB-A will also provide stable tracking. In other word it's not the bandwidth as much as enough power to the sensors.

TurboTax - expensive bugs and manipulative tactics.

PROS:

• phone support

CONS:

• makes mistakes parsing past returns
• makes mistakes losing NOL carryforwards
• bad GUI on the app and near unusable on the web app
• deceitful. For example there are unnecessary animations to create the illusion of intense processing when parsing takes 1s at the most, checking against IRS rules no more than 10ms

CONCLUSION: I am surprised Intuit didn't land itself a class action lawsuit for making mistakes in tax filing. Their lobbying efforts sure pay off.

iFlight XL8 and DJI FPV

PROS:

• Very strong
• X configuration
• Can fit the DJI FPV air unit when mounted above the Matek F405-CTR
• Perfect size for long range (8" props are expensive, I use 7" props instead)

CONCLUSION: A great frame for HD long range, smooth flight when combined with the iFlight ION 2506-1250

Linksys WRT1200ac - Zero Problem

PROS:

• works flawlessly!
• file sharing from USB drive works (Uninstall>Turn Windows feature on or off>SMB 1.0)
• 4 gigabit links

CONS:

• SMBv1 for file sharing
• slow for 2019, still pushes 60 MB/s in file transfer over the air

Conclusion: If you don't need 200 MB/s over the air, buy this because, unlike newer models, it works without a glitch.

TP-LINK ARCHER AX6000 - Fast But Faulty And Unhealthy

PROS:

• blazing fast
• good tech support

CONS:

• 5GHz AC drops frequently and doesn't reconnect until reboot
• head buzzing when wifi is on (we keep it off at night because of that)

CONCLUSION: don't buy

K210 Maix Bit - neural network in the palm of your hand

What's that?
The K210 was released last year by crypto-mining chip maker Canaan and sipeed build devboards and a python layer that work very well. The dev boards are cheap and well made, including screen and cheap ov2640 camera, it's plug and play, almost.

PROS:

1. small
2. power efficient
3. crazy good value for the price
4. fast enough to do mobilenet v1 at 28 fps
5. very decent documentation and API especially for a 6 month old hardware
6. very responsive dev team that'll help you
7. NN in keras means easy to design your neural net and train it
8. two builds of the python firmware include openMV! 
9. include a neural net accelerator, hardware FFT and can handle a 7 microphone array for sound location!

CONS:

1. linux heavy so you'll have to setup a lot of things right, the easy way:  https://github.com/laurentopia/Learning-AI
2. toolchain somewhat convoluted, requires a lot of setup also but once it's working it's a few clicks to convert from .h5 to k210 native format
3. toolchain a bit green so you may run into problems but there are people to help on the telegram channel

If you've never done anything neural net related, get it, it's really good.
If you're seasoned, get it, it's fun and fast.

Early Detection : Is your EV200D a lemon?

The Eachine EV200D have excellent picture and reception... when they work.
There have been reports of quality problems and since Banggood provide zero customer support or repair, it is best to know if you have a lemon before the 30 return window expires.
This guide is meant to help you gauge how lucky you got at this QC roulette.

1. shake the goggles - some units have lose elements in them
2. power a vtx with camera with enough juice for a few hours, set it at at pit W or 25mW
3. connect a 2A 5V usb power to your goggle, aftere 3 beeps and a few seconds you'll get image
4. select or scan to find your vtx - if lock doesn't work on the first time verify that you are feeding these 5V 2A. If you still have no final lock, power all off and reverse the power on sequence.
5. check that the image is good on both goggle panels - There has been report of dust in the optics and also bluriness
6. insert a microSD, turn on DVR and record
7. let it sit for a couple hours, recording
8. during this time you can 
1. move the vtx+camera+power around to check commutation between the 4 receivers and how DVR handles snow, power off then on the VTX, go out of range etc...
2. put the goggles on your head to check for heat, noise and vibrations - The Raeon display hardware get so hot that Eachine added a cooling blower that runs constantly. This tiny blower runs at high RPM so any defect magnifies vibration.
9. after the test period, look through the optic to verify that the image is still good (some units lose a color component in certain conditions) and verify that your DVR recorded the amount of time that it was on.

If you pass this test, you are a lucky one and should play the lottery more often - seriously, enjoy flying with these amazing 720p goggles.

If some parts of the test fail and that bothers you, you can ask for a refund for up to 30 days, past that , it was reported that BG is unwilling to do anything but you can try, Paypal is your nuclear option so it is highly recommended to use it to pay for these goggles.
Since BG cannot fix these goggles, what they do instead is send you a portion of your money back (60 to 90%) or sends you a new unit for $30 and you keep the other. Which is awesome if you're into modding.

If you want to mod them, for example to quiet down the buzzer or the CPU fan, you can ask on the telegram group.

EV200d - Amazing Image, Faulty Reception, Zero Support

PROS:

• stunning image
• great reception
• cheap
• Banggood will refund a portion in case of problems

CONS:

• reception loss in mid-air
• very power hungry
• lose lock or reboots in midflight
• some units have bad contact so you may lose one color component on one display
• some units have faulty cooling fan that vibrate the unit
• very slow scan
• gets very warm
• some optics have specs of dust in them
• hard to open without breaking, no support or parts available

FIX:

• Fan/heat: https://t.me/EV200D
• loss of lock: plug a 10A power pack to the USB of the battery
• no first lock: do a full scan

CONCLUSION: Buy it at your own risk, some batches are flawless. If yours have problems, contact BG and escalate until you get a 90% refund, you get to keep the goggles, then you can tinker with it to fix most issues. Then buy a HD system.

Using openCV to study a resilient rat

One rat still remains in our house, we see its little droppings in the living room and the stench from under the sink. The pest control are having trouble capturing it so I setup a cheap wide angle camera and observe.
Sifting through 8 hours of footage ain't fun so I asked the help of OpenCV based DVR-scan as well as ffmpeg.

Here are the command lines on Windows:
To merge bits of videos:
(for %i in (*.mp4) do @echo file '%i') > mylist.txt
ffmpeg -f concat -safe 0 -i mylist.txt -c copy ../../output-2019-04-26-08.mp4
To extract footage motion from hours of video:
for %i in (output*.mp4) do dvr-scan -i %i -o scanned%i.mp4

You need is ffmpeg and DVR-scan