EEVblog Electronics Community Forum

EEVblog => EEVblog Specific => Topic started by: EEVblog on November 20, 2019, 02:19:35 am

Title: EEVblog #1263 - Mailbag
Post by: EEVblog on November 20, 2019, 02:19:35 am
Mailbag time!



https://www.youtube.com/watch?v=pt2CgSphN58 (https://www.youtube.com/watch?v=pt2CgSphN58)

SPOILERS:
Automated Factory robot laser scanner teardown
Siemens & Schneider Electric safety timer switch teardowns.

18:54 HTC Vive VR Base Station Teardown

37:35 40W 180V Nixie tube driver: https://www.tindie.com/products/nexus/40-watt-high-voltage-nixie-power-supply/ (https://www.tindie.com/products/nexus/40-watt-high-voltage-nixie-power-supply/)
https://neonkev.com/2019/10/15/success-201-boost-at-40-watts-without-a-transformer/ (https://neonkev.com/2019/10/15/success-201-boost-at-40-watts-without-a-transformer/)

45:07 Hadou-CAN USB CAN adapter: https://www.tindie.com/products/suburbanembedded/hadou-can-usb-can-fd-adapter/ (https://www.tindie.com/products/suburbanembedded/hadou-can-usb-can-fd-adapter/)
Title: Re: EEVblog #1263 - Mailbag
Post by: johnlsenchak on November 20, 2019, 04:35:21 am

Great Scott Outback Dave ,  at   18:36 minutes  you incorrectly  called   the IRF840  a  transistor, it's  actually  a  MOSFET  8) 8) 8)

https://components101.com/sites/default/files/component_datasheet/IRF840-Datasheet.pdf
Title: Re: EEVblog #1263 - Mailbag
Post by: maginnovision on November 20, 2019, 05:22:43 am
metal–oxide–semiconductor field-effect transistor
Title: Re: EEVblog #1263 - Mailbag
Post by: johnlsenchak on November 20, 2019, 05:41:00 am
Good  call  it may  say it's a transistor, but it's does  say "field-effect transistor"  and  acts   more like a  vacuum  tube, then a straight   dual P/N   junction  transistor that's either  NPN  or PNP    I'm  just defining  the difference  between  the two even though  they both  either switch  or do gain


Sort of  like a  Triode  and a Pentode , both are " Vacuum  tubes" , and they both either   switch  or do  gain for amplification  . But their   functionality on  how they operate   internally  is  different due to how it's manufactured 
Title: Re: EEVblog #1263 - Mailbag
Post by: FrankBuss on November 20, 2019, 08:47:22 am
Found a nice video what the HTC Vive tracker does:

https://www.youtube.com/watch?v=J54dotTt7k0 (https://www.youtube.com/watch?v=J54dotTt7k0)

Here (https://skarredghost.com/2017/06/07/need-know-steamvr-tracking-2-0-will-foundation-vive-2/) is an explanation how it works, includes the video as well. Accuracy is about 1.5 mm, and it even works with just one station (with less accuracy).

I once tried a HTV Vive VR, and it is amazing how good the tracker is. But the headset was not very comfortable, and the field of view and display resolution not that great, and at least when I tried it, the image was only sharp in a small area, e.g. I couldn't read text when it was not in the center. Maybe needed some calibrations or adjustments. I tried a Microsoft Hololens as well, and it was much better, but much more expensive as well.
Title: Re: EEVblog #1263 - Mailbag
Post by: Pack34 on November 20, 2019, 10:38:06 am
@Dave,

The serrations you noted in front of the image sensor on the scanner are called baffling. The purpose is to mitigate stray light issues. The image sensor does a good job absorbing the light, but light coming into the system can be off-axis and bounce off the sides. In general, this would reduce the SNR of your resulting image or create false images and ghosting. Another method to mitigate stray light is the finish and painting of the optical channel. This is one of the practical applications Vantablack. 

Related reading:
https://www.newport.com/t/stray-light-in-monochromators-and-spectrographs (https://www.newport.com/t/stray-light-in-monochromators-and-spectrographs)
Title: Re: EEVblog #1263 - Mailbag
Post by: NivagSwerdna on November 20, 2019, 04:09:05 pm
"Don't eat the desiccant" such wise words...  I wonder if bigclive eats his?

"Desiccants are the most common foreign object ingestion by children under 6 years of age"

Sounds like the choking is the issue, so probably best to eat them in small pieces.
Title: Re: EEVblog #1263 - Mailbag
Post by: thinkfat on November 20, 2019, 07:51:18 pm
I remember a huge thread here on the forum about development of a high voltage power supply for Nixies, was that the same guy? Must have been about half a year ago.
Title: Re: EEVblog #1263 - Mailbag
Post by: jonovid on November 20, 2019, 09:36:01 pm
HTC Vive VR Base Station has what looks like two spinning laser lines
the corrugated or ripple laser lens on the side of rotating drum outputs a sweeping line.
laser beam gos down the middle, axis of the drum. rotating cylinder & mirror.
two spinning laser lines give you X & Y if your motor degrees of rotation is a know value.
by timing your laser lines a 3D space is mapped out.  robot eyes

the tools & Bits  8)
quality hand tools gos next to quality test equipment.
a must have. for my bench.  :-+
Title: Re: EEVblog #1263 - Mailbag
Post by: numloxx on November 21, 2019, 12:20:38 am
Glad you got my postcard. They have so much stuff at the Heinz Nixdorf Museum in Paderborn. I spent the entire day there. Huge calculator collection as well.
https://www.hnf.de/en/home.html (https://www.hnf.de/en/home.html) - Museum
Calculator collection - https://twitter.com/numloxx/status/1171713415745888256 (https://twitter.com/numloxx/status/1171713415745888256)
Enjoy :)
Title: Re: EEVblog #1263 - Mailbag
Post by: station240 on November 21, 2019, 06:32:40 am
Those USB to CAN adapters are handy for debugging, or capturing traffic for reverse engineering.
I should be doing more CAN stuff at the moment, but the last CAN device I bought of ebay isn't turning up |O

Seems there are two versions of the Hadou, bare PCB and cased, so Dave actually has two of these.
Title: Re: EEVblog #1263 - Mailbag
Post by: Fungus on November 21, 2019, 07:53:08 am
Great Scott Outback Dave ,  at   18:36 minutes  you incorrectly  called   the IRF840  a  transistor, it's  actually  a  MOSFET  8) 8) 8)

Do you know what the 'T' stands for in "MOSFET"?

Title: Re: EEVblog #1263 - Mailbag
Post by: ETITsynthesizer on November 21, 2019, 03:21:56 pm
Dave, when you said you didn't have a 40W resistor on hand that was a bit cringey for me. you have $10K in oscilloscopes but you don't have a $3 dummy load? I went on ebay. you can get a 300R and a 500R for $2.20 USD with free shipping. close enough to 810 Ohms to test that nixie driver. please do a part two.

https://www.ebay.com/itm/25-50-100W-0-01-5k-Ohm-Watt-Shell-Power-Aluminum-Housed-Case-Wirewound-Resistor/152815608794 (https://www.ebay.com/itm/25-50-100W-0-01-5k-Ohm-Watt-Shell-Power-Aluminum-Housed-Case-Wirewound-Resistor/152815608794)

at work we have a 600A dummy load built into a (stolen?) shopping cart. we don't have current sense shunts over 150A though. we do all the power supply calibrations at 150A or 140A. then we load test at up to 600A.
Title: Re: EEVblog #1263 - Mailbag
Post by: NivagSwerdna on November 21, 2019, 06:02:06 pm
Dave, when you said you didn't have a 40W resistor on hand that was a bit cringey for me.
I agree. That PSU claims 40W (although I don't know why you need to go that high, I am sure my small tube display draws 5W ish... Maybe big tubes need more). We want to see it cranked up to 11 with smoke coming out and some FLIR action.
Title: Re: EEVblog #1263 - Mailbag
Post by: FrankBuss on November 21, 2019, 07:05:41 pm
Good idea with a short follow up video for the Nixie power supply. In the mailbag video, I expected that he would at least test the short circuit protection with a screwdriver or something, when he measured the voltage. Sometimes they are a bit optimistic with such claims :) Would be a very useful device for me, someday I plan to finish my Nixie clock (https://www.eevblog.com/forum/projects/pimp-up-grandma_s-clock-with-nixie-tubes/). Price is a bit high, but if it meets the spec, and doesn't cause EMC problems etc., I would pay it.
Title: Re: EEVblog #1263 - Mailbag
Post by: Mr. Scram on November 21, 2019, 07:42:12 pm
"Don't eat the desiccant" such wise words...  I wonder if bigclive eats his?

"Desiccants are the most common foreign object ingestion by children under 6 years of age"

Sounds like the choking is the issue, so probably best to eat them in small pieces.
Apparently eating desiccant isn't an issue at all.

"Silica gel is chemically inert and is considered to be non-toxic.  The concern with this substances it that it can be a choking hazard (this is why these packets often say ‘DO NOT EAT’ on them). If your child is choking on silica gel, call 911 immediately."
Title: Re: EEVblog #1263 - Mailbag
Post by: nexus on November 23, 2019, 09:07:29 pm
Hi all,

This is Kevin A. I'm the guy who made the nixie power supply.

I did drop ship Dave the same resistor I used for load testing from Digikey. Hopefully he does a follow up with some load testing.

I did also take some FLIR images and videos of the supply running at a 200 milliamp load on the high voltage. You can check it out at the bottom of the post I did on this topic at: https://neonkev.com/2019/10/15/success-201-boost-at-40-watts-without-a-transformer/
Title: Re: EEVblog #1263 - Mailbag
Post by: 3roomlab on November 24, 2019, 01:28:46 am
that robot warehouse ...
3months after their robot video
some faulty battery charger starts a fire  :(
>GBP100 million lost
(https://www.thenational.ae/image/policy:1.832629:1551618789/bz04-MAR-ocada-fire-damage.jpg?f=16x9&w=1200&$p$f$w=3465ed7)
Title: Re: EEVblog #1263 - Mailbag
Post by: Andrew McNamara on November 26, 2019, 11:49:54 pm
that robot warehouse ...
3months after their robot video
some faulty battery charger starts a fire  :(
>GBP100 million lost

Some decent coverage here: https://www.bbc.com/news/uk-england-hampshire-49071456 (https://www.bbc.com/news/uk-england-hampshire-49071456)

Some key points from the article:
Title: Re: EEVblog #1263 - Mailbag
Post by: Andrew McNamara on November 27, 2019, 12:02:05 am
that robot warehouse ...

Hampshire Fire and Rescue's "Ocado Fire Contributory Factors" brief: https://www.esfrs.org/_resources/assets/attachment/full/0/28939.pdf (https://www.esfrs.org/_resources/assets/attachment/full/0/28939.pdf)
Title: Re: EEVblog #1263 - Mailbag
Post by: mcovington on December 02, 2019, 05:27:01 am
Why not load the 180V power supply with a 240-volt incandescent light bulb?  Better than not being able to do the test at all.