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Quorten Blog 1

First blog for all Quorten's blog-like writings

Looking for laser rangefinder modules, getting more specific

quorten

2018-11-06

Categories: raspberry-pi  
Tags: raspberry-pi  

Okay, let’s keep searching for laser rangefinder modules, this time being more specific.

20181105/DuckDuckGo digikey laser phase shift rangefinder

This is an interesting paper describing a high-speed phase shift laser rangefinder design. It states that previously, laser rangefinder designs that were accurate had to compromise on speed. So, yeah, that’s something to look for. What are the features and capabilities of your laser rangefinder module?

20181105/www.ismtii2011.org/article/xml/sub/file_download.kin?main_no=92&mode=pdf

This is another interesting research article about different laser measurement techniques. From the year 2001!

20181105/https://utdallas.edu/~aiken/LASERCLASS/laserprinlipels.pdf

If you’re in the mood for do-it-yourself on the rangefinder module, there is a PDF on Digikey with a HOWTO for buying parts from them to do just that.

20181105/https://media.digikey.com/pdf/Data%20Sheets/Osram%20PDFs/SPL%20PL90_3_RangeFinder.pdf

And, just when I was about to give up and start a new search query! Bingo, I found a laser module for purchase!

20181105/https://www.acuitylaser.com/products/item/ar1000-laser-distance-sensor

Read on →

Caveats with URL access under Python

quorten

2018-11-03

Categories: python  
Tags: python  

Suppose you have a huge file that you only wnat to download a few parts of it in Python, parse it around like a tar file, and then process the rest as you please, seeking as needs be the case. Unfortunately, I recon that there are no libraries to do this in Python. Well, at least I could find any. If you want to do this processing in Python, your only choice is to download the file whole, process it, and continue. This is especially annoying if your sole destination is to just upload it to another server Failing that, maybe there are some Linux FUSE libraries to make a remote file appear as if it is a local file on the filesystem level, eh? Yeah, that sounds plausible, unfortunately I couldn’t find any sane such libraries for read-only access. Much of the attention given those search terms and concepts seems to be around WebDAV, which we know never became popular enough to be worthy of being considered in practice.

Failed search.

Read on →

More info about IBM acquiring Red Hat?

quorten

2018-11-03

Categories: random-software  
Tags: random-software  

Ah, so I heard that IBM is acquiring Red Hat. Do we have more information about this on the Internet. Well, well, this is what I’ve found. Not much, really. But the point in hand that I’ll emphasize. First of all, IBM has been involved in open-source for quite some time, so in some sense they are prepared to acquire Red Hat and keep it running as it should. Second, IBM is the bigger company of the two, by a lot, so it makes sense that IBM would be the buyer rather than Red Hat, unless Red Hat only bought but a segment of IBM. Finally, we know which of the two companies is the bigger name in today’s world. Interestingly, it’s not a requirement to be the biggest company in order to be the biggest name.

20181102/DuckDuckGo red hat ibm
20181102/https://thenextweb.com/dd/2018/10/28/ibms-acquisition-of-red-hat-is-huge-news-for-the-linux-world/

Weird things with `/dev/null`

quorten

2018-11-02

Categories: random-software  
Tags: random-software  

Weird things that can happen with /dev/null. One thing that apparently happened quite often in the history of Unix is /dev/null getting deleted or replaced with a regular file. So, what are some ways that this could have ended up happening by accident, beyond deleting and messing around with /dev/null directly? Well, here’s one interesting thing that I’ve found out. If you set your Bash history to /dev/null and run as root, and execute more than $HISTFILESIZE commands, then Bash will end up moving /dev/null somewhere else and replacing it with a regular file. Ha, now that is an interesting way that problem can get caused.

20181102/DuckDuckGo /dev/null got replaced by regular file
20181102/https://serverfault.com/questions/551628/dev-null-file-became-regular-file/551644
20181102/https://serverfault.com/questions/551628/dev-null-file-became-regular-file/663642#663642

Quarry?

quorten

2018-11-02

Categories: random  
Tags: random  

Why am I looking up Quarry on Wikipedia? A workgroup decided to use that as their random name.

20181102/https://en.wikipedia.org/wiki/Quarry

Now, this is really interesting, nice, and, well, somewhat funny too. Wheel washing system, so that those dump trucks coming out of a construction site don’t get the roads all dirty with dirt trekked up on their tires. Funny because of what I think about when I saw a big water truck spraying non-potable water down onto the road to wash the road.

20181102/https://en.wikipedia.org/wiki/Wheel_washing_system

What is a Thyristor?

quorten

2018-11-02

Categories: pentax-k-1-camera   raspberry-pi  
Tags: pentax-k-1-camera   raspberry-pi  

So, DSLR camera flashes sometimes tout that they are “Thyristor triggered.” What exactly is a Thyristor? Basically, it is a solid-state circuit that is similar to a transistor, but it only acts as an on-off switch. There is no mode in between where it can act as an amplifier for an analaog signal. Also, they are more rugged for larger voltage swings than transistors and MOSFETs.

20181101/https://en.wikipedia.org/wiki/Thyristor

oVirt blog, checking if there are updates on oVirt

quorten

2018-11-02

Categories: random-software  
Tags: random-software  

So, now I find oVirt to be quite interesting, and I’ve found there’s also an oVirt. So, what is the news on oVirt at this time? Anything interesting recently? Well, I wouldn’t say that there has yet been any interesting release activity. However, I’ve found some interesting technical articles on the oVirt blog detailing some of the lower-level technical details of the system.

20181101/https://www.ovirt.org/blog/
20181101/https://www.ovirt.org/blog/page=2/
20181101/https://www.ovirt.org/blog/page=3/
20181101/https://www.ovirt.org/blog/2017/10/introducing-high-performance-vms/
20181101/https://www.ovirt.org/blog/2017/09/starting-vm/

Xilinx selling FPGAs to Microsoft for AI cloud

quorten

2018-11-01

Categories: random-software  
Tags: random-software  

Random software notes.

Xilinx is in bigger business with Microsoft nowadays now that interest in FPGAs for cloud computer installations is surging, along with higher-level software tools that don’t require as much human engineer involvement in the design process. Intel was previously a big name in this niche use of FPGAs, but now more established names like Xilinx are making inroads too.

20181102/https://www.geekwire.com/2018/report-microsoft-picks-new-chip-maker-ai-co-processors-azure-cutting-intels-business-half/
20181102/https://www.geekwire.com/2018/evolving-cloud-services-need-flexible-chips-portlands-megh-computing-thinks-can-contribute/