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Car ball and nut steering

April 30, 2019 — BarryK

A different blog post from usual!

Modern cars have "rack & pinion" steering, which gives tight (minimal sloppiness or deadzone).

Many years ago, cars had "ball & nut", or "recirculating ball", steering. The main problem with this is a deadzone, or sloppiness, which got worse as the linkakes/bushes wore.

I was reminded of this recently, when read about the new 2019 Suzuki Jimny, and posted to this blog:

http://bkhome.org/news/201903/new-suzuki-2019-jimny-4x4.html

I was surprised that this Jimny still has ball & nut steering.

Back in the 70's I owned an early Suzuki 4wd, one of the "LJ" series, with a 2-stroke engine. I recall, it was dangerous on wet roads. Especially a wet road with tight bends -- I found that the steering would get out of my control, and I had to slow right down.

In the mid to late 80's, I owned an old Holden, an "EH" model I think, a 3-speed automatic. I was cash-strapped at the time, and bought this secondhand. Don't recall what price I paid, but do remember selling it for AU$300.

It had various problems, such as tending to overheat -- but they made engines out of iron in those days, it could survive repeated overheating.

It had the old recirculating ball steering, don't recall if it was power steering. It was worn, with considerable slack. Near where I lived, there was a dirt road, that turned to mud when it rained. I discovered that when driving home on that road, and the car lurched to the right, the steering wheel snatched violently out of my hands. I pulled the wheel left, and it got snatched out of my hands again as the car lurched to the left.

Thus I zigzagged across the road, until I had reduced speed to a crawl.

The problem was the tyres sinking slightly into the mud. If the front tyres turn very slightly from true forward direction, a small wall of mud then forces them to turn more. Which can happen due to the slackness in the steering linkages. When the wheels have been twisted more than a few degrees, the wheels get violently pushed to the side, and the steering wheel spins out of my control.

So, pretty awful type of steering, hey! However, I am over-dramatizing the risk. My Holden was old and the steering linkages very worn. If I had got it fixed, replaced some bushes, the steering slack would have tightened up considerably, and I would probably have been able to race straight through that muddy road.

Apart from the Jimny, apparently some trucks still have this, I don't know about other 4wd vehicles.

With the Suzuki 4wd cars, a popular after-market addon was a "steering damper", a hydraulic mechanism that will minimise the kind of scenario that I have described above.

It seems that Suzuki added it to the Jimny 4wd series, and it is in the 2019 model. Thank goodness. There is also power steering, so it would seem that the two mechanisms would be fighting each other -- well, apparently, it does cause the steering to have a "dead" feel, with no feedback from the wheels.

Why hasn't Suzuki gone over to rack & pinion steering for the Jimny? I don't know, there must be reasons. I don't know enough about the topic to guess why. More info here:

https://en.wikipedia.org/wiki/Steering

Quoting:

The recirculating ball mechanism has the advantage of a much greater mechanical advantage, so that it was found on larger, heavier vehicles while the rack and pinion was originally limited to smaller and lighter ones; due to the almost universal adoption of power steering, however, this is no longer an important advantage, leading to the increasing use of rack and pinion on newer cars.

The steering damper does make driving safer, however there is another concern. The deadzone means that the front wheels are not necessarily going in the direction in which you are pointing the steering wheel. This has been observed by testers of the 2019 Jimny on highway driving, where the car tends to wander to left or right, and has to be continually corrected.
This means that the driver has to be always alert, and it does make the driving experience more tedious -- though, the continual correction does become habitual. I also briefly owned a Suzuki 1.3 litre Sierra, the model after the LJ series and before the Jimny series, and I recall this wandering problem, but I adapted to it and found highway driving to be OK, if a bit odd.

Thought that I would post these interesting observations! 

Tags: tech

New Suzuki 2019 Jimny 4x4

March 05, 2019 — BarryK

The little Suzuki 4-wheel-drive car has a long history. I owned an original model in the 70s, an LJ50 2-stroke. It was awful driving on the road, fantastic off. In the mid-80s I briefly owned a Sierra, with 1.3 litre 4-stroke engine, and as I recall, if was OK driving on the road, and took it for country trips -- it was even OK on the highway -- but then, my standard was probably quite low, as I had always owned very small cars.

Both of those were purchased second-hand. Now it is 2019 and Suzuki are advertising a brand new Jimny. The Jimny models superseded the Sierra models. The advertised price here in Australia (by Suzuki Australia, the importer) is AU$23,990 plus on-road-costs.

I enquired with local Suzuki dealers, and they are asking AU$27,990 drive-away price. That is a big jump from AU$23,990. Am I getting cynical in my old age? A cynical person might think that the price hike is cleverly contrived. And then there is an extra AU$500 for any colour other than white.

You see, Suzuki announced that very limited numbers would be imported, which resulted in pre-orders, and a growing backlog -- they are now saying, if you order now you will get it in 2020. Meanwhile, the rave reviews and marketing hype continue to build up the expectation.

There is no discount, you buy at the price they ask, and go into the waiting list. I am drooling over it, very fond of that little car, but probably won't buy one. Suzuki, if you put it on sale later this year, you will tempt me...

EDIT:
It seems that my cynicism was misplaced. Suzuki was genuinely surprised by the sales of the new model. They have one factory in Japan running 23 hours per day, and are planning to utilize another plant.

img1

Australian Suzuki distributor:

https://www.suzuki.com.au/vehicles/suv/jimny

Review:

https://www.carsguide.com.au/car-reviews/suzuki-jimny-72749

There are plenty of YouTube videos, here is one with some on-road testing:

https://www.youtube.com/watch?v=oGnrZDuCUwQ

An off-road video:

https://www.youtube.com/watch?v=4nIcqx23kl8 

   

Tags: tech

PinePhone development kit

February 02, 2019 — BarryK

Wow, this is interesting! Those who read my blog, will know that I have purchased the Librem 5 phone development kit, as reported here:

http://bkhome.org/news/201812/purism-librem-5-dev-kit-is-shipping.html

Mine arrived a few weeks ago, yet it remains unused. I am waiting until they get the LCD screen to work. Apparently, it is a software driver problem, rather than a hardware fault (thank goodness), but the screen is the most essential component, that must be working.

Another worry is the immaturity of the NXP iMX 8m SoC. Apparently, there is a fault in the chip as supplied with the dev kit, that prevents it from going into a lower-power mode -- the Purism developers reported this to NXP and it is, apparently, scheduled to be fixed.

Even so, it is a concern, as the iMX8 has been "in the pipeline" for a long time -- first announced in 2013.

The Purism developers have been doing incredible work on the software side, and hopefully the hardware issues will be resolved in a reasonable time frame.

In the meantime, another group has produced a "copy". Well, not a copy exactly, but very similar, a phone development kit, named the PinePhone, based on the Allwinner A64 SoC. Photo:

img1

As with the Librem 5, this has a separate modem -- you can see it in the above photo.

The SoC's used in phones all have the modem built into the SoC. Purism are using an SoC without modem, as by keeping it separate they can keep a watch on what traffic goes between SoC and modem, for improved security.

So, the PinePhone is using the same security-minded approach, and targeting the same market, and will be running the same Linux OS's as the Librem 5. They don't mention it, but no doubt it will also run the OS that the Purism guys are developing.

The PinePhone will be on show as FOSDEM 2019, here is a blog post:

https://forum.pine64.org/showthread.php?tid=7093

Pine64 are the same guys who make the Rock64, which I own and have just today released EasyOS for. The above blog also announces an improved Rock64, including RTC.

Anyway, the Allwinner A64 SoC, how does that stack up for use in a phone, and for Linux compatibility?

This is a great page to get a birds eye on Linux compatibility:

http://linux-sunxi.org/Linux_mainlining_effort

Here is a report on upstream Linux support for the VPU:

https://bootlin.com/blog/allwinner-vpu-support-in-mainline-linux-november-status-update/

...how this pans out in practice, remains to be seen. All very interesting! 

Tags: tech

SanDisk Ultra 32GB USB3 Flash drive

January 14, 2019 — BarryK

I posted yesterday about a very cheap Verbatim 16GB STORE-N-GO USB2 drive:

http://bkhome.org/news/201901/bottom-rung-usb-flash-stick.html

...sooo slow, then it failed after a few days.

I have to comment about this failure. Most of the Flash sticks that I purchase, including the very cheap ones, last for a very long time. Well, I have only had a couple of failures in several years. I even have a 128MB drive that is still working.

That Verbatim drive went into the bin, couldn't be bothered with taking it back.

This morning, wen to BigW and bought a SanDisk Ultra 32GB USB3 drive, for AU$14. That's it's regular price, not discounted.

Now we're cookin' with gas! I wrote the Russian build of Easy to it, and got a sustained sequential write speed of 28.7MB/sec.

Compare that with 3.9MB/sec for the Verbatim drive. It is so much worth it, to spend that little bit more! 

Tags: tech

Bottom-rung USB Flash stick

January 12, 2019 — BarryK

Today I purchased a Verbatim STORE N GO 16GB USB2 Flash stick, at AU$4.25, from Officeworks.

I just wanted something cheap. I write different builds of EasyOS onto Flash sticks, each labeled with masking tape, and keep various older ones. Consequently, sometimes run out of a spare one to write to.

Anyway, thought that I would post this as a warning to others: recommend buy a more up-market Flash stick for testing EasyOS!!!!

I used the 'easydd' utility to write the EasyOS 0.9.18 image file to the Flash stick, and it recorded a write speed of 3.9MB/sec.

This is down at the absolute bottom. I did get around that figure with an Emtec stick. My experience is, cheap Verbatim and Emtec Flash sticks from BigW, Officeworks, etc., are not just low-cost, they are also extremely slow.

At the other extreme, is an SSD at about 150MB/sec write speed, see test here:

http://bkhome.org/news/201812/thoughts-on-hdd-and-ssd-speed.html

If you want a fast USB Flash stick, the best that I have purchased is a Sandisk Extreme, giving around 100MB/sec. But you don't have to go that far. Pay a few more dollars than AU$4 and you can easily get around 7 - 20 MB/sec. A cheap USB3 stick will usually give faster performance than a USB2 stick.

Anyway, after writing 0.9.18 to the verbatim STORE N GO, booted it. It was not a pleasant experience. A lot of waiting is required.

The most alarming event was after clicking the "www" icon on the desktop, a "starting for the first time" window popped up, and then disappeared, and then.... nothing. waited and waited. Began to think that I had done something wrong with this build, then suddenly SeaMonkey window appeared.

Using it now. Once underway, it is working OK.

This post is a warning. Do not test running Easy, or any Linux, using the cheapest Flash stick in your collection. Use the best one. 

EDIT 2019-01-14

Oh man, it gets worse. This Flash stick is only a few days old. I installed Easy 0.9.18 on it, have booted a few times. This morning, started to boot it, and got an error:

Copying EasyOS to RAM, then mounting
cp: read error: I/O error

Only 4 bucks, won't take it back, just throw it in the trash bin. 

Tags: tech

Crucial MX500 500GB 2.5inch SATA SSD

January 02, 2019 — BarryK

I wrote recently about the very pleasant experience installing a Kingston 240GB SSD in my Mele mini-PC:

https://easyos.org/install/how-to-install-easyos-on-a-new-ssd.html

The speed improvement is so phenomenal compared with HDDs, and the price has dropped, enticing me to move my main midi-tower PC to using a SSD. So, I have now purchased a Crucial MX500 500GB 2.5inch SATA3 SSD, for AU$109:

https://www.austin.net.au/shop-categories/hard-drives-ssd/crucial-mx500-500gb-sata-25-7mm-ssd.html

img1

What has prompted this purchase, is that I have redesigned the layout of my projects for easier backup. Up until recently, my projects over the years have been "all over the place". Also, "build" folders are inside the projects -- for example, a compile for a particular architecture, say x86_64, in oe-qky-src, is inside the project folder. same thing for woof, building a release of EasyOS happens inside the woof project folder.

This makes the project folders enormous. oe-qky-src for example, a compile may occupy a hundred GB or more.

So, I have redesigned all of my projects into one folder, named bk, with all builds taking place outside of bk. Downloaded source packages, however, are kept within bk, as there is no guarantee they will always be available online.

The size of bk is 408GB. This includes old projects, such as t2, as well as recent woof and oe-qky-src. The size is convenient, it will fit nicely into that Crucial 500GB SSD.

At first, I backed up bk to a 1TB USB3 hard drive ...and it took several hours. Hmmm.

I have decided to backup in a crude way, not incremental. No raid either. Just copy the entire master bk folder, or even the entire partition, or even the entire SSD. If I also have an SSD external drive, the internal SSD could be backed up in less than half an hour.

That "500GB" is of course not really true. fdisk shows that it is actually 465.8GB, or 500107862016 bytes. If they were using a KB as 1000 bytes, not 1024, then 500107862016/1000 is 500107862KB, and 500107862/1000 is 500107.862MB, and 500107.862/100 is 500.1GB ...yeah, correct. 

The manufacturer's site:

https://www.crucial.com/usa/en/storage-ssd-mx500

Has this interesting statement:
Integrated Power Loss Immunity: Avoid unintended data loss when the power unexpectedly goes out. This built-in feature of our new NAND protects your data swiftly and efficiently, so if your system suddenly shuts down, you keep all your saved work.
There is also hardware encryption, but only available with certain software on Windows. Anyway, I read somewhere that it is very easy to break. 

Tags: tech

Purism Librem 5 Dev Kit is shipping

December 24, 2018 — BarryK

I backed this project in June this year:

http://bkhome.org/news/201806/librem-5-an-open-source-linux-phone.html

I did think that their timeline was incredibly optimistic, which it has turned out to be, too optimistic, that is.

I have received an email, my Dev Kit is on its way. Here is their blog post announcing the shipping:

https://puri.sm/posts/2018-devkits-are-shipping/

image1

There is a worry here, they are still on a tight timeline, and have shipped the Dev Kits despite not having confirmed that all of its components actually work -- or so I gather, from reading status information that they have emailed to me.

If the issues turn out to be software related, and not hardware faults, then OK. A lot of very bright people will be getting these kits, so we can hope that the issues will get resolved.

One thing, the touch screen is not yet working. Of course, it is essential for that to be functional, and it is a bit of a concern that they have shipped the kit before getting that working.

After the Sentio Superbook debacle, I am wary. But, will stay in a positive frame of mind, as there will be a few hundred very knowledgeable guys playing with this kit.

I haven't ordered the phone yet. Actually, my main interest is in the Dev Kit itself, as it has all the components of a smartphone, with development software, so is a great way to become familiar with programming these interfaces.

Tags: tech