Even as the US blows past 3,000 COVID-19 deaths today, it is important that people realize: it didnt have to be this way. There are places all over the world where competent leadership and reasonable populations have kept COVID-19 at bay and are living otherwise normal lives. As an added benefit, their economies are also relatively normal and people aren’t getting sick and dying.
The Point of No Return
I have the mower drivetrain (sorta) working. The chain slips off occasionally but if I am gentle with the throttle it seems ok. Because I had originally planned to go with a direct drive, the chain gears it down yet another notch. So max speed might end up 2 – 3 MPH. Probably ok for mowing.
Up until now I could easily re-assemble the pieces and go back to a traditional gas engine power. There comes a point when you have to make a more serious commitment to a project like this and going back is not an option. I think I am at that point. I pulled the blades and pulleys and disconnected most of the wiring. Next is draining and removing the gas tank and lastly, getting the engine out.
Then I’ll mount the electronics and start thinking about a for a test drive and details for the mower blades. Right now I’m planning on multiple (4 or 5) small motors driving small circular metal bladed made for string trimmers.
A Damn Stupid Thing To Do
I know mostly the Bell Labs side of this story, and did not know any of the UK part of the history of the C programming language. I still have a hardbound copy of the “K&R” C book on my bookshelf. From Ars Technica.
“A damn stupid thing to do”—the origins of C
Mower Drivetrain Working
Again, I’m not really a mechanical guy (my specialty is electronics) but so far so good. Made an appropriately sized chain and bolted everything down. I ordered a chain tensioner (whatever that is) on line. Hopefully it will all fit together. Resisting the urge to bolt the seat on and go for a ride. Oh, need another battery. Running this 24V motor at 12V right now.
Mower Drivetrain
Started getting serious with the mower. I had the new motor on the bench working and now all that is left to do is install it. This is all experimental for me, so I’m hoping to be able to put it all back together an carry on with the the old gasoline engine if things don’t go well. To get more room to work I took off the seat and fenders and disconnected some wires. I feel like I’ve crossed a line here.
While I would have preferred direct drive, for very practical reasons I have decided to go with chain drive. The electric motor is made for a standard 8mm T8F chain common in modern electric scooters and such. I decided to stick with this since modifying it looks difficult. On the other end I have a large pulley made for a drive belt. It is attached to the transmission which has a spline shaft connection (I’m learning lots of new terminology here). I couldn’t find an 8mm sprocket that would hook to the transmission shaft so I figured the path of least resistance is to get a sprocket and drill and bolt it to the existing pulley. So far not hard. I also drilled and mounted the motor and things seem to fit well. Could probably even upgrade to a more powerful motor without much work if needed.
Now that I have this 8mm sprocket the smaller sprocket on the motor means a lower gearing. I was expecting a 1:1with the direct drive. Right now it is something much smaller. I found a bigger sprocket I can easily swap for the one that came with the motor, but it still is geared down a bit. We will see how that all works out. Have a chain and some bolts on order and probably need a tensioner. Figured I would deal with that once I have all the other pieces more or less put together. Then it could be getting close to a test drive.
COVID-19 and the Economy
There seems to be a belief (not mine) that there is a trade off between managing COVID-19 and damaging the economy of a country. Certainly harsh shutdowns will stop the spread of COVID-19, but this also should allow things to re-open more quickly. Some actions may also make more sense than others. Some good data from Our World In Data.
From this chart, up is more deaths and to the left is more economic damage. You want your country to be in the lower right. You don’t want your country to be in the upper left. Peru seems to be a sad outlier, but I don’t know much about what they have done in Peru. The US, Italy and UK have had lots of deaths but relatively moderate economic damage, at least when this graph was compiled. The winners (so far) Taiwan, South Korean and Lithuania. Indonesia and Japan are not far behind and are large countries. I’ll note the good outcomes of island nations in Asia. Even the Philippines isn’t doing so badly. Asian countries appear to be better prepared because of previous experience with other similar virus outbreaks like SARS. Being an island seems to help with controlling the spread from other countries.
Which countries have protected both health and the economy in the pandemic?
Peak Oil
From Blomberg. I think this could happen even more quickly than this article indicates, especially as solar and batteries keep on their current curves.
Peak Oil is Suddenly Upon Us
Hot Raspberry Pi
My downstairs TV Raspberry Pi 4 started showing a little thermometer icon in the upper right corner while I was streaming some hi-def video. Turns out it was overheating, or close to it. I didn’t put the fan in since I put heatsinks on the processor and two other chips and didn’t think it was necessary. But I suppose under heavy use, especially streaming video, heat gets to be a problem. I snapped the fan in, plugged it in to the 5V on the header and the temperature quickly dropped 40F. Now I wonder if my WiFi problems on my desktop were heat related. Both my Raspberry Pi 4s are now on ethernet, so I’ve stopped fighting the wifi battle.
Raspberry Pi 4 Video
I decided to put a Raspberry Pi 4 on the downstairs TV, with the vague idea of watching streaming media. We already have an Apple TV and a Chromecast, but their mirroring is always more complicated and lower quality than advertised.
Getting set up was easy. Bought an 8GB CanaKit on Amazon and it arrived in one day. I used the default install of 32-bit Raspberian OS as a test, then installed 64-bit Ubuntu. The only hiccup was using 20.04 LTS, which didn’t come with an included user interface. No problem, I can install Gnome. Except modern Ubuntu servers seem to secretly do a security update in the background by default, which blocks any other updates or installs. Once I figured this out it was off to the races.
I went to YouTube for a video test and the results were disappointing. Slow, pixelated and choppy. I know the processor in the Raspberry Pi 4 has a pretty decent Graphics Processor (GPU) so performance should be better. A bit more Googling showed it needed to be enabled at the kernel level.
Some earlier postings showed how to rebuild libraries and the kernel, but that seemed like too much work. It did look like later postings using more recent kernels could enable the GPU with a single line in a configuration file and a reboot. I gave it a try, adding the lines below to the /boot/firmware/usercfg.txt file.
disable_overscan=1
dtoverlay=vc4-fkms-v3d
The first line just fixes the annoying black borders around the display and allows the full screen to be used at full resolution. I’m not sure why this isn’t the default. The second line enables the GPU. After a reboot you can tell if it works by looking at the Graphics field in the About page in Settings as below. The default (slow) software graphics interface is called llvmpipe. It should now say V3D, the 3D “Vulcan” graphics driver.
After this change video was smooth and fast, even in a browser. I was impressed. It also seems to help with regular desktop rendering. You may also need to do special enabling in applications such as Chrome and VLC.
Steven A. Guccione 