Archive for the ‘Uncategorized’ Category

A Walk Through Sacramento

14 December 2018

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A month ago I was in Chico, where the fire that burned down the entire town of Paradise filled the Sacramento valley with an acrid haze.

The people who could not get into or did not want to stay in one of the shelters were just beginning to figure out how to cope with their new situation.

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A month later…

I decide to take a late morning walk to get a few needed items and take some pictures.

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I start walking south, down 7th. This alley heads towards the old justice building, is shaded by a WPA-era office building, and exits in the middle of an RT (Sacramento Regional Transit) station.

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At the Capitol Building the holiday tree is up.

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While landlords try to contend with all the fallen leaves.

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It’s boring until I get to R Street. This is the newer end of the “Historic R District” development.

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Some folks meet outside the local organic foods market.

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This establishment is named “Fox and Goose.”

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And here, the stores in front of Warehouse Artist Lofts, the original apartment building I was hoping to move into.

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One of RT’s main offices is near their 13th Street station, and sports one of our beautiful murals. Across the street there is another one…

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That’s a Nelson Mandela quote, in case you can’t make that out.

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The older part of the R Street development starts with this posh interior design shop…

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…continues with a chic gathering place serving coffee, tea and pastries…

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…and is framed by the now-old corporate look of a Panda, Safeway, and Peet’s Coffee.

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Included is one of Sacramento’s iconic silver horses.

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Walking up 19th (after shopping at Safeway) I run across this mural.

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The sign on this lot reads “Let Us Grow.”

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Then I hit the beginnings of gentrified downtown, the Golden Road Pub, fabricated from steel shipping containers.

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Ace Hardware is my next stop, and a very important source of supplies in the downtown area. On their roof is mounted a solar panel array, still a rarity in this area.

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This cute little eatery is called “The Porch.”

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And here at 15th, another cafè catering to young professionals. This eatery faces The Kay, the central tourist area of downtown Sacramento and my current neighborhood.

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At this end of The Kay is the Convention Center, some hotels, and some higher-end shops and restaurants. The IMAX theater is here. The children waiting outside the IMAX are actually headed for the outside ice rink near where I live.

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In my mind, a street roofed by a natural arch of mature trees is a street to be proud of. This street, however, has seen better days. Its renovation is far from complete, and with the continuing dominance of the suburbs in modern urban life, it may never be as busy as it was before the widespread use of automobiles.

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Through Bishop Gallegos Square I catch another glimpse of the Capitol Building.

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The children walk through my neighborhood, destined for the DOCO (Downtown Commons). They seemed a bit uncomfortable downtown, but excited.

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They must pass by this RT station on K Street, where a technician is trying to fix some malfunctioning piece of electronic equipment, while holding his flashlight in his mouth.

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Yay! They have made it to the ice rink! But how are that many kids going to fit into one little rink? I will leave them to solve that problem themselves.

The extensive bird droppings are worth noting. These would probably not exist at this level if these trees were not part of a daily stopping place for the local crows. They tend to gather in the evening, hundreds of them. They make an awful racket, and rain down their poop. Then they fly away.

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The police are useless in deterring these errant crows, but I’m sure they serve other useful purposes. DOCO has their holiday tree up, too. One of several, actually. And I have returned home.

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July 4th

4 July 2018

Sheep in the park!

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There is a theory in permaculture that intensive (but not prolonged) grazing can improve open land much better than simply leaving it fallow. It appears this theory is being put to the test at the American River Parkway (area across from Cal Expo). This is one of two sheep pens very recently put up in the park, and there are a LOT of sheep here! They are still getting used to the bike riders.

After visiting these pens for several weekends in a row, I can add that many of the grazing animals being used in the park are actually goats. On my first visit, I found two different pens (also called paddocks) but since that time have only noticed one (they are being rotated through the area) on the river side of the bike trail which is full of goats.

Community Fair at Howe Park

I went up to Howe Park to volunteer at the Way To Happiness table. There was a little parade down through the neighborhood, and it ended up here. The setup was simple but attractive, and there was quite a crowd.

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The booths only stayed until noon. I think the organizers were expecting another HOT day, but the weather today was milder than usual.

The parade was modest – no marching bands – but included some nice old cars (popular in Pullman, too) such as the one shown below.

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Bike path fruits and nuts

As I returned on the bike path through the Parkway, I stopped to check the fig trees. They are dropping a lot of unripe fruit. The problem seems to be that fig trees really need water, and we’ve had no rain for at least a month. The fruit turn soft and pulpy, and tend to fall off, though they are still green and inedible.

The blackberries were doing better. The first fruit are beginning to ripen now, and it looks life a full crop.

The almonds at the city end of the path (near the Diamond facility) are also ripening and are now edible, though not fully ripe.

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Happy Fourth!

Motors Demo

25 October 2017

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I don’t use motors much in my projects, but they are everywhere now on our very mechanical world. So I am always running into them, and had a bunch set aside mostly from tearing down old printers. I have been particularly interested in stepper motors, as I had read about them a long time ago, and they are used a lot in industry.

Stepper Motors

This isn’t going to be a huge technical article, but: Stepper motors are used for positioning in all sorts of equipment, computer printers just being one example. They are designed to be moved an exact rotational amount (by counting the step signals sent to the motor) and to hold that position while energized.

The ordinary stepper motor is driven by two overlapping signals, as mentioned in my recent post about SerDes design. Finding new data about how these motors are driven inspired me to take another shot at creating a working driver. My previous attempt, based on sine waves amplified by audio amps, had not been successful.

Design by Numbers

Here is a rear view of my project, with numbers added to match the discussion below:

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  1. AC terminals and connectors. I like to run my projects off AC-powered supplies. I get them cheap from thrift stores. Usually they are “wall warts” or otherwise portable / external power supplies, and I remove the plastic cover and use the board inside. Sometimes I keep half the cover if it helps for mounting purposes.The funny thing about all modern power supplies is that the first thing they do is convert your AC power to DC. Then they step down the DC (about 120V in the US, about twice that in many other places) to the power supply voltage. Most of these modules provide good regulation, because that’s built into the controller electronics, and it helps protect people and equipment.
  2. I stacked the two power supplies I used. The top one runs my control electronics. Most of it is 5V, but I also have some 12V relays.
  3. I used a 9 volt 3-1/2 amp module to run the motors. These are a little hard to find, so when I run across one I grab it for later use. 5V supplies are ubiquitous, as they are used now for phone chargers (phones generally have 4V batteries). But other voltages and power levels can be more scarce.
  4. Next in line is a board that monitors the motor supply for voltage and current output. You can buy panel meters with these features built in, but I built my own, as it’s not too hard. It then feeds generic panel meters. The hardest part to get right on this board was the current shunt. I used a bunch of SMT (surface mount) resistors in parallel.
  5. The motor driver module was purchased online from China. This particular one had some problems, and I basically had to repair it before I could use it. That sometimes happens with cheap stuff from China. They had installed the wrong part to function as a 5V auxiliary supply. It was supposed to be a fixed-voltage part and an adjustable-voltage part was installed. So I had to lift the adjustment pin off the board and add some components to get my 5V output.One of the drivers was also poorly soldered, so I went over the solder joints and added more solder as needed.

    The board uses a part that has been around for a long time (LM298). It is designed to drive stepper motors. It has four logic-level inputs (plus enable) and four power outputs. It can work up to 48V. I had planned to add a second higher-voltage motor driver supply to the project, but all the motors worked fine with 9V, so I left it out.

    You have to feed the driver the correct signals, and I made two more boards to do that. One board provides the four steps needed to generate the “quadrature” drive pattern and a pulse-width-modulated (PWM) signal to vary the amount of drive. The other board converts these signals to those needed to feed to the driver board.

  6. Another board just gets all the connections right.
  7. I used a four-position rotary switch to select between four different motors. Only one is a stepper motor. The ordinary DC motors are very easy to power on; you just apply power. You can modify their speed somewhat by changing the drive voltage or using a PWM signal which essentially does the same thing. I used one driver IC on the driver board to power the DC motors. I paired up the four drivers to make two. I can run the load in forward, reverse or braking mode.
  8. Here are the front panel controls for stepper speed, PWM, and forward – brake – reverse.
  9. Cheap panel meters from China indicate the drive voltage and total current being used. They have a nice auto-ranging feature which makes them usable up to about 50 volts input. Their electronics run on 5 volts. These digital meters only have three decimal places, but that was enough for this application.

Closing Comments

The biggest problem with motors is having them stall out due to mechanical overload, which can ruin both the motor and the drive electronics. As these motors are running no-load, that’s not a problem. You can grab the motor shaft with your fingers if you want to, and see what mechanical loading does to the current draw. But for real use, the electronics should include overcurrent protection to turn the power off if the motor stalls. Many industrial motor drivers also monitor motor temperature, which is another way to tell that something is going wrong with your motor.

I am very happy that I was finally able to get my stepper motor to run (both forwards and reverse!) and at a variety of different speeds. It turns out steppers are a bit sensitive to what speed you drive them at. Try to go too fast and they just won’t run. Go too slow and they use too much power (though there are ways around this). Most steppers have an optimum speed, and in most applications, you will see them operated at a constant speed, or maybe two, high and low (like in a scanner).

The driver module was designed for robotics hobbyists. It’s a neat design, but not well-documented. I had to look up the datasheets for the various parts used to get details. This is par for the course in hobby electronics.

Power Down in Pullman

6 December 2013

At about 9AM this morning (a Friday) power went out on the factory floor at SEL in Pullman. I thought some might be interested in a few of the technical implications of such an event.

Part of the plant contains equipment that is very problematic if it loses power unexpectedly. That part is protected by a local generator run by a diesel motor, and power to it was restored immediately.

However, that left a large part of the building without electricity.

Cold weather!

The weather here for the last few days has been very cold, never getting above freezing. The low this morning was about 1° F (-17 C) with an expected high of 18. This weekend it will get even colder before a “warm” front moves in next week and causes more rain or snow.

Air temperature and water vapor holding capacity

Very cold air can hold practically no water vapor, whereas hot air can hold a lot. This means that “humid” cold air is actually very dry. If freezing air with a relative humidity of near 100% were heated 40° F it would become very dry air, with a relative humidity of perhaps 25%. Our frigid air currently has a relative humidity of around 70%, which translates to less than 10% at a comfortable room temperature.

Making an ESD safe factory

Electrostatic buildup is a much bigger problem in dry air than in humid air. In a modern electronics factory, maintaining a humidity level of about 40% is an important part of minimizing damage to parts as they are assembled onto boards and the boards get assembled into equipment and tested.

Special equipment is installed to (usually) add water vapor to the factory air to keep it ESD (electrostatic discharge) safe. When our part of the factory lost power, the humidifiers went off, and the air started drying out. By lunch time the humidity had dropped to about 10%. We had lost our ESD-safe work environment. The factory was halted and workers sent home, as it will take about 2 hours after power is restored (which happened around 1PM) for the humidity to be brought back up to a safe level.

“Safe grid” no buzzword

That’s what you call a “negative economic impact” from a power outage.

About 4 hours of production time wasted, even though the power was restored in the middle of the day.

If the outage had lasted longer or been more extensive, it could have knocked out building heating and caused a real human problem, as has been caused by winter storms in the U.S. and elsewhere.

Most infrastructure on this planet has not been built with the idea that weather or other environmental hazards would ever be a major problem. Though this seems a bit fanciful at this point, it is where things stand. If things get real bad on the planetary surface, much of our infrastructure could be destroyed, even if our bodies survive. Evidently, something other than sustainability was on the minds of those who designed and built most parts of our current environment, including the power grid and the generating stations and substations that go with it.

The more sustainable portions of our infrastructure are usually kept secret, as you can imagine them being overrun if some sort of panic ever happened on the surface, if everyone knew where they were. This gives those who do know a short-term advantage. But it’s only short-term.

This planet, as a human society, will eventually pay for the shortsightedness of ourselves and our leaders in creating an environment where instant gratification is much more important than long-term survival. It would be one thing if we took this risk with full cognizance of what we were getting ourselves into. But it didn’t go down that way.

Many of the survivors of the last great cataclysm on earth carried forward lifestyles of (by our standards) severe poverty in order to preserve some semblance of a balance between short-term and long-term survival.

Certain groups took another approach, thinking that material technologies could protect them from any important threat. Though these groups effectively “conquered” the “primitive” groups, our sense of balance was also lost.

We now possess knowledge that could change the future outlook considerably.
We know:
1) We are actually eternal spiritual beings playing the “meat body” game as a sort of pastime.
2) We are not alone in this universe. Many other societies exist out there that are struggling with the same problems we are struggling with.
3) Physical technologies exist or could be developed that would far surpass what we now have and could, for all intents and purposes, solve the survivability problems of meat bodies if we wanted to. Contacts with those other (“ET”) societies have made us aware of this.
4) For the first time, spiritual technologies are also available to us that could enable us to gain full control over our own criminal tendencies and so solve our greatest survival problem, which was: Destruction from within.

Thus a “New Era” is possible on earth and many other locations, if we decide to embrace these various technologies and use them together to improve conditions and move the whole game up to a higher level. If we grab for the material technologies and neglect the spiritual ones, our game could dive to new lows. It’s really all up to us whether “power down” becomes a permanent condition or a thing of the past.

News of the Future – Drone Car

13 October 2012

I have added a new page to my other blog called “News of the Future.”

I invite you to check out my first article here.