Archive for the ‘Random Thoughts’ Category

Over Trained?

24 July 2017

Paid and volunteer civil servants such as firefighters and police deserve respect and praise for their efforts to maintain public safety. Those that have sacrificed to save others should be memorialized to an even greater extent than they are. But here is the difficult question, how many police officers have died from using too little violence? We, sadly, regularly hear of those that have died by police action, with the most notable cases involving unarmed women and children. Maybe those officers were over-trained to pull out and fire their weapon. An action removed from the consequences maybe easier to perform but lacks morality. It is more like the action of a soldier on a battlefield than a police officer in a playground. Maybe police need to train in more non-lethal methods. We live in such a gun crazy country, it would be good to consider how to deescalate potentially deadly situations on both sides of the conflict.

Pantry Cabinet Lights

10 September 2016

I wanted to put lights in a pantry cabinet without spending lots of money and preferably no batteries. The no battery criteria removes many remote switch and motion sensor options, but I had a plan.

As to lights, I liked 2W (~200 lumen or 20W incandescent equivalent) LED disc lamps that could be attached using double sided tape above each shelf. They are powered by an AC to DC converter so no worries about replacing or recharging batteries. Yes, a small wire running from each one, but not too obtrusive. They can be gotten for a couple dollars a disc these days.

I was stuck on a door switch option but I didn’t want the door switch to be operating on AC line voltage. There are some smart house options that you can put together for $150 that will also give you WiFi or Bluetooth control. I really didn’t need that for this and I certainly didn’t want to pay for that.

What I did find was a really cool and inexpensive AC Relay from Digital Loggers (http://www.digital-loggers.com/iot.html). It was designed to allow a Raspberry Pi or the like to control an AC outlet and has several useful features, namely:

One: Compact and easy to use module with power switch, including circuit breaker, and surge suppressor.

Two: Has both normally ON and normally OFF outlets. The usefulness will become more evident later.

Sadly, the control input is not self powered which could lead to a complicated control circuit. I really just wanted to use some magnetic switches like you might find on windows for a security system.

That brings us to #3: the module is easy to modify. Remove 6 screws and it easily opens up. There is no internal 3.3V or 5V DC source in there. Turns out driving the input needs less than 1 mA. There is an isolated (capacitive coupled) bridge rectifier in there but it is very current limited, enough to drive the AC relay but not much more. Temped as you might be to use it, don’t. It can work but I found it unreliable as a source. When the AC relay is activated it pulls down this voltage by 2/3rd.

I suggest adding another rectifier after the power switch. You will loose out on isolation inside the module but that is okay as the magnet switches should still make it an isolated circuit. Add about 10 uF across the input, that would be enough to ride out a half period should you not want to put in a full bridge. 75 kohm is enough for current limiting, use at least 1/2 w (assuming US residential line voltage). One more hint, place all the components top side of the circuit board as it makes it easier to put the board back in the case. Connect the current limiting resistor and rectifier to the + input with neutral as the other. This will give you about 3V across the input, enough to saturate the opto-isolator they use to drive the AC relay. You could just reuse an old 5V phone charger, but they are not as easy to take apart.

Get normally open magnetic switch (they are open when the magnet is away from the sensor). You can get a bunch of them cheap from Amazon (ASIN B0011W4YNK for example) which have nice recessed wire terminals and double sided tape already on the bottom. My pantry had more than one door so I needed more than one switch.

Wire them in series to get any door to turn on the lights. I had a spool of some shielded two conductor wire, the kind used on old (really old) fashioned phone system. Any insulated wire should work. 22 AWG is fine.

Plug the lights into the normally OFF AC outlet. Then they will turn on when the door opens (magnet switch goes to normally open which allows the control input to charge up switching the normally off AC outlet to on).

If you got, for some reason, NC switches then you can still make it work. Wire the switches in parallel and swap the lights to the normally ON AC outlet – why having both types of outlet is useful.

Unconscious Ludicrous Rambling

21 June 2016

Last night my unconscious mind decided to entertain me with what had to be the most ludicrous story. It had a title ‘a stitch in time’ about a bunch of hobgoblins and their leader who can slow time for everyone else while they rob. The protagonist was named Eli who repaired pottery for a living. It all took place in the early 19th century. Eli had invented a steam powered car and used steam power in his shop and somehow could sense the villains presence. He was able to tie the villain so they were stuck in real time at which point they exploded for no apparent reason. But at least it had title.

Then, as an encore, my mind gave me an episode of X-Files about a group of mutated hillbillies who live off sucking electricity and are only caught when the owner of the house they were syphoning from dies unexpectedly which results in the electricity being turned off and their frantic attempts to access new source or hilariously try to make their own.

Searching the Internet about WiFi Speed

2 April 2016

The cable internet service provider, of customer service infamy, offered faster internet at no additional charge. No additional charge seemed like a good enough deal so I signed up. It would be months later, with no noticeable improvement in WiFi speeds in the house, that I did the important test. One we should all do:

Check the speed of the modem wired directly to a computer.

Then I got 90 Mbps. But on WiFi, never better than 20 Mbps and sometimes so bad it seemed that I was back on dialup.

The router said it could do 300 Mbps so it can’t be the problem, right? What does the internet say? Interference, put in a repeater; or bad cable between the modem and router; or peak congestion, retest in the middle of the night; or wrong setting slowing down the router; or, my favorite, encryption is causing the slow down, remove the security and it will be faster.

Of course the best lies have just enough truth to be believed. Any of those could have been true, but nope. 300 Mbps was just the kind of false advertising that confuses and deceives those who don’t dig deep enough into the details. I’m the one who fell for it too. That whole ‘up to’ should have tipped me off. That and also the computer kept telling me it was a 75 Mbps connection to the router.

I just needed a new router. Once I replaced the router the WiFi speed was nearly as fast as being connected directly to the modem.

While normally the internet is really good about answering these kinds of questions, it really didn’t provide the simple answer in this case without a lot of searching. An old N router, even though it says it can do up to 300 Mbps, really won’t get you more than 20 Mbps on WiFi. Now 20 Mbps is more than what you need for almost anything – well one anything, you really don’t have as much as you think once you start splitting that pie up between all the WiFi connected crap we have these days.

So the answer is, if you have fast internet being anything over 20 Mbps, make sure your router is less than two years old first. Likely that is what is slowing down your WiFi.

China, Housing, and Refugees

9 January 2016

I’m told China has a real estate bubble that might collapse and cause a world wide recession, if it hasn’t already. So it got me wondering, just how much over-supply is there? Turns out there is number for that on the internet, and it is that there is currently more than 1 billion square meters of available housing. Yes, billion, with a B. It works out to space for over 25 million average Europeans (or only 14 million average Americans). That would be enough to house every refugee in the world, so one way to end the refugee crisis in Europe. Sadly I somehow doubt China would be so generous with their unused housing.

As it pertains to China, islands, and climate change

19 December 2015

It may be cynical of me, but is it possible one reason China signed on to the latest climate agreement was to protect their investment in island building in the South China Sea? I mean, if any island was to be vulnerable to rising seas it would be man made ones – right?

I wonder how well those islands survive tsunamis. Do they abandon them in bad weather? If so, why doesn’t one of the closer nations go occupy them right after the storm passes? After all, it is just facts on the ground.

10 Years and 100000 Miles

5 December 2014

It was 10 years ago this week that I first drove my 2005 Ford Escape Hybrid. 10 years later, on the road between New York and Illinois this past week, it passed 100000 miles. The original battery still works and it still gets about 27 MPG (4WD). The rust shows that I was not kind to it, no garage for 5 years and not nearly enough car washes. The area above the passenger side rear wheel had to be replaced from the rust. The tone ring keep cracking every couple years, the first time it happened the dealer took a week to figure out what happened. But all in all it has been a good car. It is a good size to carry a family of four on a long road trip without being large and hard to maneuver. It has mostly good site lines from the driver seat. A little underpowered, but expected for a hybrid. Though I often feel bad using hybrid parking spots given the 27 rather than 50 MPG.

The last couple years I think, just one more winter. Well see.

Alright California, here is my crackpot idea to deal with drought

27 February 2014

Remember Star Trek: TNG? Atmospheric condensers!

Well a little more complicated than that. Have floating ocean based platforms that take in humid sea air and cool the air using deep water geothermal cooling which should condense out some reasonable amount of fresh water. Generate electricity for the pumps with tidal power. Hopefully better than desalination.

Best Wishes to All for 2014

31 December 2013

I figure everything in life has a price. For some things the price is insignificant and we gladly pay it. For other things the price is annoying but we grudgingly pay it. Then there are the things whose price is exorbitant and we reluctantly pay it. In this new year I hope you gladly pay for all that you need in life.

LED Light Bulbs and World Population

21 April 2012

There is a relationship between the two, how LED light bulbs could help reduce the stress on world resources, but that really isn’t what I am going to blog about.

I have been trying out LED light bulbs looking for the right combination of brightness and color. The bulb I got from G7 was bright and had a good color but sadly it hummed and not just a few bars. Yes it got quieter after being on for a bit for it was too noisy. My guess, from an engineering background, is that the transformer they used to rectify the voltage was not secured well enough. A manufacturing flaw. Hopefully one they will improve in future designs. I also tried two bulbs from EarthLED. They were bright and quiet but a little too yellow. I guess I needed something ‘cooler’ than their ‘warm’. Who came up with using warm and cool anyway and why can they not try harder to make white rather than blueish white or yellowish white? Well, I plan to keep trying different bulbs till I find a good one.

So the world population is around 7 billion people. From a neighborhood perspective it is really hard to grasp 7 billion. What made me start thinking about population was Hunger Games and the seemingly too small of a population for district 12. Anti-bacterial soap advertises that it kills 99.6% of germs. If something killed 99.6% of humans there would still be a world population of around 28 million. “The Permian-Triassic extinction event, known as the Great Dying, occurred 251.4 million years ago and eradicated 96 percent of all marine species and 70 percent of all terrestrial vertebrates species on earth” and that was the biggest die-off we know of. Yes, sure it is of species rather than populations, but humans don’t really act like one species anymore. Modern medicine and technology have a stronger effect than evolution on the human species right now. So imagine the event it would take to bring the population of district 12 to 3000 from what is currently probably on the order of 20 million, a loss of something like 99.985% of the population. One person in 6000 survives. Well, at least better odds than winning the lotto. It just doesn’t seem possible to have such a large die-off. But people like Elon Musk and Steven Hawking believe that it is a such a real possibility that they support spending large sums of money and effort to have human colonies on other worlds. Who am I to say they are wrong.