My Alarm Clock

2016-12-10-13-18-09My alarm clock was a Christmas gift from my older sister in 1984 when my family was living in Papillion Nebraska (just outside Omaha).  I wanted an alarm clock so I was pleased to receive it, but I do recall mild disappointment because it wasn’t a fancy clock radio combination.  The alarm clock has been used regularly for 32 years and I hope it keeps working.  Devices have supposedly gotten a lot smarter over the past three decades, but I really like my dumb device.

I didn’t get a clock radio, but that’s fine since I don’t listen to the radio much.  When I did listen to the radio a lot, I had my boom box for my room, a Walkman for riding the bus, and when I was older, a stereo in the car.  Instead, my alarm clock just displays the time.  The bright red display can be read in the dark.   The numbers are large enough that the time can be read from across the room and glasses are not required when peering from bed to check the time.

I hate the sound of the alarm–this is a good thing.  I can sleep through a lot, but my alarm is relentless.  Some alarm clocks stop beeping after a minute, but mine will keep producing its throbbing tones for as long as it takes for me to smack the snooze button or switch off the alarm.  The alarm does a good job in waking me.

Apart from setting the time (and alarm time), there is very little maintenance required.  Since it receives power from an outlet, there are no springs to be wound.  There is a backup battery that allows the clock to function if the power goes out, but that only needs to be changed every few years.  There is no need to configure a wifi connection or do any Bluetooth pairing.  There are no online accounts to be created to use it and the clock can be used by anyone in the family without difficulty.

Compared to the alarm clocks available today, mine is a dumb device and I like it that way.  My alarm clock tells the time and wakes me in the morning.  It is reliable and requires minimal effort to use.  I can see the appeal of the fancy, but I plan to stick with my alarm clock from 1984.


I love it when a plan comes together

After spending a lot of effort and encountering difficulties in creating pieces, I am often pleasantly surprised when the pieces come together quickly and easily.  This was the case for my latest home improvement tech project.  In my home, it seems like some areas are warmer than others–I realized that some variance will exist, but I wanted to reduce the overall difference between upstairs and downstairs.

The first step was to be able to measure the temperature or each area.  Thanks to my ESP8266 development boards, I am able to publish the upstairs temperature and publish it to a database and Bakboard.  With the new Nest thermostat and a little playing with the REST API, I was able to do something similar and publish the downstairs temperature to the BakBoard.  There are now four temperatures published on the Bakboard.


I then wrote a simple Java program with that basically does the following:

  1. Get the temperature of the [Downstairs] thermostat
  2. Get the temperature of the [Upstairs] temperature sensor
  3. If the difference between the two temperatures is greater than 2 degrees, turn on the furnace fan

I had a little trouble figuring out how to turn on the fan, but this is the way I implemented it in Java:

public void runFan(String thermostatId, String authToken) throws Exception {
    final String rootUrl = "";
    HttpPut httpPut = new HttpPut(String.format("%s/devices/thermostats/%s/fan_timer_active", rootUrl, thermostatId));

    StringEntity putEntity = new StringEntity("true");
    httpPut.addHeader("Content-Type", "application/json");
    httpPut.addHeader("Authorization", "Bearer " + authToken);
    CloseableHttpClient httpclient = HttpClients.createDefault();
    try {
        CloseableHttpResponse response = httpclient.execute(httpPut);
        // We need to handle redirect
        if (response.getStatusLine().getStatusCode() == 307) {
            String newUrl = response.getHeaders("Location")[0].getValue();
            httpPut.setURI(new URI(newUrl));
            response = httpclient.execute(httpPut);
        try {
            HttpEntity entity = response.getEntity();
        } finally {
    } finally {

Of course I want my code to run at regular intervals, but fortunately I had already figured out how to go about running a Java program every 15 minutes.  It was easy to toss everything into a Docker container and let it do its thing.

Here are a few notes/design decisions that I made when putting things together:

  • There are no changes to the basic functionality of the Nest thermostat.  It is not aware of the external temperature sensor and heats/cools as normal.  This means, even if something goes wrong in my code (or network connection or custom hardware or somewhere else), things can’t go too crazy.
  • My code does not control the length the fan runs–it starts the fan and lets the Nest take care of turning it off.  There is a default run time that can be set on the thermostat–in my case I set it to 15 minutes to match the run duration of my new program.
  • I have a two stage furnace and when just the fan is run it goes at half speed.  Even at full speed the furnace fan is pretty quiet, and at half speed we don’t even notice.
  • The thermostat only gives me the temperature in degree increments (if I were using Celsius it would be in half degree increments).  My homemade temperature sensor goes to greater precision, but it’s hard to say whether that greater precision provides better accuracy.  I went with a 2 degree variance threshold for enabling the fan to allow for rounding differences as well as accuracy differences between upstairs and downstairs temperatures.

As far as I can tell, everything came together smoothly and “just works” and has been for the past few weeks.  Occasionally I check the log to make sure it’s still running.  Once in awhile when I walk past the Nest I notice the fan icon indicating that the fan is running (and I can verify that by putting my hand near a vent).  The weather is still mild, so it will be interesting to see what happens when it gets colder (especially when I rev up the wood stove), but so far there seems less variance in temperature throughout the house.  I love it when a plan comes together . . .

Playing with the Nest Rest API

I bought the Nest thermostat for fun. I purchased it couple months ago to go with the new furnace and air conditioner. I could have gone with a thermostat provided by the contractor, or any number of cheaper options, but I wanted something with which to play. Even though I don’t consider myself a “gadget person”, I wanted this gadget.  I wanted to play with it’s API and see what I could make it do.

With summer ending and school starting, there was a lot going on in the household.  Also, we went for about a month when neither air conditioning nor heating were required, so internal climate control was not often on my mind.  Now the heat is coming on for a few minutes in the morning and I’ve started playing with the Nest Rest API.

The Nest developer website has documentation that helped get me up and running.  As usual, the trickiest part in getting started is figuring out how to authenticate, but that actually went smoothly (I’m not sure whether I’m getting better at doing that sort of thing, or if the Nest process and/or instructions are better).  I was then able to read information about my Nest thermostat.  It was when I tried to write data that I ran into problems.

I had many failures in trying to perform a write.  At first I tried various incarnations of Java code to perform a REST PUT, but I had a variety of problems and errors.  I simplified things.  I tried a simpler use case.  I removed Java from the picture and just used curl.  Eventually I resorted to the instructions I found to change the target temperature on a thermostat:

-H "Content-Type: application/json"
-H "Authorization: Bearer c.lPg4Z..."
-d "{"target_temperature_f": 72}"

I plugged in my own authorization token and device ID, but still it wouldn’t work.  After a lot of kicking and swearing and reading various websites and forums, I came up with:

-H "Content-Type: application/json"
-H "Authorization: Bearer c.lPg4Z..." 
-d '72'

The key differences are:  1) The “-L” flag tells curl to follow the 307 redirect that is returned, 2) Passing just the desired value instead of a JSON snippet, and 3) Specifying the variable name as part of the URL.

When I plugged in my authorization token and device id, things worked–by the time I had taken the seven steps from my disheveled desk to the thermostat, the new value had taken affect and the Nest was turning on the heat.

Although there was some frustration along the way, I had fun playing with the Nest Rest API and am glad I was able to get some basic use cases to work.  Now that I know how to read and write data, I can make make something interesting.

Running a Java program every 15 minutes

I wrote a simple Java program that I wanted to run every 15 minutes.  I decided to wrap everything into a Docker image so that I would get the logging, restart capability, and portability goodness that one gets for free when running a Docker container.  It’s not a difficult thing to do, but it took me longer than it should since I made some incorrect assumptions.

Since I wanted the image to be small, I went with an “Alpine” version of the openjdk image.  My first incorrect assumption was that I could use cron and crontab like I do on Ubuntu or Red Hat systems–but Alpine doesn’t come with cron.  However, it’s actually easier than messing with crontab–I just had to put my script into the /etc/periodic/15min directory.

Once I had the script in place, I tried to run the container, but eventually discovered the the small Alpine image does not have the daemon enabled when the container starts up.  This was solved by running crond in the foreground.  Here’s a Dockerfile showing the important bits:

ROM openjdk:alpine
MAINTAINER Nathan Bak <>

# Create directory to store jars and copy jars there
RUN mkdir /jars
COPY jars/*.jar /jars/

# Copy bin directory of project to root directory
COPY bin/ /

# Copy runJavaApp script into correct location and modify permissions
COPY runJavaApp /etc/periodic/15min/
RUN chmod 755 /etc/periodic/15min/runJavaApp

# When the container starts, run crond in foreground and direct the output to stderr
CMD ["crond", "-f", "-d", "8"]

Here is the runJavaApp script:

java -cp /:/jars/commons-codec-1.9.jar:/jars/commons-logging-1.2.jar:/jars/fluent-hc-4.5.2.jar:/jars/httpclient-4.5.2.jar:/jars/httpclient-cache-4.5.2.jar:/jars/httpclient-win-4.5.2.jar:/jars/httpcore-4.4.4.jar:/jars/httpmime-4.5.2.jar:/jars/jna-4.1.0.jar:/jars/jna-platform-4.1.0.jar com.yellowslicker.sample.Client

The “gotchas” I ran into with the script include:

  1. The script must begin with #!/bin/sh (out of habit I tried #!/bin/bash, but Alpine doesn’t come with bash)
  2. Each jar must be listed explicitly (I tried using /:/jars/*.jar for my path, but it didn’t work)

There are a lot of ways to schedule things, but this method was simple (once I figured it out) and I think it is robust.  In my case, it also fits well into the Docker microservice environment I’m running.

Sherlock Holmes: Predictable and Original


Several years ago, my wife and I purchased a collection of Sherlock Holmes stories as a Christmas present for our niece and I mentioned that I had never read any Sherlock Holmes save an abbreviated version of Hound of the Baskervilles I encountered in fifth grade.  I believe my wife was appalled at this dearth in literary knowledge and as a remedy I soon received a nice version of the Sherlockian canon.  I like to consume literature in bulk–there was no intimidation at 2000-3000 pages, but rather a comfort of knowing there were many hours of reading material immediately available to me.  And so I began.

I really enjoy reading about the various adventures of Sherlock Holmes, but initially I was surprised at how well I could predict the outcome.  Not only did I out pace Watson, but sometimes even the great sleuth himself.  Initially I assumed I was just incredibly clever, but soon reality set in there was the realization that, though the details were different, the “twist” was something previously encountered.  I had read various mysteries including a binge with Agatha Christie while in college.  Before that I had ready Hardy Boys novels (also in mass quantities) and watched episodes of Scooby-Doo.  Sherlock Holmes was quite original when it was written, but it has since become the foundation upon which most modern Western mystery is built.

I think I enjoy the short stories more than the novels; that’s odd considering my general preference towards quantity.  The short stories come across as more tightly written and more focused on the mystery rather than a lot of back story.  Also, since I usually had a good idea where the story was headed, I think I missed out on a certain measure of suspense.

Even though most modern readers won’t be thoroughly astounded by the genius of Sherlock Holmes because of the predictability, it’s not due to lack of originally for it is the original.  Reading the text is a fun journey to the early days of the mystery genre.  If you haven’t yet experienced the world of Holmes and Watson, enjoy the originality and don’t fret the predictability.

The Parable of the Soccer Coach

A coach went to coach a soccer game and place his players on the field.

And as he coached, some players fell into pleasant conversation and failed to notice the game going on around.

And some players went running all over the field after the ball at a full sprint regardless of where the ball went.

And as the minutes passed they quickly tired and, because they had no stamina, whined for a sub.

And some failed to spread out and instead ended up in a clump of players resembling a rugby scrum; and the flailing feet and elbows caused bruised shins and sore ribs.

But others played their assigned positions applying practiced skills to the best of their individual abilities and together they had great plays: some scoring goals, some making assists, some playing a solid defense.


Running a Docker container when the machine starts

Normally when I have a Docker container that I want to automatically come up whenever the machine restarts, I simply use –restart=always when running the container (or “restart: always” in a Docker Compose YAML file).  Recently encountered a situation where that didn’t meet my needs.  I thought it would be quick and easy to start the container from a service (a la systemd).  It ended up being easy, but it wasn’t as quick as I thought because I made some incorrect assumptions and sloppy mistakes along the way–so in case I need to do this again I am documenting what I did here . . .

I was using an Ubuntu 16.04 machine and for my example I’m using my Beaverton School District Calendar image.  To create the actual service, I created the file /etc/systemd/system/schoolCal.service with the contents:

Description=School Calendar Service



There’s nothing special about the service definition, it basically runs the script.  The problem I encountered when creating the service file was I forgot to add the dependency on the docker.service (I’m not sure if both “Requires” and “After” need to be set, but at least one of them does).  To enable the service I ran:

sudo systemctl enable schoolCal

Here are the contents of the script:

docker pull bakchoy/beavertonschoolcalendar
docker run -i --net host -p 9999:9999 bakchoy/beavertonschoolcalendar

The script is very simple, but it took several tries for me to get it right.  Here are some details I encountered/considered:

  • It’s necessary to make the script executable
  • The explicit pull means that the latest image will always be used when starting up a new container.
  • Since I want the container log to be available via journalctl, the container has to be run in interactive mode “-i” instead of in detached mode.
  • Normally when I run stuff in interactive mode, I use “-i -t”.  When I had that, the script worked fine when I ran it manually, but when invoked by the service it would fail with “the input device is not a TTY”.  It took me awhile to figure out the fix was simply to remove the “-t”.
  • In this case, I wanted the container ip/hostname to be the same as the host, so I set “–net host”.  In most situations that probably isn’t necessary.
  • Space isn’t an issue here and I have a different mechanism for cleaning old containers.  Otherwise I might have added a “-rm” (but I’m not certain it would work as expected).

I found which also has an example invoking a Docker container via systemd (and upstart), but it seems closer to using a Docker restart policy than what I’m doing.  Although in general I think using the built-in Docker restart policies is a better approach, here are some aspects that differentiate my approach:

  • No specific container tied to the service–a container doesn’t need to exist for things to work when the service is started
  • I pull request can be included to basically provide automatic updates
  • Logging can be directed to the standard service logging mechanism (such as journalctl)
  • The service can be monitored with the same tools for monitoring other services rather than Docker way

My New Toy (Part 4)

I finally got to the point where my new toy is able to publish temperature information to a database, so next is to make that information available on BakBoard.  With the main pieces already deployed, the only thing necessary is to add the necessary connections.

First I wrote a some JavaScript to poll the Webdis/Redis server for the temperature.  For extra credit I also have it contacting the FAA Services REST API to get information about weather at the Portland airport.  Below is “temperature.js”.

function temperature() {
    window.setInterval(function(){ updateTemperature(); }, 100000);

function setupTemperature() {
    $('.temperature').html("<div class='pdx'/><div class='upstairs'/>");

function updateTemperature() {
    var myJson;
    var url = "";
    myJson = $.getJSON(url, function(obj) {
        var f = parseFloat(obj.GET);
        var c = (f - 32) * 5 / 9;
        $('.upstairs').html("Upstairs: " + f.toFixed(1) + "F (" + c.toFixed(1) + " C)");
    url = "";
    myJson = $.getJSON(url, function(obj) {
        $('.pdx').html("Airport: " +;

And here’s a very simple HTML file that uses the script above to display the airport and upstairs (where I put my new toy) temperatures:

        <!-- I downloaded jQuery from>
        <script src="jquery-2.2.0.min.js"></script>
        <script src="temperature.js"></script>
        <div class="temperature"></div> 

Viewing that script in a browser showed:

Airport: 73.0 F (22.8 C)
Upstairs: 71.1F (21.7 C)

I basically added the bold HTML parts to the BakBoard .html file along with some css goodness and the temperature information is now displaying on BakBoard.


I had fun playing with my new toy and learned a lot.  The ESP8266 seems to have a lot of potential and I want to try more things.  Of course now that I have my only module in use, I may have to get another one for play . . .

My New Toy (Part 3)

In my previous “New Toy” post I managed to wirelessly publish a count, so I determined the next step to be to publish some “real” information: the temperature.

I’m not the first to use an ESP8266 module to publish temperature information and I found an excellent tutorial on Adafruit.  However, it was written for another (now discontinued) ESP8266 module with significant differences from my Electrow.  Also, the sample code provide has the module host a web server and allow clients to connect to it whereas I wanted my module to push the information to a database.  This meant I could use the tutorial as a guide, but there were still various things to figure out.

First I had to do the wiring to connect the DHT22 temperature and humidity sensor I purchased like the one used in the tutorial.  I ended up spending a lot of time and muttering various working words trying to get it to work right.  My module has onboard USB and a voltage regulator, so the wiring is much simpler, but I couldn’t get any readings.  I tried resistor changes, testing connections, and verifying voltages among other things.  Finally I discovered that when I specify pin 2 it means D04 (the fifth digital pin) on my board.  So here’s what I ended up with:

2016-08-02 15.35.48

  • The ground pin connects to the fourth pin of the DHT22 (black wire)
  • The D04 digital pin connects to the second pin of the DHT22 (white wire)
  • The 3.3v pin provides voltage (via the red wire) to the both the first pin of the DHT22 and it also goes through a 10K resister to the second pin.



The code is basically pasting together the Adafruit sample code with the code I wrote previously.  It looks like this:

#include <ESP8266WiFi.h>
#include <DHT.h>
#define DHTTYPE DHT22
#define DHTPIN  2

const char* ssid = "name of wifi network";
const char* pass = "wifi network password";
const char* ip = "";
const int port = 7379;

// Initialize DHT sensor 
DHT dht(DHTPIN, DHTTYPE, 11); // 11 works fine for ESP8266
void setup(void)
  WiFi.begin(ssid, pass);
  while (WiFi.status() != WL_CONNECTED) {
void loop(void)
    float temp_f = dht.readTemperature(true);

    WiFiClient client;
    client.connect(ip, port);
    String url = String("/SET/temperature/") + temp_f;
    client.print(String("GET ") + url + " HTTP/1.1\r\n" +
           "Host: " + String(ip) + "\r\n" + 
           "Connection: close\r\n" + 
           "Content-Length: 0\r\n" + 

I had already started up a Webdis/Redis server as described before, so I could verify it worked by running curl and confirming that it returned a value (in this case 72.68F).

$ curl

Searching online, I found the ConnectSense CS-TH Wireless Temperature and Humidity Sensor that seems pretty much like what I made, but in a pretty box and costing $150 (granted it does come with some nice software as well).  Now that I have my own budget version, I can look to do something with that temperature data I’m collecting.

My Boots


Last week while backpacking in the Mount Jefferson Wilderness area, I had a sad incident related to my boots.  There was a stream crossing, but the stream wasn’t running too high, so I just walked right across.  Boy#1 and Boy#2 were with me and neither had waterproof footwear so I went back and carried their packs across so that they could lightly hop across on rocks without wetting their feet.  By then some of the other boys in the party had caught up and I ended up carrying over another three or four packs.  I got my pack on again and started hiking again, and then I noticed that my right little toe was damp.  The seal failed and my boots are no longer waterproof.  It is time to buy new boots.

My boots were purchased back in the late 1990’s, so it’s been awhile since I’ve had to select new boots.  I’ve been thinking about some of the attributes I like about my boots.  In no particular order:

  • Vibram soles – The soles are worn such that the writing is no longer legible on the yellow emblem, but there is still tread.  I rarely wore my boots on man made surfaces which I think contributed to their longevity.  I always had the traction I needed.
  • Waterproof – as long as the water didn’t go above the top, my feet were dry.  The leather upper and integrated one piece tongue are joined so that there are no gaps in the outside barrier.  It was nice to be able to tromp right through water without worrying about wet feet.
  • Step-in crampon friendly – I’ve never done enough mountaineering to justify fancy plastic shell boots, but being able to quickly slap on some crampons for an ascent has been nice.
  • Sturdy lacing system – I’ve got skinny feet, so I really need to be able to tighten things down.  One of the original laces broke back in 2000 while hiking in Rocky Mountain National Park, but I found a store in Estes Park that sold shoe laces by the foot; I took off the unbroken lace and bought new laces in classic red.
  • Smooth lining – With my bony heels, I tend to wear through the back of shoes before anything else.  The smooth lining slowed that wear significantly and also helped to avoid blisters.
  • Ankle support – The boot came up high enough that it gave great ankle support.  The smooth padding allowed me to have the ankle be tight but still comfortable.
  • Classic – My boots have the classic, Italian style look of a hiking boot.  They are simple, honest boots.

I’m sad that it’s time to retire my boots–I’ve had many adventures with them on my feet.  I’m also excited to find new boots and have some new adventures.