Posts

streaks vs statistical streaks

Sep 26, 2016

Hacker News et al are obsessed with streaks, but I think they have some problems:

  1. A single regression resets to zero.

  2. There's not an easy way to gradually ramp up your streak-commitment over time.

I prefer a different approach: statistical streaks.

Suppose I made a commitment to do something differently on 2016-08-26, and did it for the next 5 days; then my 30-day statistical streak avg = 0.166, but my 5-day statistical streak avg = 1.0.

If I then have one off-day (5 consecutive days then one failure day) the 30-day statistical streak avg is still 0.166, but the 5-day statistical streak avg drops to 0.80.

If I pick it back up the next day, it goes to 0.2 and 0.80 for the 30- and 5-day statistical streak averages (respectively), while if I fail again, it drops to 0.1667 and 0.6 for the 30- and 5- variants, respectively.

Here's a tiny bit of python to demonstrate these scenarios:

    assumed_history = 0
    explicit_recent_history = [1,1,1,1,1,0,0]

    for window_days in [30, 5]:
        # lazy...
        history = [assumed_history]*(window_days)+explicit_recent_history   
        recent_history = history[-window_days:]
        success_days = sum(recent_history)

        print window_days, float(success_days) / window_days , recent_history

i fucking love mangoes

Apr 24, 2016

Specifically, the Philippine Brand Dried Mangoes. They are amazingly good.

But there is a slight problem. Costco sells them in 30 oz bulk packs, which is 20 servings at 160 calories/serving or 3200 calories total. Left to my own devices and lack of self discipline, I could probably eat (and subsequently regret eating) the entire bag of mangoes.

I need a self-check to disgust myself and impose a bit more of a speedbump than an already-opened bag provides. So I fired up the FoodSaver and made individual serving sized-bags:

individual_mango

Each was individually weighed to be one serving:

individual_mango_weighed

I ended up making 20:

individual_mangoes

switching over to https

Apr 15, 2016

One of the things I've been meaning to do forever is switch things over to https. By "things", I mean the set of websites I run for some family and friends. I tried it out with my personal website first, then flipped over the rest.

implementation notes

  1. I used the letsencrypt start guide to generate the certificates.
  2. Modified the nginx config to: a. serve ssl/https traffic on port 443 for the given domain with the proper https certificates/etc. b. forward non-ssl/http traffic on port 80 to port 443 for the given domain

verification

It turns out that the nginx configuration files are a little bit error prone. This probably means that I am doing something wrong, like not using some configuration management tool like puppet or ansible or whatever. But for something as small scale as my site, it doesn't really meet the cost-benefit threshold for learning a new tool/language. I also even considered spinning up a simple one-off configuration generator that I'd need to figure out how to override and extend as needed.

My first step was to write a simple requests call that can get the response given a scheme and hostname:

def check_scheme_host(scheme, hostname):
    url = "{scheme}://{hostname}/".format(
        hostname=hostname,
        scheme=scheme,
    )
    try:
        resp = requests.get(url, allow_redirects=False)
    except Exception:
        return None
    return resp

Note that our check disallows redirects, because otherwise requests would just helpfully follow the 301s. Since the 301s are part of what we're trying to verify, we don't want to follow them.

Given that that function, we can define our expectations for a given check. In particular, we can define a function that expects a certain response code for a given hostname and scheme:

def expect_check(expected_response, hostname, scheme):
    actual_response = check_scheme_host(scheme, hostname)
    if actual_response != None and actual_response.status_code == expected_response:
        return hostname + " passed " + scheme + " check!"
    else:
        return hostname + " failed " + scheme + " check!"

Finally, we can check a given hostname:

def check_host(hostname):
    print expect_check(301, hostname, "http")
    print expect_check(200, hostname, "https")

This would let us make calls like

check_host("traviscj.com")

which would print out something like

traviscj.com passed http check!
traviscj.com passed https check!

With that in place, we need some definition of which hosts we want to check. Obviously, we could just define it in the python source, but it'd be nice to make it a bit more reusable. So let's define a simple JSON file that includes the hostnames that I want to ensure work correctly. Here's a sample of a few of them:

[
    {
        "host": "bovineherdhealth.com"
    },
    {
        "host": "priceofth.at"
    },
    {
        "host": "traviscj.com"
    }
]

and a tiny bit of file loading logic:

def from_file(hosting_check_filename):
    with open(hosting_check_filename) as hosting_check_file:
        hosting_check = json.load(hosting_check_file)
        for entry in hosting_check:
            check_host(entry['host'])

and finally, a tiny final bit wiring:

def main():
    from_file('/Users/traviscj/hosting-check/hosting_check.json')

if __name__ == "__main__":
    main()

And now we have a way to test all the host forwarders.

inspired by magicmirror

Jan 2, 2016

I've been really inspired by the MagicMirror project. The basic idea is getting a piece of mirror glass and putting a monitor and computer behind it, then having a status page show some pertinent information about the day (like weather, calendar, news, etc). So it looks like a regular mirror, but when you look closely, it shows the extra information.

I'd like to put one in the bedroom to replace our tall mirror. That'll be pretty cool, but it requires a bit of extra thought because our magicmirror setup would replace a tall and skinny mirror, so we'll probably just want a monitor behind the top part of the mirror. That will require some extra bracing to hold the monitor up in the frame. I'll need to think about that a while.

To hold me over in the mean time, and get a platform to play with the software, I ordered a Raspberry Pi 2 and small screen. With that, I'll be able to play with it on a small scale first. I was thinking about mounting it inbetween two cabinets in the bathroom, but just realized that might not work well with the steam from showers and soforth.

One thing I'd really like to see out of it would be bank & card balances. I guess I'm a little obsessive about that stuff, but it really would be nice to have it. This desire sent me down a big rabbit hole of trying to get OFX transactions downloaded. Of course, it seems nearly impossible. I was about to give up, but then stumbled across the fantastic mintapi python package.

individual sealed ibuprofen & zyrtec

Dec 30, 2015

Today I made some individually sealed ibuprofen (Advil) and cetirizine (Zyrtec) packets:

ibuprofen

I did it by cutting about a two inch strip of vacuum sealing bag, then doing several perpendicular seals far enough apart that I could pop a couple of pills in it.

ibuprofen strip

Why bother? Mostly, I want to keep a few doses in my backpack / car, but don't want them turning into dust. (The softer coat on Kirkland seems especially problematic.) The next best idea is of course just buying the commercial version, but I don't really need 50 packets at a time. I'd prefer to keep more stock in the "more liquid" bottle form. Finally, waterproof can't hurt!

I meant to do double seals, so it'd be easy to separate the cells. I remembered on the first seal, but then I forgot to do this on all the others. So I had to very carefully slice down the middle of the seal. This probably wouldn't be sufficient for food storage, but it seems like it'll be fine for storing dry pills.

I cut small notches on each packet so I might have a chance at tearing them open without tools. I cut the bag almost exactly the same width, but the Ibuprofen bags wouldn't really vacuum because I put two Ibuprofen pills per slot. I had to settle for just sealing them.

It took about 10-12 minutes to do a row of 10 pills the second time I did it. I could probably get faster if I did it a bit more often. Cost calculations clearly reflect consumables only, and in particular don't reflect the cost of the vacuum sealer and other tools.

first canning adventure: brandied pears

Dec 29, 2015

I've been wanting to get into canning for a while. It was finally time to take the plunge. I made brandied pears. One of the really striking things is how simple the ingredients list is:

  • pears
  • lemon juice
  • sugar
  • water
  • brandy

Here's the setup just before I started:

canning prep

Allison got me a pressure canner/cooker for Christmas:

pressure canner

It's huge! After I cooked the pears I packed them

packed pears

and mixed the brandy into the syrup

brandy for pears

and eventually got them into the cans, sealed and processed:

brandied pears

They are delicious! I think I'm going to try something next that requires the pressure canner's features, so I've got a few things on my list:

pragmatic edc

Dec 27, 2015

Lots of folks wax poetic about their every day carry kit, and then include things like fishing hooks. That might make a "pragmatic hiking edc" kit, but I'm interested in some of the more realistic things that might happen:

  1. Phone is dead and need to call someone (wife, parent, car insurance company, whatever) but don't have the relevant phone number / insurance number / etc.
  2. Minor illness like headache, indigestion, things like that.
  3. Forgot my wallet at home and need lunch or cab fare. 4.

purell sanitizing hand wipes pac-kit hydrocortisone pac-kit medication triage pack

recent projects - sous vide, hydroponic pump, and another table

Nov 17, 2015

I've been working on a few fun projects recently.

First: I built a temperature controller out of a crock pot and a cheap import temperature controller. It looks like this:

temperature controller top

temperature controller bottom

I've used it to cook eggs and steak. Both turned out great! Here's the only shots I got of the steak:

steak vacuum sealed steak cooking

Next, I've put together another refinement of the hydroponic tomato setup we have in our living room. Also, just realized I haven't added the backposts about it yet. Allison and I started three tomato plants back in May:

Start

They've grown into this:

Grown

That is a thirsty plant, so I rigged up a small electric pump to refill the bucket from a larger water container below:

hydroponic pump

Finally, I've been wanting some more desk space at home, but haven't wanted to get a full size desk replacement. I wanted to make something with the same construction as the coffee table project, but was wary of starting another hand-sawing project. So I got one of the Makita circular saws! It is impossible to overstate how much easier it made the project. The original coffee table took several days of work and hand sawing, while this time I had done most of the cutting in about a half hour! under desk table parts

Then I assembled the sides:

under desk table sides

and put the top on, then put it in place:

under desk table unstained

I haven't stained it yet, but wanted to get a feel for fit and usefulness before that. One of the first things I realized was that it was really dark on the shelf. A long while back, Mom had given me some snazzy LED strip lights, so I gave them a try:

under desk table lit

build_json.sh

Aug 19, 2015

This might seem silly, but I've beeing playing with some json.sh scripts that build legitimate json bodies and are easily filled into a shell script variable as needed.

The basic driving idea was that there are lots of slick ways to pull data out of JSON(either by programming something with python's json or running a command line tool like jq or whatever), but not as many friendly ways to build some JSON out of a given token or whatever. Often, you have a list of identifiers and you need to build a bunch of JSON blobs from that list.

For example, say we have a file called things that contains

thing1
thing2
thing3
thing4

and we need to generate

{"value":"$THINGTOKEN"}

for each token in things. Then we can simply run a tiny shell command like

Traviss-MacBook-Pro% while read token; do
> echo $(newBuilder | set value $(quoted $token) | build)
> done < things
{"value":"thing1"}
{"value":"thing2"}
{"value":"thing3"}
{"value":"thing4"}

Easy as that! There's no waiting for heavy VMs to start up or anything like that, just run it.

carputer brainstorming ideas

Jun 7, 2015

As much as I enjoy driving, radio almost always annoys me. There's a couple of particularly terrible stations and commercials around, but even the least objectionable of the pack really bother me. The focus did come with an auxiliary stereo input plug, which we have used extensively, but even that seems to have some shortcomings. In particular, one of the things I really miss about the radio approach is just that I don't really need to think that much about it -- it is just there while I'm driving around. Starting up spotify after I've started off isn't safe or prudent.

I started thinking about ways to improve this, and I think I finally came up with a workable idea.

The plan is to use a raspberry pi wired to the electrical system and stereo auxiliary input. I think the Pi should start up fast enough to start playing music shortly after starting the car, and with an SD card loaded with music should have plenty to not get bored with. I also realized that if I used some program like MPD to handle the music playing, I could probably remote control it from the iphone. That might require another hack or two (like a Linux-compatible USB/WiFi or bluetooth network adapter), but it would be pretty awesome to have phones in the car able to select the music. The Pi is cheap enough that I could probably just hide it under the front seat in the car and not be very worried about it getting too hot/etc, and I could power it out of the 12V phone charger that I already plug in to charge my phone.

The other cool part about this is that if I ever manage to get my radio installed in the car, I can potentiaally use the Pi (or some other computing unit) to send APRS packets or whatever.

Anyway, the actual setup:

  1. Install Debian on the Pi, along with apt-get install mpd.
  2. Copy a bunch of music onto the Pi SD card, either directly or by scp-ing files over.
  3. Hook up the Pi to some speakers and troubleshoot the mpd installation.
  4. Move the Pi to the car.
  5. Ensure the wifi still works.

Next step will be running some machine learning analysis on the MPD play logs to see if I can build some really awesome playlists.

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