Tuesday, January 19, 2016

SNNR web stack: SQLite, NGINX, Node.js, Raspberry pi

I'm writing to introduce SNNR, a "new" web stack: SQLite, NGINX, Node.js running on a Raspberry Pi.  I intend to use this stack for home heat monitoring and controlling.  I had previously built some electric imp based devices to monitor the temperature, and then built some to act as thermostats, and initially I will use this stack to provide a very simple API for the electric imps to store data.  Later it will  provide a web app for users to display temperature data and control the thermostats.  The stack runs on a Raspberry Pi 2 model B running Raspbian, uses NGINX (v1.2.1), Node.js (v4.2.4) and SQLite3.
All code available at this repository on github:  https://github.com/dllahr/home_control/releases/tag/v0.1

Thursday, December 31, 2015

Brewing a Carob Kitchen Sink Stacktrace Porter or A Comedy of My Many Errors

I decided to brew a batch of beer and I wanted to use up any random brewing ingredients I had, so I decided to make "Carob Kitchen Sink Stacktrace Porter".  I had made a carob porter before based on a recipe in The New Complete Joy of Home Brewing "Goat Scrotum Ale" p. 199, so I started from there again, with a few modifications based on my current inventory.  I added "Stacktrace" to the name because a stacktrace is the list of everything that happened during execution of program - generally looked at when something went wrong - and things going wrong is a key component of this brew.

Wednesday, December 30, 2015

Brewing a Second Batch of Mead

We brewed our first batch of mead back around Fall 2009, we were motivated to give it as a wedding present to my sister-in-law who we knew was getting married in 2010 - that gave us a year to let it age.  It turned out pretty well, but it was much sweeter than we would have liked it.  Over the next few years, we noticed as time went on the sweetness diminished and the mead got better and better.  We're down to our last bottle, which is living in my mother-in-law's fridge, so I decided to brew another batch and try to make it less sweet at the outset.

Tuesday, December 29, 2015

Mini-Foundry to Melt Aluminum, Construction and First Attempted Use

My friend Phil pointed me towards this YouTube video in which Grant Thompson (GT) demonstrates how to build a mini-foundry that you can use to melt Aluminum at home and out of common materials, so I decided to try it for myself.  This post will describe how I built it, largely following what GT did in his video demonstration, and a first attempt at using it to melt aluminum.

Wednesday, December 23, 2015

Welding a bottom bracket to my bike

The bottom bracket on a bike is essentially what connects the pedals to the frame and allows them to rotate.  I had replaced the bottom bracket on my bike awhile back, and then a few months ago it came loose.  I initially tried just tightening it down, then tried locktite (red); neither worked to hold it in place.  I took it to a bike shop and asked them about cleaning up the threads, they looked at it and said, "What threads?  There's nothing left."  At that point I decided to try to weld it (TIG welding), but it was ultimately not successful - the welds were very messy, the arc was behaving erratically, and although initially I was able to ride the bike, after~ 4 rides to and from work the welds broke and I was back to where I started.  This post describes my second attempt at welding, which I think will ultimately be more successful.

Edit:  I forgot to mention - I did this work at Artisan's Asylum in Somerville.  They are fantastic!

Saturday, December 19, 2015

Attempted repair of a FitBit Flex

I had an old Fitbit Flex that had stopped working so I decided to try to fix it. (Important note:  Fitbit had given me a free replacement - that's pretty great of them.  I tried this fix after losing the replacement).

The problem I had with this Flex was that the battery got low and then it would not recharge.  My idea was to charge it "manually" by somehow creating a better connection to the Flex from my DC power supply.  Using my multimeter I wasn't able to measure any voltage across any combination of the 3 pins, so my next step was to try to determine which pins should have power or be used to try to charge the Flex.

Saturday, October 31, 2015

Electric Imp Thermostat

I decided to build a thermostat out of an electric imp, which will then be easily controlled remotely and with arbitrary complex programming based on any conceivable input / data.
Starting components, from upper left: electric imp, TMP36 temperature sensor, solid state relay, electric imp breakout board, perf board.  Not pictured:  op-amp