Wiring Sparkfun Gas Sensor Breakout

Recently I purchased a few gas sensors from Sparkfun Electronics for use in a couple of projects. Most of the gas sensors have a pin layout which makes them hard-to-impossible to fit into a breadboard. To solve this, Sparkfun sells a Gas Sensor Breakout Board to consolidate the six pins on gas sensors down to four.

I procured a few of those boards with my sensors; after connecting everything together, I was a bit unsure how to wire the sensors to my Arduino. There are technical manuals and a few opinions available on the internet but none of them seemed clear. After some experimentation, I found a wiring scheme which appears to work well and I thought it might be helpful to share it.

Gas Sensor Wiring

Some of the sensors may have slightly different needs but I think this will work for all of the MQ* sensors Sparkfun sells.

As a final note, you should let the sensors “burn in” based on their spec sheets. My CO2 sensor has been on for ~12 hours and has shown a noticeable change in sensitivity for the better.

Creating Neighborhood Networks with Walkscore

I want to find somewhere super livable; aside from “livable” being subjective, it is often hard to find data even if you have specific criteria. The data at Walkscore is really interesting but I see two big problems with it.

  1. The data for an entire city favtors in part of the city I likely do not care about.
  2. The data for one neighborhood is likely too small for the “area” I’d visit most days.

What I really want is a dataset which looks at “networks” of neighborhoods. Specifically, I want the aggregate data for a neighborhood and all other neighborhoods which are within a specific distance. To me, a network is an area which I’d “call home” and like visit frequently. In my case, I consider anything within 3 miles of my neighborhood within my “network” since I can get there on foot, bike, or transit pretty easily.
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Flashing Errors for Android 5.1 on Nexus 6

I recently got a Nexus 6 (yesterday) and Android 5.1 came out today. Being impatient, I decided to flash Android 5.1 myself since it’s been a breeze in the past.

Turns out, I do not think the flash-all.sh script actually works for the Nexus 6. Specifically, I kept getting the following error.
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Raspberry Pi 2.0 Benchmarks

Raspberry Pi 2.0 means it’s time for Raspberry Pi 2.0 benchmarks!

I have run previous benchmarks on various Raspberry Pi units so when I got my Raspberry Pi 2.0, I was immediately curious how its CPU performance compared to my other units. Due to work, my time is limited at the moment but I wanted to get some initial benchmarks out of the door.

So, just how do the 1.0 and 2.0 models compare? Simply, the 2.0 model shows promise.

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Fitbit vs Jawbone – one week of data

Data is awesome and people generate a lot of data. It’s not surprising that a number of companies, such as Fitbit and Jawbone have moved into the space of capturing data from people. it seems that fitness is the first major (adopted) wave of “self quantification” which is being adopted.

Of course, bad data is not entirely useful data. To that end, I’ve wondered about the accuracy of some of these devices. While I cannot address their total accuracy, I have started to poke around whether they compute the same data for the same movements. Specifically, if I wore a Jawbone and Fitbit device for one week, would they have the same data? Fitbit vs Jawbone – one week of data – would I get the same data?

Turns out, no, not really.
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SDR Antenna Comparison

Recently, I have been fascinated with software defined radio (SDR.) There are a number of cheap
USB dongles which fall into the RTLSDR camp. I believe most of the USB dongles use Realtek (RTL) chipsets, hence the name.

RTLSDRs are interesting because they allow you to scan a wide frequency and cost maybe $20 on Amazon of eBay. After getting a few, however, I started to wonder how limiting the stock antenna might be. The stock antennas which come with most RTL-SDR USB dongles are meant to pick up digital TV in Europe and are pitifully small.

RTLSDR Antenna

I wondered – would a proper antenna make a difference? The answer, in short, is yes.

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Programmatically pull Walk Score data

The other day I wanted to help get a set of Walk Score data for analysis and analytics (educational.) To their credit, Walk Score does have an API but getting a key turned out to be annoyingly difficult to me. Specifically, I used my GMail address but this website URL. Since the domain didn’t match, apparently they need to manually review my request.

Annoying. Rather than wait, it was just easier to programmatically pull Walk Score data with Python.

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