My condo building has a digital video recorder (DVR) hooked up to some cameras around the building sitting in a closet. To access it when something happens, the building facility manager has to go into the closet and review the recordings, which is a pain. It’d be better to allow certain individuals (building staff, security committee, HOA board, property manager) remote access so they can review things on demand from offsite. The board inducted me into the security committee (I’m the only one on it) to solve this problem. The solution I ended up using could be useful for other purposes too, I supposed.
A few months ago, I got an email from a Sweden-based artist and teacher named Mary Coble asking if my Morse code laser post could be helpful for an art installation she was working on. She’s used Morse code in previous installations like one in Toronto where she sent coded light from a giant dome to people below who then relayed signals with flashlights. As a part of a new project, she wanted people to be able to enter protest chants into a website and then have a system convert the message to code and flash a light in a gallery window. Did I want to help? You bet I did!
I got super excited about the prospect of helping with this and knew that with a combination of things I’ve used before it would be really doable. The plan was to have a webserver accept messages from a form and transmit them to a Raspberry Pi (cheap mini-computer), which would then flip pins on a relay to blink the light, like this:
After many emails and some ups and downs, everything worked! This really feels like how the internet is supposed to work.
Thanks entirely to the efforts of local climate-related organizations in Seattle, I’ve now spoken at a handful of book stores, breweries, universities, and even Town Hall on climate and energy. Last week, I was honored to be on one such panel at a brewery in Ballard alongside Univ. of Washington oceanographer LuAnne Thompson and Governor Inslee’s senior climate policy advisor, Reed Schuler. My role was to provide background information on the human relationship with energy: what we’ve used in the past, what we’re using today, and what our low-carbon options are moving forward. I touched on progress and challenges with intermittency, hydro, and nuclear. This post summarizes and expands upon these topics.
Energy is a replacement for the labor of human beings
The first part of my talk was easy. I threw up my favorite slides demonstrating how energy improves quality of life by replacing human labor. Between construction, farming, heating, water, laundry, and travel it’s a pretty easy case to make.
So in the continuing saga with my mom’s home-automated furnace, it got extra cold recently and I noticed it wasn’t getting up to temperature in time for her to wake up. I figured I could come up with a formula to compute the time needed to come to temperature and turn on the furnace at a dynamic time in the morning so it’d be just right.
I’m becoming convinced that Jeremy Howard is right to predict that deep learning is going to be “more important and more transformational than the internet.” If you don’t know who Jeremy Howard is, he’s part of the duo behind fast.ai free and high-quality deep learning course series, which is dedicated to making deep learning accessible to everyone.
Deep learning takes advantage of certain graphics processors (GPUs) to be efficient. If you take the course, it’s recommended that you sign up for an Amazon Web Services machine with an appropriate GPU so you can just run the provided setup scripts and be on your way learning deep learning. But you may want to try to get everything set up on your own machine if you happen to have one. I just built a small server and added a modest GPU just for this purpose so I figured I’d give it a whirl. This is how I did it.
You know how some airplanes can get their gas filled up while in the air by tankers (aerial refueling)? And how ships at sea do this too (underway replenishment)? And you know how self-driving cars and trucks are taking over everything soon? Well there’s going to be a need for mobile gas stations on the road.
Think of it! Long-haul trucking will want to go non-stop, and to do so there can be little sections of road where a tanker truck drives alongside the main truck, hooks up a hose, and refuels it for 10 minutes while everyone’s moving. Then the self-driving truck carries on and the tanker truck crosses the road, services a truck going in the other direction, and repeats until it eventually has to fill up from a bigger tank nearby.
Another manifestation is a thing on a long rail that refuels you as you drive alongside it. The hose could be on a sliding coupler that maintains a hermetic seal.
This could happen with passenger vehicles too. Presumably people will hop in their cars at night and expect to wake up in Florida the next day so they’re going to need automated gas refilling as well. Ideally this would be underway but I guess if gas stations could just fill up cars that roll in that’d be acceptable too. It will be more comfortable and less disturbing if this happens while on the road though.
That’ll be a billion dollar industry soon. If they’re electric cars, these will be charging stations instead of refueling stations.
I decided I wanted a network-attached storage (NAS) server because I needed some central and safe place to put all my big files. I’ve been using more and more hard drive space because I’ve been taking photos in RAW and collecting more digital video (camera, dashcam, digitized home videos from the 1990s, and drone). I also just enjoy fiddling with servers and stuff and thought I could use a home server for a variety of other things. My raspberry pi has been doing well for my home automation but a bigger server might make it faster. I’m trying to learn Blender and have been eyeing a Machine Learning course. Both of those require a nice modern GPU. Finally, I just enjoy learning things about computers.
On June 19th, my little sister sent me Annie Dillard’s essay about her experience viewing the 1979 total solar eclipse and stated that we were going to go see it in Oregon. She said: “This essay has made going to the Eclipse non-negotiable in my mind.” I had been moderately interested but somehow the essay made it sound way cooler that I had previously envisioned and so I got excited about it. There was already hype about how bad traffic would be down in Oregon, but she said she had been thinking about dispersed camping in Malheur National Forest. I looked at a map and it looked pretty good.
I read that it’s Goodnight Moon’s 70th birthday today. I have it on the bookshelf so I pulled it down to celebrate. Going through it after so many years led me to discover some nice hidden gems worked into the illustrations that I had never noticed before (like when I was 5). I’m sure parents everywhere notice after reading this hundreds of times, but it was fun for me to discover them.
The story takes place from 7pm to 8:10pm
The two clocks in the room are synchronized. They start at 7pm and end at 8:10pm. Each time the room is shown it’s 10 minutes later. I think everyone notices that the moon rises in each scene as well.
I’m trying to learn ways to minimize my reliance upon large companies for handling my day-to-day personal data. So I figured calendar and contacts should be on my list of things to self-host. This post is about how I migrated all my Google calendars and phone contacts to my own server without losing any features I was using. I’m doing this mostly for fun.
I got a few Amcrest Wifi security cameras for my mom’s house at her request. They’re pretty nice overall (My only complaint is that the web-interface doesn’t fully support Linux). I set one up to save a jpg snapshot to memory every minute and then flew across the country. When I wanted to access them, I couldn’t just put the SD-card in a computer or anything, and clicking all 14,000 of them seemed like a pain, so I decided to figure out how to get them with a Python script.
There are some digital levels on the market that are really nice tools to have for a variety of purposes. I grabbed a DXL360 and am really happy with it so far. When I wanted to do an angle vs. time calibration measurement of my Barn Door Startracker over 10s of minutes, I really wanted to get the data from the level into a computer so I could plot and process it a bit.
The level has a USB port but the manual suggests that an optional attachment is required to get it into a computer, at least for this model. However, the manual also states that data comes out of it in RS232 format. I bet I could read that data with some more generic equipment that I have sitting around. And it turned out to be easy. This post shows how I did it.
I like to mix hobbies, so naturally I’ve been eying astrophotography for a while. I’ve taken a time-lapse here and a moon picture there but, inspired by the folks over at /r/astrophotography, I wanted to take it to the next level. Since the Earth is spinning, any long exposure of the night sky has star trails, so you have to make your camera counter-spin if you want clear shots. In this post, you can read about how I made a simple barn door sky tracker to do this.
Barn door sky trackers have been made at home by lots of people for a long time. There are a variety of designs with different levels of complexity and precision required. I thought I’d make the simplest-to-construct one, a Haig mount. To correct he tangent error, I decided to use a cheap microcontroller (MCU) and have it speed up appropriately via software. Fun!
The math behind this is fun mostly because it’s straight out of high school and you finally at long last get to use it. Here’s the basic design:
I use SpamAssassin on my e-mail server to flag spam messages that come to my addresses. It uses a series of checks on each message and determines a Spam Score. If the Score is above a user-defined threshold, it adds a header that says that it is spam. Then dovecot files it away into a spam folder instead of my inbox. It does a pretty good job but requires tuning sometimes. I wanted to see if I could change my threshold from the default (5.0) without getting too many false positives or negatives. To do that, I’d have to collect some stats from my messages.
A year ago, my friend Laura was wishing that email providers could do some tone filtering and reject messages that are too mean. Since I run my own email server, I thought it might be simple to set something like that up easily. Turns out, it’s not that hard, but it wasn’t exactly trivial to figure out.
I run have postfix running to receive messages from the internet. It passes them through SpamAssassin, which inspects the messages and adds a few headers that indicate whether or not it’s spam. Then it passes them on to dovecot , which stores the messages in mailboxes and then tells with my email client, Thunderbird, that I’ve got mail. I like this setup because I feel like I have a bit more control over my data. Besides, it’s fun!
The original request is here shown below. I figure, if I could just have the message go through a second filter after it goes through spamassassin, I could make it a custom script that counts swear words.
I got one of those RGB LED matrix things for my birthday and wasn’t sure what to do with it. Then I found this awesome library which has Python bindings and can control it nicely even from a Raspberry Pi. Conveniently I had a spare Raspberry Pi 1 B+ sitting around so I hooked it up. After playing around for a while, I got the demos working.
UPDATE: Full documentation of infopanel is now available.
- Get data directly from a MQTT broker for getting live data (e.g. travel times in traffic, weather conditions) and for command and control. This allows me to connect the screen to my home-assistant home automation system.
- Assemble various built-in elements like giraffes, animated text, rainbow text, pictures, animated gifs into various scenes that rotate through on the screen to display the information in various fun and/or useful ways.
- There are Temperature and Duration sprites that you can define high and low values of so they’re red when they’re bad and green when they’re good, and anywhere in between.
You can set the scenes to be just random or you can control them through MQTT.
It’s intended to be very configurable but since it’s brand new some extra development is needed to make everything perfect. Send in your ideas and requests and code changes!
A relatively complete example configuration file is in the repo. That demonstrates using MQTT, connecting MQTT topics to various sprites, building your own frames of animation by hand, and adding in gifs and images from file paths. Note that you have to set an environmental variable or two to get the fonts right and whatnot.
Note: This is a thowback post, revitalized from the old partofthething.com where it was posted by me in like, 2004. I took out most last names.
My car is the ultimate car ever. It’s the greatest thing on Earth. No, really. It is. Sure, sure it’s old but that’s not what matters anymore. It’s the past that counts…and the stereo system. I grew up in this car. Yes sir I did. I always sat in the back right seat driving all over the place since I was seven years old. Usually Tom Petty was playing. you see, it used to be my mom’s car. When she got a new one, it became my sister’s car. And then, it became my car.
I have a website or two and sometime wish I could get notifications whenever someone visited them, just for fun. Well I did it, and now I can get beeps in my home whenever anyone visits. It’s kind of cool to hear it go off, though normally it will be annoying, so we need a switch for it.
Collecting information about our surroundings, analyzing it to make conclusions, and then performing actions based on those conclusions is the definition of life itself. Organisms generally care most about their food source, dangerous strangers nearby, environmental changes, and family planning. For example, the rabbit pays attention to nearby gardens, the closest rival warren, any nearby foxes, human constructions, and potential lover rabbits*. The human was concerned with roughly the same things for years immeasurable, but since the Bronze Age, as we spread out globally and invented neat technologies, things became a bit more complex.
I learned on reddit the other day about the sudo “insults” capability where it throws shade at you when you mistype the password. I configured it everywhere I could, but I wanted more, so I came across
$ fortune | cowsay / SHIFT TO THE LEFT! SHIFT TO THE RIGHT! \ \ POP UP, PUSH DOWN, BYTE, BYTE, BYTE! / ---------------------------------------- \ ^__^ \ (oo)\_______ (__)\ )\/\ ||----w | || ||
Needless to say… wow.