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.
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.
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.
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.
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! /
Oh this is exciting! I’ve been trying to figure out how to get motion events from my IP camera into my home-assistant instance running on my Raspberry Pi, and I just did a successful test! It works! Hooray. Briefly, I set up an email server on the Pi, have the camera email the Pi, have the email server trigger a script which parses the email for key words and sends MQTT signals as appropriate, at which point the home-assistant MQTT client sees them and triggers automations (like blinking a light to scare people off). Here’s how I did it.
You may have seen my earlier post about my new home automation setup. Well I just upgraded it! I just finished testing out a new infrared remote control send and receive capability and it is pure awesome. Here’s what I can do now from within home-assistant:
Turn on and off my new DeLonghi portable air conditioner from Costco, and set the temperature to whatever
Turn on and off the TV and press any buttons from its remote control
Turn on and off the stereo and virtually press any buttons from its remote control (which I never even had!)
Use an old random blueray remote control to set scenes, turn lights on and off, etc. (basically do anything under home-assistant’s control)
This post is about how I did it on my Raspberry Pi.
I went over to my friend’s house last night to help get home-assistant on a Raspberry Pi working for his z-wave door sensors and siren. The Ecotech sensor showed up fine but the Aeotech recessed one (Recessed Door Sensor Gen5 , ZW089-A) did not show up by default. After poking around in the logs for a while, we realized that it was sending BASIC_SET command classes instead of BinarySensor commands. Apparently (I thought I had fixed this already), home-assistant doesn’t recognize the BASIC_SET commands just yet. But looking at the config file for this device, we discovered that config item 121 changes which kind of report this sensor sends: Continue reading Using an Aeotech recessed door sensor in home-assistant
In this post, we’ll take a brief measurement of regular old FM radio stations and try to determine where we are. It’s like a GPS but with local FM transmitters instead of satellites. I did this just for fun. I wonder if it could be used for indoor location and stuff? It is nowhere near as accurate as GPS. But whatever.
Reading FM radio signal power
The first step is to get a reading of all the nearby radio stations. I used gnuradio and a HackRF One software defined radio. A simple flow-chart that takes the FFT and dumps it to a file is all I needed. I had to throttle the I/O or else my computer would freeze. I used 16M sample rate to have as wide a bandwidth as possible.
The file sink saves the FFT results in 4-byte integers and just has one 1024-length vector after the other. In a few seconds, I had a 50 MB of data. I did all the post-processing in an external Python script.
I’ve always dreamed of having a “smart-home.” There’s just something cool about being able to flip switches and read sensors and have a program turn a light on when you open the door, but only if it’s dark. This post is about home automation.
Sending and receiving text with Morse code light pulses across the room (or to your neighbor) is a fun and cheap project you can do on a Raspberry Pi or Arduino or any other microcontroller. This post explains how I did it, and how you can do it too.
The hardware is simple and cheap. Here’s my parts list:
Raspberry Pi B+ as the controller. This does the sending, receiving, and signal processing.
Photoresistor – Just a little guy that has variable resistance based on how much light is hitting it
A 220 Ohm resistor – to make a voltage divider with the photoresistor for reading the input signal
MCP3008 10-bit Analog-to-Digital Converter (ADC) – Since the RPi doesn’t come with an ADC, this is required for converting analog voltage from the photoresistor into a signal I can process on the RPi.
Laser module – to transmit with laser light. I got one from sunfounder.com for like 3 bucks.
You can learn how to use the ADC at this Adafruit tutorial. I decided to talk to the ADC with the RPi’s hardware SPI interface, which I had already enabled. I wanted to be able to go very fast. (You can alternatively do SPI off of GPIO ports with software, if you prefer.) The laser just hooks directly between a GPIO and +5V. Here’s the layout:
Sensors are fun!I wanted to keep an eye on the temperature of one of my home physics projects and realized I needed a thermocouple and a convenient way to read it. This post is about how I got one and wrote a Python program to send the data from a Raspberry PI over the network to my laptop, which plots the results in real time.
I bought a K-type thermocouple for several dollars that ranges from -100°C to 500°C. The Seebeck effect that makes it work only gives microvolts per degree so I needed a good amplifier for it. And since I wanted to read it on a Raspberry PI (which only has digital inputs), I’d need an analog-to-digital converter (ADC). Conveniently, the MAX31855 does amplification and ADC and is like $15, so I got one. Sweet. There’s even a Python library for it that makes it easy to access. Double-sweet.