“Probability of match, 67.34%.”

The engineer sighed, and shuffled across the room in his tiny apartment to pour another cup of strong, black coffee. He was exhausted. The apartment was overly warm, and a fan in one of the dozens of desktop computers buzzed loudly. He hadn’t been able to track the damn thing down. The place had seen better days — the paint on one wall bubbled near the ceiling from an old leak, and it smelled faintly of mold. He didn’t care.

When he and his wife had first gotten the news, he had channeled his shock into…

I recently began playing with ROS in simulation, and am really enjoying it. I want a platform that I can use for experiments, particularly learning to configure a physical robot for SLAM and navigation. If you are not familiar with ROS, or have been intimidated by the steep learning curve, you might want to give my introductory article a look first.

I stumbled on the Weddell 2 ROS Robot by user pokpong on Thingiverse, and was very impressed. It was very close to what I was after. I couldn’t source the motors the original device used, so I made a…

By now, you’ve likely spent a ton of time on Zoom/Teams calls for work, family gatherings, some time with friends, and school. Trying to gather a bunch of folks around a single laptop for dinner or a birthday party is challenging. Holding academic classes on a small screen is not ideal, especially with younger kids. We tried ballet class via video conferencing, with a laptop on a TV tray, and it was… sort of OK. I decided it was time to set up our TV for video conferencing and remote classwork. It’s easy to do, and it doesn’t have to…

I present here the full code of my first crypto trading bot, in the hopes that it might be useful to others. The bot uses robin_stock, pandas, and ta-lib to make automated trades on RobinHood.

First, let’s make sure we’re clear on something. Cryptocurrency investing is risky. Doing it using a computer program is even riskier. Doing it with code you didn’t write, or don’t fully understand, is a _terrible_ idea. What you do with this code is entirely up to you, and any risks you take are your own. It’s intended to be educational and comes with absolutely no…

There are some subtle gotchas… save yourself some time!

I recently wrote my first cryptocurrency trading bot. I started by playing with historical prices for Bitcoin at ten minute intervals — I loaded them into Python Pandas dataframes and ran some simulations, buying low and selling high. It looked great! The code was simple, too — I figured it wouldn’t take more than a few hours to bolt on some robin_stock functions and go to town. I was wrong. Here’s what I learned as I went — perhaps it will save you some time.

Trading in simulation is simpler than…

This heat map shows the progression of the COVID-19 pandemic in the United States over time. The map is read from left to right, and color coded to show the relative numbers of new cases by state, adjusted for population.

This visualization was inspired by a similar heat map that I saw on a discussion forum thread. I could never locate the source, as it was only a pasted image with no link. The original version was also crafted to make a political point, separating states by predominate party affiliation, which I was not as interested in. …

There comes a time in every robot builder’s life when they start thinking about building something... epic. Maybe you’ve built a couple of simple Arduino bots that run around a room and avoid obstacles, or followed a track on the floor. They are terrific fun, and you’ve learned a lot, but you’d like to do something more complex, with some image processing, or network control, or one of those inexpensive LIDAR sensors you’ve seen. Do you have to write all that stuff from the ground up? Where do you even start?

I’d recommend you take the time to learn the…

Overview

Hobby robotics is a fascinating mix of different skill sets — a bit of electronics, a dash of mechanics, some code. You can go as deep as you want — open source projects make advanced projects like vision or Simultaneous Localization and Mapping (SLAM) easier to implement than ever before. There are even free simulators if you want to play with algorithms and aren’t interested in building hardware. It’s a terrific playground for DIY enthusiasts, programmers, and budding engineers.

Having built several simple Arduino robots with a few sensors, I wanted a platform that I could use to experiment…