brainwagon

Another picture from my foamcore 4×5 camera. Roughly 150mm landscape lens, f/24, 3:50 second exposure onto Ilford Multigrade RC paper, could have probably developed a bit longer, but not bad. Inverted the print in GIMP, but no other tonal adjustment.

Ken stumbled on one of my earlier posts about DTL (diode transistor logic) and was interested enough to do some basic exploration. He reduced the DTL NAND gate to a double diode, a transistor and two resistors. Ken sent me the LTSpice and EagleCAD screen dumps that fit in about .4″ square: Pretty cool. In […]

Need to get some weather information? The website forecast.io has a nice web based service you can use up to one thousand times a day for free. I was thinking of using it for an automated sprinkler application, but just to test it, I wrote this simple chunk of python to try it out. To […]

Here are two more photos I took at last night’s camera workshop. I wanted to take something slightly more beautiful than a selfie, so I chose the Luxo statue outside the Steve Jobs building at Pixar, and some white flowers from the garden. Both were taken rather late in the day, under partly cloudy skies […]

Over the years that I’ve been interested in computer graphics and telescopes, I’ve managed to pick up a bit of knowledge about optics in general, and specifically about camera lens design. In the past, I’ve been particularly interested in old cameras and photography, and in a kind of photographic minimalism. But it has remained mostly […]

In my previous article pondering sensors for my garden, I shamefully neglected a viable and interesting choice, the JeeNode

Building my full sized quadcopter is going rather slowly (sigh) but in the mean time I picked up a little Hubsan X4 to play with. It’s cheap, and because it has a very low mass, it’s pretty hard to destroy. After more crashes than I can count, I’ve only managed to ding up one propeller […]

We’ve started a garden at our house in a pair of raised beds. I’ve been pondering about possibly creating a set of sensors to monitor the dryness of the soil in the beds as well as in the container that I have a dwarf Meyer lemon tree going in. I was trying to figure out […]

At work, we have an informal group that is interested in drones and quadcopters. Every third Thursday, we get together and fly. Today we went over to Cesar Chavez Park for a bit of flying. I was hoping that I’d have more of my own quadcopter completed, but instead I just observed Mark fly his […]

Over the last couple of years, I’ve spent a little bit of time making fixed wing aircraft from Dollar Tree foam. The results have been interesting and fun, but I’ve found that the need to find relatively large areas to fly means that it’s harder to go fly than I would like. On the other […]

This week began with a visit from Pat Hanrahan, currently a professor at Stanford and formerly at Princeton, where I was lucky enough to meet him. He came by to talk about probabilistic programming languages, which are an interesting topic that he and his students have made some interesting progress in solving difficult problems. I […]

Long time readers here should know that I have a bit of a fascination with strange, retro computing devices. While I haven’t done anything significant in this area myself, I love to see them, and at yesterday’s MakerFaire, I saw Simon’s Relay Calculating Engine. I’ll let Simon explain it to you: My own impressions: it’s […]

Over on Facebook, fellow Pixarian Arun pointed out this story on a problem I encountered in my undergraduate schooling as “The Marriage Problem”, which I also heard of as “The Secretary Problem”. The idea is that you are supposed to find a wife (or secretary) out of a list of $n$ possibles. Each one is […]

The other day I was watching the 1939 movie The Adventures of Sherlock Holmes, a rather fun film staring Basil Rathbone and Nigel Bruce. Early in the film, the maniacal Professor Moriarty (played with great zest by George Zucco) is menacing his butler Dawes for allowing one of his prize orchids to wither while he […]

Scott Haley mentioned my old Hellduino post on Facebook: a simple project that used an oscillator powered by an Arduino to send Hellschreiber, a kind of simple fax mode invented by Rudolf Hell in the 1920s. I did this mainly as a simple test, inspired by Steve Weber, KD1JV’s “temp2morse” project. But unfortunately, that page […]