Running a task at a specified time on a Mac

Unix computers have a simple command-line feature called “at” which lets you schedule a command, or a series of commands, to be run at a specific time.    For example, if you want to download a large file in the…

Raspberry Pi Wifi Repeater

I have an old iPad which has been dropped so many times that a piece of wire fell out the side, and I think that wire was the wifi antenna.   The iPad can only connect to wifi when it’s close…

This Building Sucks  (literally)

This Building Sucks (literally)

Today the doors to the new Science Hall at SUNY New Paltz are really hard to open.   There is a howling sound as wind screams its way through the cracks between the doors, which goes away temporarily as you open…

Cosmic Watch cost estimate

Cosmic Watch: Initial Cost Estimate

CosmicWatch is a small, inexpensive, home-built (or lab-built) cosmic ray detector designed by the Laboratory for Nuclear Science at MIT.     I’ve set out to build one, and this is Episode 2 of the adventure. The claim is that “single…

Summer Solstice in Wooster Hall

Wooster Hall at SUNY New Paltz has a neat feature.   The main staircase is exactly aligned along a north-south line, and skylight windows in the ceiling were placed so that light from those windows lines up at the bottom of…

DHCP daemon on Raspberry Pi

DHCP stands for “Dynamic Host Configuration Protocol”.    The DHCP daemon is the process which assigns IP addresses to computers when they join a network, and gives them other important information about the network. Here is how to set up…

Compartment box in use

The Compartment Box Trick

Have you ever taken something apart and then put it back together and had parts left over? Me too. Sometimes it’s something I know isn’t needed, but it’s still better to get everything back in the right place.  A few…

hostapd on Raspberry Pi

The daemon hostapd is a Linux service which enables  a “host” computer to become a wifi Access Point (AP).     Thus  “host” + “AP” + “d”  (for daemon) gives the name hostapd. I originally learned to set up hostapd from …

CosmicWatch Project, Episode 1: Getting Started

CosmicWatch is an inexpensive “home-built” cosmic ray detector designed by physicists at the Laboratory for Nuclear Science at MIT.   You can read more about it here: http://cosmicwatch.lns.mit.edu/about The claim is that a college student can build one of these as a project…

Raspberry Pi Initial Configuration

Whenever I flash a new SD card with a Raspbian image, there are a number of configuration steps that are needed to tune the configuration.    This post is just to record the steps for my own future reference. It’s…

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