blog@Yantrajaal

Last June, I had the good fortune to visit Pangong Lake, in Ladakh, on the Indo-Tibetan border -- shown in the movie 3 Idiots -- and spent a cold and windswept night in a tent at Spangmik. The place is awesome. A huge blue-green mass of salty water -- a remnant of the seas that got trapped between India and Tibet when the former rammed into the latter and created the Himalayan range -- is surrounded by immense snowy peaks that turn golden at sunrise. But what was even more impressive was the night sky with its hundreds of stars, that we in the cities have forgotten about. Thanks to the Global Positioning System (GPS) and the Google Sky app on my smartphone, I could, for the first time in many, many years see and, more importantly, identify so many stars and constellations, including, Polaris - one of the most important stars used by ancient mariners to determine their position. Then it struck me -- in the past, stars were used to determine location but today the GPS location from my i...

A key challenge in building the "Internet of Things" is to be able to connect a device to a computer over the internet and to use as simple and lightweight an infrastructure as possible. In this post we demonstrate how a public XMPP chat server can be used to transmit data and commands from one device to another using a chat client at one end and a python "bot" sitting on the other end. We will demonstrate the ability to INSERT data into an SQLite  database, SELECT records from the same, play a variety of .wav files and execute any system commands on a "central" machine from any distant machine that supports an XMPP chat client. Before starting on this exercise, we searched the web for prior activity in this area and we came across this webpage  that suggests a similar approach for controlling devices over the internet, but the strategy explained here is simpler to code and implement. We looked for a list of public XMPP chat servers and selected ...