After going through some of the tutorials on Arduino’s site, I really started to appreciate what a powerful platform Arduino really is. A lot of seemingly complex software/hardware interactions can be made quite easy with relatively few components and little coding. As one of my first Arduino based projects, I built a simple power inverter driven by Arduino.
Read more…
When I first started interfacing electronics with computers back in the early 90’s my hardware choice was an ISA AD/DA card. So when I wanted to experiment with some physical computing stuff recently, I thought of getting an AD/DA card that can be plugged into either a PCI or a PCI Express slot.
Read more…
Using PC’s parallel port is a convenient way to control a stepper motor. For unipolar stepper motors, up to two motors can be controlled with the 8bit data line.
Read more…
Using DTR (data terminal ready) and RTS (request to send) pins of a PC serial port (RS-232) without actually using the serial data pins, we can interface at least two relay devices with a computer. Windmeadow Labs has an excellent article on how to achieve this using a bipolar transistor (BJT). Here I will show you a similar relay control circuit built using an opto-isolator and a MOSFET.
Read more…
One of my older CRT TVs does not have a built-in degauss button and after sitting in the corner of the basement for a couple of years, it somehow got magnetized pretty badly. The top two-thirds became totally disclorored with the “rainbow” effect.
Read more…
A touch sensitive on/off switch can be made with a single MOSFET. The following schematics illustrate such a switch using only a power MOSFET (IRFZ22).
Read more…
When Google Chrome beta for Windows was first released last September, I tested it briefly on a Windows XP box and was quite impressed by its speed and simplistic user interface.
Read more…
Hall effect sensors can be found in many common household gadgets. Most brushless DC motors for instance, like those used in computer cooling fans, contain Hall effect sensors in the driving circuits.
Read more…
Sometimes a group of concurrently running threads may need to rendezvous at a certain point in time before they can further proceed. This situation commonly arises in areas like event simulation, where the events are synchronized via a clock event (see illustration below):
Read more…
A palindromic prime (palprime) is a prime number that is also palindromic. So out of curiosity I wrote a simple program a few days ago that can find the palindromic numbers within a given range. Here is the code in C++:
Read more…
Many of you may still remember the capacitor plague that caused massive motherboard failures back in the early 2000s. While the practice of using cheap and unreliable electrolytic capacitors in computer components has largely died down nowadays, it seems that the issue has cropped up elsewhere.
Read more…
Karmic Koala was released into the wild last Thursday, so naturally I was going to upgrade my desktop installations at home. In this past I had been doing fresh installs whenever there was a new release, since there might be some issues with the new Ext4 file system, I decided to upgrade my current 9.04 installation in place and perform a fresh installation when the Ext4 file system stabilizes.
Read more…