The drive circuits for Unipolar stepper motors are usually very simple. In its simplest form, a transistor or MOSFET is used to drive each section of the windings. With this design, the control signal must be supplied programmatically to the…
I recently bought a new digital multimeter (BK 2709B) and after a couple of months’ use, I am quite satisfied with its features and performance. So I thought I would do a quick review and share my experience here.
DS28EC20 is a 20Kb 1-Wire EEPROM chip from Maxim. Like all other 1-wire devices, only a single pin is needed for both power and communication. In this blog posting, I will show you how to how to communicate with DS28EC20…
Since I do not have a DSLR camera, taking photos for my projects under normal room lighting can be quite challenging. When flash is used, the pictures often turn out to be none-uniformly lit and some components reflect quite a…
Just because you are using a true RMS multimeter does not automatically mean you should always trust the readings of your measurements. In fact, most true RMS multimeters can only offer reliable readings under certain conditions. In this post, I…
Most of the multimeters do not offer resistance measurement in the milliohm range. In most meters a typically Ohm range has an accuracy of 0.1 ohm and is too coarse for measuring small resistance. Of course, some of the high-end…
One of my computers has been unstable for quite some time now. It had been crashing and freezing up once a while in the past, but it has become noticeably worse in recent months and sometimes the computer would crash…
One of my RSA SecureID tokens had recently expired, so I decided to do a teardown to see what is inside. While there was one such teardowns posted on EETimes a few years ago, I thought it would still be…
Apress was kind enough to send me a copy of their recently released book “Arduino Robotics” a few weeks ago (ISBN13: 978-1-4302-3183-7, 628 Pages. Publication Date: July 18, 2011). So I thought I would read through and do a quick…
I recently dug up two sets of RF link transmitter/receiver modules from Sparkfun. I got these RF transmitters and receivers last year but have not had a chance to build anything with them yet. So I thought I would first…
As I mentioned a couple of weeks ago, I had been having some issues with my wireless connection at home. My suspicion was that this is an inherent issue with either 2701HG-B hardware or firmware.
The other day, I needed to measure the AC current of my water heater without having to disconnect the wiring. Typically, you would need a clamp meter to do this. Since I don’t have a clamp meter, I thought I…
It seems that the 2701HG-B gateway AT&T uses for its DSL customers has some issues with its wireless mode. I have noticed that my gateway drops connections seemingly randomly once a while but never thought it was related to the…
I wanted to be able to check my web server’s statistics periodically but did not want having to log on ever time when I wanted to do so. The simplest way to achieve this is to have the computer monitor…
Most of the recent Arduino and compatible boards use some kind of USB to UART hardware (e.g. FT232RL in Arduino Duemilanove and Atmega8U2 in the latest Arduino Uno) for interfacing with computer USB ports. Since ATmega328 has native UART support,…