Simple Current Transformer
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…
Category: Miscellaneous
Miscellaneous
2701HG-B Issues
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…
Alternative Crystal Frequency For Pinguino
After I built my first Pinguino, I decided to do some experiments on using crystals of different frequencies. By default, Pinguino uses a 20 Mhz crystal, since most of the crystals I have run at 16 Mhz I decided to…
First Pinguino Build
As I mentioned a few weeks ago, I was in the process of building tools necessary to bootstrap the hardware needed for PIC development. So far, I have built a simple parallel port programmer and have used it to flash…
Troubleshooting USB Circuit
I have built some circuits that interface with computer USB ports. On several occasions, I had built the circuits but for whatever reason they did not seem to work. Since most USB firmware is rather complex in nature, it is…
An 8-Digit 7 Segment Display
I built a 4-digit 7 segment display last year. In that design, I used four 74HC595 shift registers to drive the four individual 7 segment displays, with one for each digit. So when I wanted to build an 8-digit display,…
AT&T DSL Usage Cap
Various reports suggest that AT&T DSL usage will soon be capped at 150GB per month starting May 2. And to help users monitor their data usage, AT&T has provided an online tool for users to monitor their internet usage.
Browser Statistics
Having recently read an article on the current overall browser statistics, I decided to comb through my server log to find out what the statistics look like on my site.
Server Upgraded
My site traffic has been increasing quite a bit recently and my old Pentium III server is certainly showing its age. I had originally planed to upgrade my server hardware last year, but it didn’t quite go as planned. So…
TCA9555 Library for Arduino
TCA9555 is a 16-bit I2C I/O expander from Texas Instruments. It allows the easy addition of 16 I/O ports on any device that supports the I2C bus. This makes it attractive for expanding the number of I/O pins on the…
Building a Robotic Platform
I started this project a while ago. My intention was to adapt a toy remote controlled vehicle into a generic robotic platform, which would enable me to do some experiments with robotics. To make the platform more generic, I came…
Yet Another Flyback Transformer Project
I was looking for some parts a couple of weeks ago and came across an old TV flyback transfomer, so I thought I would build a project with it.
A Sensitive DIY Ultrasonic Range Sensor – Update
After I wrote this guide on how to build an ultrasonic range sensor from scratch, I have received many comments and questions. A couple of readers have emailed me stating that this sensor works great by itself, but somehow when…
Multiplexing the Drive Circuit
I am in the process of converting a remote controlled toy vehicle to an autonomous robotic platform. My initial thought was to just get rid of the existing circuit and add on my own. But after analyzing the control circuit…
Modified Sine Wave Generation With AVR
Modified sine wave is essentially just a pulse width modified square wave. It is a very useful waveform for power inverters. Compared with the simplest inverters with square waveform, inverters using modified sine wave can compensate the output voltage by…