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…
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…
I mentioned in one of my previous posts that I decided to give PIC family MCUs a spin after having been working with AVR chips for sometime. From a pure technological stand point PIC programming and AVR programming are not…
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…
I built a digital thermometer a couple of weeks ago. This thermometer uses an LM19 sensor calibrated for measuring a wide temperature range (-55 – 130 Celsius, -67 – 266 Fahrenheit) for outdoor temperature measurement and an SHT21 digital thermometer…
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,…
I have been using AVR for quite a while but have never used any PIC micro-controllers from Microchip. It seems that both AVR and PIC camps have very strong preferences towards their own technologies and there are lots of AVR…
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.
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.
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…
One of my old computers is used as a file backup server in my basement office. It is kept off most of the time and only powered on when I needed to sync up files.
AD7705 and AD7706 are two 16-bit Sigma Delta ADCs. Equipped with on-chip digital filters and programmable gain front ends, these chips are ideal for low frequency multi-channel signal measurements. The main difference between AD7705 and AD7706 is that AD7705 has…
The DS7505 digital thermometer and thermostat is a very versatile temperature sensor. It offers 9 to 12-bit digital temperature readings between -55 and +125 Celsius with an accuracy of 0.5 degree. It can be used with any MCUs that has…
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…
Arbitrary waveform generators come in handy when troubleshooting digital and analog circuits. Most commercial arbitrary waveform generators are very expensive due to the functionality and very high bandwidth they offer. But for typical uses among hobbyists, the requirements are generally…