May 1, 2011, 3:22 pm
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 thought about using the same design with eight 74HC595s at first. But it seemed that the soldering would be a lot more challenging on the prototype board as there will be 8 chips and 64 resistors to solder. Continue reading ‘An 8-Digit 7 Segment Display’ »
March 27, 2011, 7:32 pm
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. Continue reading ‘Wake On … IR’ »
March 20, 2011, 4:40 pm
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 two fully differential input channels while AD7706 has three pseudo differential input channels. Continue reading ‘AD7705/AD7706 Library’ »
March 11, 2011, 9:35 pm
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 I2C support or can be pre-programmed and used in standalone applications as digital thermostats. Continue reading ‘Interfacing DS7505’ »
March 5, 2011, 9:11 pm
TCA9555 is a 16-bit I2C I/O expander from Taxes 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 standard Arduino platform using ATmega328. Up to eight TCA9555′s can be used on the same I2C bus and thus allowing up to an additional 128 digital pins to be added. Continue reading ‘TCA9555 Library for Arduino’ »
February 26, 2011, 4:40 pm
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 pretty low. Building a very basic arbitrary waveform generator is actually quite simple using a digital-to-analog converter (DAC) chip and a microcontroller (MCU). Here I will show you one such waveform generator using Linear Technology‘s LTC1450 DAC and ATmega328 programmed with Arduino libraries. Continue reading ‘Arbitrary Waveform Generation with Arduino’ »
January 22, 2011, 9:43 pm
I needed some ultrasonic range finders for my project. But most of the commercial sensors like Parallax’s PING sensor and other similar products are quite expensive, especially if multiple units are needed. So I thought why not building it myself? Continue reading ‘A Sensitive DIY Ultrasonic Range Sensor’ »
January 16, 2011, 4:02 pm
It is fairly simple to build a digital metronome using an ATmega328 AVR chip and some minimal programming using the Arduino libraries. The main challenge though is to display the tempo information conveniently. Continue reading ‘Digital Metronome’ »
January 7, 2011, 9:04 pm
In my previous post, I showed a simple optical encoder circuit that is TTL compatible. The main drawback of the circuit is that it does not provide enough resolution since the encoder is only triggered when the mounted mirror is aligned. Continue reading ‘Simple Optical Encoder For Wheel Rotation Detection – II’ »
January 1, 2011, 10:28 pm
To detect wheel rotations in model vehicles, we would need to install some kind of sensors on the wheels to be monitored. Continue reading ‘Simple Optical Encoder For Wheel Rotation Detection – I’ »
December 26, 2010, 3:14 pm
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 simply changing the pulse width (duty cycle) of the waveform. Continue reading ‘Modified Sine Wave Generation With AVR’ »
December 8, 2010, 9:02 pm
Tags:
74VHC4040,
AD5235,
Arduino,
Atmega328P,
C++,
LTC6905,
RF,
Signal Generator,
TS5A23159,
Wide Band Category:
AVR/Arduino,
Miscellaneous |
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December 2, 2010, 8:21 pm
A signal generator can come in handy when working with digital and analog circuits. While most commercial grade signal generators offer more than just outputting a sinusoidal waveform, they are quite pricey for casual use. In this article, I will show you a simple wide band signal generator that is built around a Linear Technology’s LTC6905 Silicon Oscillator, which is can generate frequencies from roughly 17MHz to 170MHz. Along with a FairChild Semiconductor’s 74VHC4040 12-stage high speed binary counter, this signal generator is capable of generating precise frequencies from as low as 4KHz all the way through the ranges of LTC6905. Continue reading ‘4KHz-170MHz Wide Band RF Signal Generator – I’ »
October 16, 2010, 12:41 pm
I have been thinking about building an LC meter for a while since I do not have a multimeter that is capable of measuring inductance and while the multimeters I have can measure capacitance, they are not able to give accurate readings for small capacitance in the range of several pF’s. Continue reading ‘AVR LC Meter With Frequency Measurement’ »
September 18, 2010, 7:27 pm
The official Arduino Duemilanove board is an excellent tool for prototyping. For most of the users, it is a very solid platform for various MCU experiment circuits given the number of readily-made shields available. Continue reading ‘ZIF Arduino Prototyping Board’ »