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…
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…
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?
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.
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…
To detect wheel rotations in model vehicles, we would need to install some kind of sensors on the wheels to be monitored.
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…
Continue with my previous article, let me first explain the code a little bit.
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…
I built a rather generic I2C data logger a few weeks back. As I mentioned in my earlier posts, it can be used to log data from almost any I2C slave devices with relatively little code modification.
Field strength meter is extremely useful when working with RF devices. It can be used to quickly diagnose whether a transmitter circuit is working, and can be used to detect RF signals in the environment.
Among the many commercial ISM band RF transmitter and receiver ICs, I have found that Silicon Labs‘ Si4021 (transmitter IC) and Si4311 (receiver IC) are surprisingly easy to work with. Only a few commonly available external components are needed to…