Ultrasonic range finders are fun little modules that measure distance. You can use them to find the distance to an object, or to detect when something is near the sensor like a motion detector. They’re ideal for projects involving navigation, object avoidance, and home security. Because they use sound to measure distance, they work just as well in the dark as they do in the light. The ultrasonic range finde ...

To measure high levels of direct current for overload detection and protection, designers frequently use either a current-shunt resistor or a toroidal core and Hall-effect magnetic-field sensor. Both methods suffer from drawbacks. For example, measuring 20A with a 10-mΩ resistor dissipates 4W of power as waste heat. The Hall-effect sensor delivers accurate measurements and wastes little power, but it’s an e ...

As EDN's Design Ideas editor, I see a range of design submissions, from good, to not so good. A recent DI I turned down for several reasons included a high-side current sense circuit with implementation problems. This got me thinking about the different ways to accomplish current sensing on a voltage rail. At their heart, the majority of DC current sense circuits start with a resistance in a supply line (th ...

The 741 op amp is one of the most famous and popular ICs[1] with hundreds of millions sold since its invention in 1968 by famous IC designer Dave Fullagar. In this article, I look at the silicon die for the 741, discuss how it works, and explain how circuits are built from silicon. I started with a 741 op amp that was packaged in a metal can (above). Cutting the top off with a hacksaw reveals the tiny silic ...

We use an Arduino to program other ATmega without bootloader . This technique allows you to use all flash memory for code and make boards using new ATmega, cheaper than those with bootloader. The qualities that have made the success of Arduino are undoubtedly the open-source software, many libraries, a good hardware and a virtually infinite Reference that explains each possible use of the platform. But if w ...