Smoke detectors beep when their backup battery dies, which always seems to occur in the middle of the night (at least for me.) These backup batteries are usually a small rectangular 9V. They have become popular choices for electronics projects. If you need your Arduino project to last longer than a day, this isn’t the battery you want to use. Here’s why.
The idea for AddOhms #8 has been around for quite some time. I’m always trying to find ways to explain why current limiting resistors are necessary. So while working in the shop one day, I decided to play with some LEDs and a bench-power supply. Then I decided to record what happens.
Getting started with electronics always involves a discussion of Ohm’s Law. What is this mysterious sounding law and how can you use it when building electronic projects? One the main uses for Ohm’s Law in your projects is to calculate the resistor value needed for a LED. This article takes a look at what Ohm’s Law is and how to use it with LEDs.
Soldering every circuit you build probably isn’t practical. At some point you are probably going to want to use some type of temporary method to connect different components together. One of the popular methods is using a breadboard. This simple (and cool) looking device only needs a few instructions before you can begin
It isn’t always clear what is meant by calling a device or a signal “analog” and “digital”. This AddOhms tutorial explains the difference between analog and digital by using an analogy to clocks. Old-school clocks with hands are a great example of “analog” while alarm clocks with digits as their display are an excellent example of “digital”.
The fifth episode of AddOhms tackled the difference between AC and DC. One of the things I wanted to stress in this tutorial is that even though the acronyms stand for “current”, they get used to describe voltages as well. Which, after a video on the difference between voltage and current, seemed like something that needed to be stated.
No behind the scenes for this one, just the finished video.
Fundamentally there are two types of voltage regulators: linear and switching. The names come from how they operate and how they achieve voltage regulation. Linear regulators tend to be a little cheaper to implement, but they aren’t as efficient as their more complex switching variants.
There are also some “cheap and dirty” methods that some designs use. Below is a brief description and example of each.
Digital ICs like microcontrollers, memory, and shift registers need a stable voltage source to make sure they work as expected. Most circuits are designed with a voltage regulator to accomplish this stability. In theory voltage regulators will vary their output to stay at a set voltage, regardless of how much current the load is drawing. As a load draws a little bit more current, the supply voltage will begin to sag. Conversely when the load is reduced the voltage may rise a little bit. Regulators work to eliminate, well minimize, this change.
When hooking up switches or buttons to an Arduino I/O pin, sometimes the results might appear completely random. Sometimes it will appear as though there is a delay from when the button is pressed until the state of the pin actually changes. Other times the pin’s value will seem to randomly fluctuate from HIGH to LOW. Even more maddening might be as your finger gets closer to the switch, the pin’s state changes! The fix to these problems is simple: use the Arduino Internal Pull-up Resistor. Here’s how they can fix this problem and how you can use them with an Arduino board.