A very little known feature of EAGLE is the ability to type commands instead of clicking an icon on the toolbar. This can come in handy when trying to perform multiple actions like selecting a group and moving it to a different part of the schematic. For me, since I use OSX trying to use function keys in EAGLE can be more cumbersome than typing a few letters.
The quick answer to “How do you reset millis()” is: You Don’t! And here’s why: if you did, it would potentially break most libraries and functions that rely on it. Generally the reason people want to reset it, is that they are concerned about rollover. Instead of focusing on resetting millis(), here is how to use it correctly.
Avoiding rollover and checking how much time as passed is done in a single line:
if ((unsigned long)(millis() - previousMillis) >= interval)That single line of code is all that is really needed, to avoid rollover! Pretty simple, huh? So let’s go into more detail about how this works and what each of those variables does.
When getting started with the Arduino, the shear number of board options can be intimidating. While the variety is a great option, it can be daunting to a new user. Many people are afraid of selecting the wrong board, or their budget doesn’t allow for buying multiple boards. Just looking at the “official” boards listed on the Arduino.cc site, there are 14+ different Arduino board types to consider. Then there are a variety of 3rd-party boards with their own uniqueness.
This publicly editable Arduino Comparison Table is a one-stop place to compare key features of Arduino boards, such as Input Voltage, I/O Pins Available, and Connectivity options. Feel free to update information, make changes, or add new boards.
Visit the Google Docs Spreadsheet to use filters and sort by the various parameters.
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.
Open Source Hardware (OSH) means not only releasing devices, but all of the documentation associated with them. For some projects, this may include the actual CAD files used to produce the device. For example, the Arduino team produces not only schematics but the Eagle PCB CAD files for each of their boards. The great thing about such disclosure is that one can easily tweak the existing design for their own purposes. The downside is that nearly anyone can submit the exact same files to their own production house and have immediate clones.
Even when some people choose to do this, as have some eBay (and now Amazon) sellers, differences crop up from “real” boards and the clones (aka “fakes”). Click on the above photo for a Flickr-based “spot the differences” game!
