Songle Relay

These power relays are great for simple control of turning power on and off to a device.  The tricky part is finding any information on exactly how the pin mapping is setup.

Rise and Smile Project

The original goal of this project was to provide a way to send messages to my kids before I went to work since I go in very early and don't see them in the morning.  This simple device can receive messages from a computer or phone over a local LAN, and displays the text on its screen.

Adafruit 4x3 Phone Matrix Keypad (with I2C)

This entry details the setup for using the Adafruit Phone style 4x3 Matrix Keypad.  I liked the way this one looked, even though there wasn't good documentation how to use it.  I wanted to prevent utilizing so many digital pins, so I went the I2C route with the PCF8574 board.

Arduino IDE Paths

When developing in the Arduino IDE there are a number of paths for where specific examples or libraries are stored, or can be stored for easy access.

By preferences set in the IDE you can set where your own generated sketches are.

From here, an internal libraries folder is created.  Any files placed within that path are considered part of the system path, and therefore files can be included with the <*.h> syntax.

There are also the following:

• C:\Program Files (x86)\Arduino\libraries
• C:\Users\[username]\AppData\Local\Arduino15

Push Button (non latch)

When adding non latching push buttons to an arduino, it's not obvious from the button itself how the signal flows through its prongs.  In the image below, top two prongs are shorted, and the bottom two are shorted.  The switch essentially joins the top to the bottom when pressed.

Traditional methods of wiring for these buttons are as shown.  A pull-down resistor method on the left, and a pull-up resistor method on the right.

I2C Backpack for LCD

This link more than adequately covers the setup and execution of using a PCF8574 backpack with a standard LCD https://www.instructables.com/id/Using-PCF8574-backpacks-with-LCD-modules-and-Ardui/

The beauty of the backpack is that it reduces all the digital IO needed to run an LCD down to two digital pins!

I have some caveats to identify when working with the NodeMcu ESP8266

NodeMCU - ES8266 Board

The NodeMCU ES8266 board is probably the most affordable method making use of the Arduino IDE to have WiFi capability in a microcontroller package.  It is as simple to use as an Arduino, although I have found that there is a great limit in using it like an Arduino in terms of what pins are available.