March 14th is known in the United States as Pi Day, a celebration of the number Pi. We celebrate on March 14th because the first digits in the number Pi are 3.14 corresponding to the date 3/14. Other parts of the world represent the day prior to the month and celebrate Pi day on July 22nd. This is because the value of the ratio 22/7 which is 3.14 (to 2 decimals) matches to Pi 3.14 (also to 2 decimals). A better approximation of Pi is 355/113 which matches Pi to six decimal places. I was taught this before there were calculators and computers with the number Pi readily available.
So you may be wondering if Pi Day is in March why am I discussing it in February. I want my readers to be informed before Pi Day, and the "News" is published later in the month, and I don't want you to miss the celebration. On Pi day many pizza locations offer free or discounted pizza because pizza is typically round (except at Ledo's) and is related to Pi in that the area of the pizza is Pi times the radius of the pizza squared. So a small 14-inch diameter pizza at Three Brothers is 49* Pi or 154 square inches, and a large 16-inch pizza is 64 * Pi or 201 square inches.
The Raspberry Pi Foundation often uses Pi Day in the US to announce new additions to the Raspberry Pi family of computers. The Raspberry Pi is a collection of single board computers priced at $35 or less. The Pi Zero model is typically priced at $5. On Pi Day the Pi Zero W, a $10 computer with built-in wifi can often be found selling for $3.14 (check http://microscenter.com on March 14th).
The Raspberry Pi was designed to help people get hands-on experience learning about computers and programming on an affordable computer. Most models use a cell phone charger to provide power and use a regular USB mouse and keyboard for input. For a display, the Raspberry Pi can be connected to a TV with an HDMI input (standard for modern televisions). Network connectors and wifi are built into the recent models of Raspberry Pi, and a micro-SD memory card is used instead of a hard drive for storage. The computers all run on the Rasbian distribution of the Linux operating system and support a web browser, an office suite, and a number of programming languages. The Raspberry Pi systems are often used as Media Centers, for Retro-Gaming, and as Internet of Things (IoT) Platforms. The Raspberry Pi has tools to learn the Python programming language and additionally includes the C, C++, Java, Perl, and Mathmatica programming languages. Additional programming languages are easily added. You can install a web server, PHP, and a database like MariaDB and run web software like Word Press, Joomla, or Drupal.
The top end of the current Raspberry Pi series is the model Pi 3 B+. This model sells for $35 and includes a 4 core CPU, 4 USB 2.0 connectors, an Ethernet connector, a sound connector for speaker output, an HDMI video connector, and built-in wifi. You will need to provide a 5 volt, a 2.4 amp power-supply with a micro-USB connector (this is a typical phone charger), a USB keyboard and mouse, and an HDMI cable to connect to a TV. You may also want an optional case which can be made from a cardboard box or purchased for around $8. Look for sales on Pi Day.
Pi Alternatives and Single Board Computers
The Raspberry Pi falls into a class of computers called Single Board Computers (SBC). The advent and subsequent popularity of the Raspberry Pi led to a number of copy cats with slightly different features. These include SBCs like the Orange Pi and ODroid-C2 along with many others. Simply search online for Raspberry Pi alternatives, and you can find a large list. Many of these computers rival the Raspberry Pi in performance and features and sometimes even match or better the price. None of these have the large community of support as the Raspberry Pi.
Another SBC that is in a similar class as the Raspberry Pi but pre-dates it is the BeagleBone line of computers. BeagleBone was originally designed as open source hardware to assist people wanting to design Internet of Things projects. The BeagleBone Black is probably the most popular of the current series. It is very similar to the original Raspberry Pi but has the operating system (Arch Linux) pre-installed onboard in flash memory. The Black has been joined in recent years by several other models. The BeagleBone Blue is designed to support robotics projects with connectors for motors and servos built onto the board. The Pocket Beagle is a thumb drive size Linux computer that is ideal for smaller IoT projects. The BeagleBone Green is similar to the Black but with standard Grove connectors for easily connecting sensors.
Arduino computers are also single board computers that were designed as open source hardware to assist people wanting to design IoT projects. Unlike the other computers discussed so far, these computers do not have an operating system. Instead, software is developed on desktop or laptop computers using a special development environment and downloaded into the Arduino. This software/firmware can read values from different pins or set values on other pins.
Well, that's all for this month. Have a great Pi day and keep those cards and letters rolling.