**Pi Day - March 14th**

March 14th is Pi Day. Pi is the number that represents the ratio of a circle’s circumference to its diameter. In other words, the distance around the outside of a circle divided by the distance of a straight line through the center of the circle. This number is close to 3.14159 or 355/113. Pi is an irrational number which also means there is no end to the number of digits to the right of the decimal point. Pi is important in most mathematics including geometry, trigonometry, and calculus. Pi day is observed on March 14th since 3.14 approximates the value of Pi. It is typical to find discounted pizza and various fruit pies on Pi Day. Also Pi Day is traditional; day for the Raspberry Pi organization to release new computers and for the computers to go on sale.

**Raspberry Pi Foundation**

The Raspberry Pi Foundation is a charitable group formed by people from the University of Cambridge in England who were concerned about the quality of students entering into computer science programs. It seems that children who grew up with inexpensive home computers like the Commodore 64, Timex Sinclair, Acorn computers were arriving at college with a better background than today’s students. The thinking was that a solution could be had by creating a small inexpensive computer that could be connected to a TV and included a built-in environment to learn programming and other Science and Technology skills. This computer had to be inexpensive enough for everyone to afford and yet powerful enough for people to learn how to program in languages like Python, C, C++, and Java. The original Raspberry Pi provided the bare computer board for $35. It needed an SD memory card, any old cell phone charger with a micro-USB connector for power, a USB keyboard and mouse like to ones common to today’s desktop computers and a standard cable to connect to a TV. It included 2 USB ports an Ethernet port, a connector for speakers, and both HDMI for modern TVs and a composite video port for older TVs. It wasn’t too hard to find all of the extra pieces needed to make a fully working computer in the neighborhood trash. Over the years the Raspberry Pi Foundation has released many accessories for the Pi computers including cameras, video screens, cases, official keyboards, and mice. These are not needed to use the computer, but the sales help fund the charity. They have also released many different computers that range in price from $4 to $80 to address the growing needs of the Raspberry Pi communities.

**New Raspberry Pi Computers**

I have written several columns over the years talking about the Raspberry Pi computers. The Raspberry Pi Foundation releases new computers and gear fairly regularly but there has been a lot new since I last wrote about the Pi so I thought I would bring you up to date. At the beginning of 2020 they released the PI 4 with 8 Gigabytes of RAM for $79. They also discontinued the 1 Gigabyte Pi 4 model and lowered the price of the 2 Gigabyte Pi 4 model to $35. There is also a 4 Gigabyte model for $49. The Pi 4 models all include a quad-core CPU, Wi-Fi and Bluetooth capability, a gigabit Ethernet port, two USB 3 ports, two USB 2 ports and two micro-HDMI connectors allowing connection to two monitors or TVs at one time. They still use an inexpensive SD memory card for data storage but can now also boot from any USB drive.

At the end of last year they released the new Pi 400 kit. This a complete computer built into a keyboard with all of the capabilituies of the 4 Gigabyte Pi 4. The kit includes everything needed to use the computer except the TV or monitor and sells locally for $100. The software with every Pi includes eveything we have discussed plus the Libre Office office suite, Mathmatica, a powerful math package, and the Chromium web browser.

The latest addition to the Pi family is the Pi Pico. The Pico is not a full computer running the Linux Operating System like the other Pi computers. It is a micro-controller with limited resources but more inputs an outputs. These are great for building things like robots and weather stations. The Pico is an alternative the Arduino boards that are often used for these types of projects. The Pico sells locally for about $4.

**Older Pi Computers amd Wrap Up**

Many of the older Pi computer models are still around as well. The Pi model B3+ can often be found for $29 and the Pi-0W with built in Wi-Fi can be bought for $10. If you don’t need Wi-Fi the Pi-0 is still normally priced at $5. The Pi-0 computers are a great solution for small computer-controlled projects.

I always look forward to Pi Day because math is cool, and the Pi computers typically go on sale. Have a great Pi Day and I will be back in March to talk about my next technology topic.

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