The Raspberry Pi: What and Why?
What is a Raspberry Pi, why you need one and what you should buy?
The new Raspberry Pi 4 (8GB) model was released earlier this year. I was able to get one for my self a few days back. The experience was really smooth. Now the device comes with 5GHz WiFi along with 2, 4K HDMI outputs. That being said, in this article, I will explain a few ways to connect to the development board along with some features it has.
Raspberry Pi’s are a series of devices that comes as single-board computers or SOCs. They are self-contained units for prototyping and development work.
This sophisticated device has many features including GPIO (General Purpose Input/Output) pins including the following tech specs.
- Broadcom BCM2711, Quad-core Cortex-A72 (ARM v8) 64-bit SoC @ 1.5GHz
- 8GB LPDDR4 SDRAM
- 2.4 GHz and 5.0 GHz WiFi and Bluetooth 5.0, BLE (Bluetooth low energy)
- Gigabit Ethernet
- 2 USB 3.0 ports and 2 USB 2.0 ports
- 2 × micro-HDMI ports (up to 4kp60 supported)
Accessing the Device
The device can be accessed like any other computer. With the 4 USB ports, you can connect a keyboard, a mouse and a screen with the micro HDMI port. In this particular model, you can go up to 2, 4K screens running at 60Hz. This will give you a full PC-like experience for development and prototyping work.
It is very easy to access as a VNC (Virtual Networking Computer) device. This enables you to stream the video output of the device over the network and use on a full-size desktop or laptop computer. This is my preferred option given that I get a full UI to interact with.
Connecting over SSH via a terminal is also possible. This provides complete freedom for those who are really good with the terminal. However, file operations, copy-pasting content and using in complex projects might be a bit difficult when you want to deal with GPIO devices as well.
VNC lets us use Raspberry Pi as a virtual machine, as long as the device is reachable through an IP address.
Yet another VM, but why? What’s so special?
Everything about the Raspberry Pi is special. Even though it interacts like a computer, it has all the low-level capabilities of a microcontroller. This means you can;
- Control motors, take data from sensors and operate relays
- Do image processing and perform robotic tasks
- Communicate with sensors using low-level protocols like;
IIC (I2C or Inter-Integrated Circuit) Communication
Digital Pins — Take HIGH LOW inputs from switches, etc.
- Process sensor data and contribute as an edge computing device
- Raspberry Pi can run as a smart home device and perform complex analytics. This includes security surveillance, implementing media servers and controlling household equipment.
- Helps with DIY projects that need complex computations and logic that cannot be done in an Arduino, yet demands to be compact in size (e.g., Gatekeeper to detect face and unlock the gate.)
Raspberry Pi offers the best of both worlds in Embedded computing; Micro-controller+Micro-computer.
Before You Buy
It is very intriguing when we talk about Raspberry Pi, but should you buy one? What should you buy?
There are several models that can perform a vast variety of computations. For example, all the models (except for computing modules) support a camera and GPIO. Hence, for starters, a Raspberry Pi Zero should be sufficient. In summary, look for the following before you buy.
- Your requirement: Image processing (high demand) or robotics (motor controlling and other low-level work). You need to justify why you might not do the same with an Arduino. Maybe you have to run a complex algorithm (spatial mapping).
- Interfacing method: Are you going to use a screen? Do you want it to be connected to the Internet at some point? What are the inbuilt ports of the board?
- Additional equipment you might need: Do you have a screen, power supply and USB hub?
There are multiple boards for you to choose depending on your experiments and prototyping requirements. Raspberry Pi 4 Model B is the latest release which comes in 3 RAM sizes as 2,4 and 8GB. It has 4 USB ports, 2 HDMI 4K outputs, 40 GPIO pins, dedicated display output and a dedicated camera interface.
Raspberry Pi 3 Model A+ board is a predecessor for the Pi 4 model. Yet it comes with all essential peripherals except for the 4K output and ethernet port.
Raspberry Pi 3 Model B+ board is slightly different from the Pi 3 Model A+. Yet, it comes with all the essential peripherals including an ethernet port.
The following images show the other similar versions of Pi including Pi 1,2 and 3. They are still in production and can be used for your purpose based on the budget and performance requirements.
The following images show the boards that are the smallest of the series. They only contain essential peripherals. For example, ethernet and full-size USB has to be sourced from an external HUB. The display output is only provided through the HDMI mini interface. It would be wiser to go for the wireless model (Zero W) which enables you to connect with VNC or SSH over the local network.
This is my first article in a series of articles that I have planned along the line of embedded systems development.
I hope you enjoyed reading this article.