After having an Xmas drink with a friend, he passed comment that I should buy a Raspberry Pi as it is something good to say on a CV that you understand them and a good learning platform for a novice.
I learnt to use an Arduino Microcontroller at University and used one in my dissertation. I understand however that a Raspberry Pi is a Microprocessor and different to the Arduino however, I was wondering are there example projects using the two products combined?
I am a telecoms engineer but have worked on SCADA systems in the past and was thinking of a domestic project for example where the Arduino could monitor a variable (undertaking the role of a remote terminal unit) and relay the information to Raspberry Pi over a network which acts as the SCADA server and presents the data on a graphical user interface.
Am I understanding the two products correctly or "barking up the wrong tree"
The Ardus (being low power) have monitoring sensors and such.
They send the data via NRF/Bluetooth to another arduino which via Serial pass the info the RPi to make a webserver with all the data shown graphically.
Digital I/O with precise timing which is often a requirement when interfacing with sensors.
Low power consumption.
Low cost.
Rapid boot up.
Physically small.
Runs for years with no maintenance.
If you are only need to monitor a switch then it comes down to cost and familiarity.
Having said that, I find looking after one Linux box is a chore. Looking after many would be a nightmare.
I have spent many hours watching a Linux box download huge amounts of automatic software updates only to fail because it has run out of disk space. You would think that a 21st century operating system would be smart enough to avoid falling into that basic trap, unfortunately it isn't.
A Raspberry Pi is a PC in a very small space. It uses the Linux operating system and can do most of the things a PC can do. Because it has an operating system it (like PCs generally) is not good at real-time activities that need precise timing. That is what the Arduino is good at.
It can make a lot of sense to combine an RPi and an Arduino if you have a project that requires a lot of programming - perhaps a web interface, or a graphic display of data. The RPi can do the heavy lifting and leave the Arduino to do the direct interfacing with sensors and outputs (relays, motor control, servos etc).
You must keep in mind that an RPi works on 3.3v and most Arduinos use 5v. The Arduino should have no problem reading 3.3v signals from the RPI but you must ensure that the Arduino's 5v output is not connected directly to an RPi 3.3.v input. Using wireless communication avoids that problem.
The Arduino Yun combines a Linux PC (not as powerful as the RPi) and a Leonardo on a single board.
