A low cost embedded controller with open hardware licensing. It is supported by a range of 'shields', which are stackable daughter-boards offering a wide range of functions (e.g. LCD, CANbus, WiFi, Ethernet, Sound, SD card, etc..).
Arduino UNO: Base level board. Usually has DIL IC socket meaning chip can be upgraded/replaced. (Typ. £9 UK, £6 China)
Arduino Mega 2560: Bigger brother with more I/O and memory. (Typ. £11 UK, £9 China)
Freeduino: Arduino Diecimilia equivalent.
Here are some shields that I have used;
Wave Shield: [Adafruit v1.1 schematic]. Audio playback of WAV files from an on-board SD card. (Typ. £18 UK)
CAN-BUS Shield: [v12 DEV-10039 sparkfun schematc] CAN interface with uSD card holder for logging. (Typ. £36 UK)
Screwshield: Twin style breakout terminators [WingShield] or single board [ITead Studio] with small prototyping area. (Typ. £4 UK)
GY-521 Module: Small breakout board [schematic] using the MPU-6050 chip [InvenSense], a 3 axes Gyroscope + 3 axes Accelerometer Module. (Typ. £7 UK)
A low cost Single Board Computer running a variant of Linux. Has peripherals for things like USB inputs, HDMI video output, SD card, Ethernet port, etc..
Raspberry Pi 1 Model A: Now defunct.
Raspberry Pi 2 Model B: Second iteration. (Typ. £30 UK)
Raspberry Pi 3 Model B: Third iteration. Adds WiFi and BlueTooth. (Typ. £36 UK)
Connect to NAS drive
Add folders ... /home/pi/DiskStation/openshare
Edit drive mapping file ... sudo nano /etc/fstab
Add the mapping to the end of the file ...
//192.168.1.99/openshare /home/pi/DiskStation/openshare cifs username=?????,password=????????????,_netdev,x-systemd.automount 0 0
Save (<Ctrl>+X) ... confirm modify (Y) ... confirm filename (<Enter>)
Won't activate until next boot but cn be tested using ... sudo mount -a
Here are some Electronics links which may be of interest (with a star rating out of 5);