For details on programming Arduino compatible boards, see Arduino Programming.
See the dedicated page, Raspberry Pi.
For example, this 64×8 RGB LED matrix from Amazon: BTF-LIGHTING WS2812B ECO RGB Alloy Wires 5050SMD Individual Addressable 8X32 256 Pixels LED Matrix Flexible FPCB Full Color Works with K-1000C,SP107E,etc Controllers Image Video Text Display DC5V.
The `WS2811` and `WS2812` are common in various LED strips. There are multiple libraries that allow you to control each LED.
Each LED consumes about 20ma per color, so 60mA at full brightness. For a 256 pixel strip, that is 15,360mA.
Here is another tutorial on using WS2812 LEDs: https://howtomechatronics.com/tutorials/arduino/how-to-control-ws2812b-individually-addressable-leds-using-arduino/
These power relays let you switch high voltage power (110V AC/250V AC) using low power logic (5V). This lets you control household appliances.
Wiring diagram: https://www.circuitbasics.com/setting-up-a-5v-relay-on-the-arduino/ There are two sides, one side with the big relay box itself and the other side. The side with the relay is where the hot power from the wall goes. The live power line goes into the middle one, the common pin, COM or C. The two on the sides should be labeled NO and NC for normally open and normally closed. Pick the one you want to use (depends what default state you want: on or off). Let's say you picked normally open (NO). Then wire from the NO connector to your actual appliance that you want to power. The ground wire from the wall plug should go directly to the ground connector on your device. The other pin will remain unconnected (NC in this case).
NOTE: If you are cutting an extension cord, the only wire you need to snip is the live power wire. The ground/neutral can stay connected all the way, uninterrupted. All we are doing is inserting the switch in the hot power line. (Green = Ground; White = Neutral; Black = LIVE HOT WIRE)
On the other side, opposite from the relay box, there are three connectors. Those all connect to the microcontroller: 5V, GROUND, and the input signal to toggle the relay. DC+/VCC is the 5V (or potentially 3.3V on some models too). DC-/GND is the GROUND. IN is the input signal (high or low, depending.)
You can switch the jumper on the board to switch whether it's toggled by low or high signal.
See the dedicated page, Synology DS418.