The variety and low cost of these little boards is amazing.
I bought a good amount of arduino related things but have used very little. There are so many boards that do the things that I want pre built and so much cheaper than putting the required Arduino bits and pieces together.
I built a simple timer for watering my aeroponics system. For arduino required power supply, arduino and a relay. To change timing I have to plug it into a laptop. Worked fine but then there was putting it in a case, wiring it all up etc.
Contrast that to a prebuilt board where it is all onboard and to change timing I just press some buttons to change the built in display.
Power in, power out and for .60C extra I got a purpose built case. I got sick of small pums blocking and burning out so I got a 900W dirty water pump, smallest and cheapest I could find. Unfortunatel the thing literally blew the plants out of the drum they were in.
Add one little PWM motor speed controller for perfect control of water amount and all is great.
Where I can see an arduino would be better would be to add in temp control.... more frequent watering in hot weather and less when it's cooler so the plants are closer to being neither under or over watered.
Next step, ultrasonic detection so if a bird gets neat the tomatoes or corn a horn or electric scare crow is activated.
)
Not saying more could not be done with the arduino but for several simple applications I have, can't beat these little boards.
I have hooked some different ones together as well. Recent one was Christmas light Controller. Mrs wanted something to turn them on and off. Could have used a plug in time but cheaper to buy a Light sensitive switch and couple that to a timer. When it gets dark the switch turns on the lights which sets the timer going for 4.5 hours. Around Midnight the lights switch off.
Yes I wired it up and put it in an electrical conduit box as a case but that was for fun mainly. Have other uses for this thing as well....
Another one is a fan controller for my solar inverters.
Don't like how hot they get so got a thermostat board that turns a fan on when they get to 40oC.
Love these little controllers, only thing is figuring out what the heck some of them do from their Chinglish descriptions.