Building an Arduino-powered, mobile-controlled irrigation system | Hacker News Reader

Building an Arduino-powered, mobile-controlled irrigation system

stavros.io

62 pointsStavrosK20 comments

It seems to me that the following is liable to misclassify some pressure drop events as normal shutoffs: > } else if ((statesChanged[2] == 1 && pinStates[2] == OFF) && > (statesChanged[3] == 1 && pinStates[3] == OFF)) {

We look at the relay outputs twice a second and expect to see two of them switch within the same half-second in some cases. Even if they were actually depowered at the same instant in time, you'd often get a tens of millis window when one of them is already off, but the other isn't; then (irrespective of which was off first) you'd get a "Pump stopped" notification instead of a "Pressure dropped" notification. Am I missing something obvious or is that case just rare enough that handling it isn't worth the complexity?

I really like how this kind of technology is finally very cheap and even usable for non-experts.

However, why is it that this kind of electronics is only ever used to irrigate plants, open/close doors or windows and maybe control lights in a room.

The arduino platform seems very popular, yet where are the really amazing projects? It really seems like it's just some kind of Lego for grownups. I bought some of this stuff too and it is cool to play with electronics, but it seems to me this stuff is merely good for learning electronics and just a fun hobby.

I've done some fun stuff with Arduinos, but sadly when I try to post it here it never makes it to the front page. For example check out this smart cocktail shaker project that uses Arduino & Android with a kitchen scale: http://learn.adafruit.com/smart-cocktail-shaker

Cool project, this combined with a database where you told it what ingredients you had available and it told you all the drink recipes that are you can possibly make would be killer for learning new drinks at home. Furthermore, also suggesting ingredients you should add to your bar next to maximize the number of new recipes available to you would be amazing. Add the ability to keep track of what you tried and your ability to add star ratings per drink would be an amazing product. I can think of few better ways to explore the world of cocktails and keep track of what you really enjoy in a drink.

In general, thinking about amazing embedded projects of reasonable scope is quite hard.It's like inventing a new product. You can see phenomena this also is final year undergraduate projects in electronic engineering - very few are "amazing".

But still, some nice ones:

http://www.instructables.com/id/20-Unbelievable-Arduino-Proj...

http://arstechnica.com/information-technology/2013/05/11-ard...

What sort of project do you have in mind, for example?

There's a pretty sizeable community that uses them to fly model aircraft: http://ardupilot.com/

There was a post today about making your own keyboard on HN today; I think that qualifies? But otherwise I tend to agree with you, from what I've seen so far.

Indian farmers were doing something similar back in 2009: http://www.pcworld.com/article/168895/article.html

How secure is it to connect an Arduino to the internet? Does it support any secure protocols?

Not directly--with only 32kb of program space in the Arduino Uno you can just barely get a wifi stack in (see the CC3000 chip), but there's no room left for SSL or anything secure.

A better option is something like the Arduino Yun which has two processors, a small Atmel microcontroller and an Atheros system on a chip running OpenWRT linux. The linux processor can act as a bridge to let the microcontroller communicate with the internet pretty easily.

At that point, just use a RaspberryPi unless you're specifically doing it for the challenge of it. Arduino is fun though.

Not really. There are some pretty considerable disadvantages to using the Raspberry Pi for the sorts of things the Arduino excels at. There are more, more resilient GPIO ports, there are more ADC ports, there are more PWM ports, the Yun can enumerate itself as a USB slave device, which can allow for all sorts of other cool uses, etc. Each device has pros and cons that you have to take into consideration.

What are some uses of a USB slave device?

It can be, to your computer, like any other USB device. So you can set it up to be a USB keyboard, USB joystick, USB storage device, etc. So, when you plug it in, you can have it set up that configuring the device, or getting logs, works like any other file operation, similar to how the wifly looks to a camera like just another sd card. Or have it enumerate as a usb input device, and use it to control and be controlled by a pdp 11 front panel ( http://retrocmp.com/projects/pdp-1170-panel/25-pdp-1170-cons... ). In short, it lets you tie whatever real-world interface device you've made to whatever pre-existing computing metaphor makes the most sense...or creating your own driver to let the sky be the limit.

Cool, thanks for the explanation.

There's also https://www.spark.io/

I would be leery to put an arduino directly on a public ip, best to have some home bastion server you log into then access your private network.

This advice goes for many other set ups as well.

Besides secure protocols, if these things are widely deployed in this manner, I'm imagining stack overflow attacks that seem impossible to avoid in some uses of C and C++.

You can use the Standard Firmdata sketch, and then use whatever you want. For example, Node.js with Jhonny-five: https://github.com/rwaldron/johnny-five

I use it together with a pcDuino and it works like a charm.

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