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Comment by wrs | Hacker News Reader

No worries. PIs do have GPIO pins, and lots of peripherals to plug into them. Nearly Adafruit’s whole product line is about hooking up random peripherals to I/O pins.

And speaking of custom household devices, I’m about to spend $30 or so at Adafruit to build a thing that texts my wife when her outdoor herb pots need watering. :)

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That sounds fun! I've been rebuilding my wife's gardens and adding drip lines / irrigation. I ended up getting an OpenSprinkerPi[1] board to control the irrigation valves I'm installing. There's also a software project[2] that gives it a little more configurability/utility, including tying it into automatic watering based on the weather and such. I'm just having a lot of fun with it, and it seems like you are too!

[1]https://rayshobby.net/wordpress/ospi/ [2]https://github.com/rszimm/sprinklers_pi

Pay more for the humidity sensor. Not the resistive ones, they fail after a short time.

I'll go a step further. Don't pay for any sensor, you can make your own resistive sensor from a couple of resistors. The reason they fail is oxidation on one terminal. If you alternate the polarity as you read the sensor, it avoids that problem.

Adafruit has a cheap capacitive sensor (using a micro controller with built in touch sensor circuitry) — but not that cheap. The polarity flip is a clever idea. Well, part of the fun is wildly over-engineering the thing, right?

Do you have any guide to this you’ve seen or can recommend?

Nope. I just did it once. I'll look around and see if I drew up a schematic.

Yes, but lifetime is still not the best.

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