personal-site/content/plant-waterer.md

Title: Automatic Plant Waterer
Date: 2014-06-05
Category: Projects
Summary: A device that automatically waters plants.

One day I decided watering my one plant was too much work, so I automated it.
It's also great for when I'm on vacation. The plant is a year old now and
doesn't look as good as it used to (kinda like you). So this machine is like its
life support.

<span class="aside">Update: this plant died long ago</span>

![the device and pump on a 2L pop bottle with a tube running to a flowerpot]({static}/images/plant-waterer/waterer1.jpg)

## First Attempt

The design was very simple and soldered together on perf board. A
microcontroller turns the pump on for 20 seconds, then waits 24 hours and
restarts. The pump ran way too fast so it was slowed down to 10% power.

This design suffered from a fatal problem. After running, there was a chance
that the tube would stay full of fluid. If the water level in the pop bottle was
too high, it could siphon out. I woke up with a flower pot overflowing with
water a couple of times.

![a new version feeding into a different plant]({static}/images/plant-waterer/waterer2.jpg)

## Second Attempt

I liked the idea so much that I made a second iteration. This one used a custom
printed circuit board with a lot more features. The pumping duration could be
adjusted with a screwdriver. This was useful as the plant (now a
[Ming aralia](https://en.wikipedia.org/wiki/Polyscias_fruticosa)) grew.

Another feature was the ability to run the pump backwards. This completely
eliminated the siphoning problem from before. After pumping for a set duration,
it would run backwards until the tube was cleared of water.

<span class="aside">Also dead :(</span>

![the new version beside a big Ming aralia plant with bushy drooping leaves and skinny stems]({static}/images/plant-waterer/waterer3.jpg)