Here is a web interface for switching on your light

Like I mentioned in a previous post, I wanted to try out a more hackable wifi plug. I got a Kankun “smart” plug. Like the other one I have the software is horrible. The good news is that they left SSH enabled on it.

Once I get SSH access I got to work on a web app for it. I spent an hour styling a pretty button, look:

Screen shot of button in off state

And when you turn it on it looks like this:

Screen shot of button in on state

Anyway, if you want to have a pretty webby button for controlling you wifi socket you can grab it here.

Here is a web interface for switching on your light

Autonomous Plant Watering

Here in our house we keep our plants on the threshold of death. They are in constant limbo as we remember to water them every few months. It is really quite disgraceful.

A pathetic house plant
Our sad sad plant.

One day I looked at our plants and thought we needed to do something. Go and water them? The plant doesn’t just need water. It is suffering from the systemic problem of us never remembering to water it. No. Watering the plant would be too easy, we need a technological solution that will hydrate the plant and not require us to change our comfortable habit of neglect.

I googled “automated house plant watering” and the first link that comes up is an instructable. It promised to be a cheap and easy project. So I went ahead and got all the materials: an aquarium air pump, some tubing and valves. I then followed the instructions and assembled the parts as they describe. The result was underwhelming. I got some gurgling at the plant end of the tube, not a steady or measurable flow. I really don’t understand the physics that makes that system work, but it has a lot to do with water pressure: the deeper your reservoir the more efficient the water gets pumped. As the water gets consumed, the pump gives less output. So to get an optimal plant-watering we would need to make sure the tank is always full. Whats the point of automating it if you have to fill the tank after every watering?? This won’t do. I plan to put this on a timer. I need to know that if I have it on for 1 minute I will always pump a comparable amount of water to the plant.

So I got to thinking, how can an air pump pump water? Specifically, how can it pump water with a constant pressure? I came up with this schematic:

Brilliant schematic
Air is pumped into a sealed jar with an outlet tube that relieves the jar’s pressure by pushing water out through another tube!

I grabbed a mason jar and drilled two 3/16″ holes in the lid. This allowed me to insert the two air tube which are slightly thicker (5mm). They fit snuggly and formed a seal.

Jar lid with two tubes running through

Next I attached one of the tubes to the pump, and placed the second one’s end in a glass. Turned on the pump and! Yes! It works! Science! I was getting a steady flow of water. The jar was emptied in a constant rate. This setup will do. I’m so pleased with this!

I splurged and got a slightly more expensive pump with 4 outputs so I can water 4  plants individually.

Aquarium air pump with 4 outlets

This setup has a few advantages over other pump setups:

  • It is cheap. So far the bill of parts is around $12.50.
  • It offers predictable water throughput.
  • You can connect any sealable container. Don’t want to refill the water after 32oz of watering? Get a gallon jug.
  • If the reservoir runs dry the motor won’t catch fire. That apparently is a thing water pumps.
  • Since the water is only going through a simple tube and not an expensive motor, you can pump a nutrient solution. If you want to pamper your plants, we don’t.

I made a stupid pump. Why is that cool? Because with a WiFi plug it becomes smart! It is now a Connected Device™. I plugged it into a Bayit WiFi socket, and set it to turn on for 20 seconds each Monday afternoon. That will feed our plants about a 1/2 a cup a week. If we like the results we may extend it to a full cup!

Bayit WiFi Socket
The Internet is in control!

A Word on WiFi Sockets

They suck. They take the simplest operation of closing a circuit and abstract it in a shitty smartphone app that only works half the time. Well, at least that has been my impression with this Bayit gadget. For my next project I am going to use a Kankun smart plug. Apparently it runs OpenWRT and is very hackable.

Bill of Materials

Air Pump $6.99
Air tube $3.42
Mason jar $2.09
Wifi plug $24.99
Autonomous Plant Watering

It’s MLK Day and It’s Not Too Late to Do Something About It

For the last three years I have had the opportunity to send out a reminder to Mozilla staff that Martin Luther King Jr. Day is coming up, and that U.S. employees get the day off. It has turned into my MLK Day eve ritual. I read his letters, listen to speeches, and then I compose a belabored paragraph about Dr. King with some choice quotes.

If you didn’t get a chance to celebrate Dr. King’s legacy and the movements he was a part of, you still have a chance:

It’s MLK Day and It’s Not Too Late to Do Something About It

Look what I did to fix Mozilla

You’re welcome.
A heart shaped box with Mozilla embossed on top.

When you have a hammer, every problem looks like a nail. In my case, I have a 3D printer, and every problem is an opportunity to stare at the hypnotic movements of the extruder.

It has a nifty hinge/magnet mechanism, here is a video:

You could download and print this via the thingiverse page, or you could check out the github repo and hack on it.

Some lucky duck has me as a Secret Dino, and will be getting this in the mail soon!

Look what I did to fix Mozilla

Make pita like a pro

Anyone who comes from a pita-rich country to North America knows that you really can’t get your hands on good pita here. I came across a recipe in Hebrew that is really good, and makes fantastic doughy pitas with nice pockets.

You need:

  • 1 kg of white all-purpose flour
  • 700 g warm water
  • 2 tbsp salt
  • 2 tbsp brown sugar
  • 1 tbsp + 1 tsp yeast
  • 3 tbsp olive oil
  • pizza stone

In a large bowl, sift in the flour and mix all the dry ingredients (salt, sugar, yeast) until it is all evenly distributed. Add the olive oil, and half the the warm water. Start mixing with a spoon, and add the rest of the water slowly.

Now it’s time to get dirty (if you haven’t gotten flower on everything already). With a wet hand, reach into the bowl, and knead the dough in a twisting fashion, as if you were screwing a light bulb. If the business gets sticky, re-wet your hand as many times as needed. Does your arm hurt yet? Good. Keep twist-kneading, and switch directions every once in a while. Do this for 10 minutes.

Set the bowl aside, and let the dough rise for an hour and a half until it doubles in size.

Put pizza stone in oven and preheat it to its max temperature, my oven goes to 550 degrees F. The dough, once risen should be very airy and wet. This is good! Spill it out to a floured work surface and get control over it with flour. Now use a knife to split the dough into 16 balls. Flatten each ball with a rolling pin to create flat circles.

Baking time! Each pita will need about 2 or 3 minutes, not more. If you are seeing any browning you are a few seconds late. You should see the pita puff up and get a pocket. I managed to bake two at a time, and have a huge basket filled with fresh pita in about 15 minutes.

Make pita like a pro