Wednesday, July 11, 2012

Wifi garage door opener

I took apart my last garage door opener because there's another project that needs my bluetooth antenna. I realized how much easier the garage door opener would be to make over wifi and much less work to have it tidy in a permanent enclosure. Not to mention, the ethernet shield is roughly the same price as a 2nd antenna. This assumes you have wifi in your home with access from your driveway, a spare network port in your home network for the ethernet shield, and a cell phone.

In the picture is the PCB from the inside of a traditional garage door opener is laid on top of the ethernet shield + arduino uno combo. The transistor is pushed into the heated solder points of the push button with the center pin going through a 10k resistor to the output pin of your choice.
This 2nd example in this tutorial for lighting an LED can be copied without editing to use pin 2. The tutorial also walks you through testing the local address that will trigger the button. Now you can create a shortcut or bookmark to the website on your smartphone to be able to open with one click.

While this is all you need, I've also soldered wire to replace the battery. Since this one uses a 3v battery it's going to the 3.3v and ground pins on the board.

Adding to it by opening with a text

So in the rare occurance that I'd need to open the door while away (family member locked out of the house.. just takes one time). I decided to go with sending a text. For the time being I have an older android phone as a "home phone" and this script should be easy to replace the check for new texts section with anything from checking email to checking twitter and can easily grow into a smart home station. Aside from the wifi setup as the foundation, this involved downloading the SL4A app from here. Then create a Python script with the following code:

import android
import httplib
import time
droid = android.Android()
var = 1
while (var == 1):
 smscheck = droid.smsGetMessages(True, 'inbox')
 for i in smscheck.result:
  if 'Open Sesame' in i['body']:  # The command you want to send via text
   url = ''  # IP address of ethernet shield goes here
   uri = '/?2'  # Pin number being used should replace 2
   ES = httplib.HTTPConnection(url)
   ESreply = ES.getresponse()
   print ESreply

Thursday, July 5, 2012

R2-Q5 - Making a droid

I've been a Star Wars fan since my parents took me to see Return of the Jedi when I was three years old. It's one of my earliest memories. Sitting in my dad's lap in a crowded theater and seeing luke wielding a green lightsaber with the sands of Tatooine in the background.

So when I started getting the bug to make stuff last summer, I came across A sight dedicated to droid builders of the R2 variety. A great site for collaborating ideas, tutorials, or just chatting on a regular basis with people who share the interest. With any large group there are a few bad apples, but I've found this to be a great community.

Here's a photo of how my droid has been sitting since the fall.

I'm going with R2-Q5 as the designation. There's something of a 10:1 ratio for R2-D2 vs. other full size replicas and imperial droids need to represent!

This one will permanently be on all three feet. Apparently retracting feet are expensive to make, but it will be remote controlled with moving dome, opening doors, blinky lights, and sounds. The last piece I put together was a lens for the radar eye. The radar itself was made from Resin by Mansugi on 

The lens is from an arts and crafts ornament found at Michaels. An idea discussed at The diameter of the cut coincidentally matched my kitchen sink drain, which was used as a template. Yes, I went looking through the house like a Sesame Street episode looking for circles.
The ornament ball is fairly sturdy, but I put too much pressure on it trying to rush through cutting. The edge of the dome is thicker than the top, meaning the breaking point isn't going to be on the piece of scrap. This is why I'm using a knife in the picture and taking my time.

Here's the final fit before gluing in place.

Tuesday, April 3, 2012

Mad Genius Clock Design

I came up with what I believe to be a unique clock design a few months ago, but didn't have a name until today. The term mad genius was used by a friend today and I thought it fit.  The clock only has an hour hand traveling back and forth through the spindle in a 12-point star pattern.  I aim to have a physical model over the summer.  Here is a rough animation of the pattern.

Tuesday, March 20, 2012

Temperature Triggered Light Switch

The idea for this project came to me 3-4 years ago late one cold winter night when I was called by my father-in-law.  Some rural homes running on well water will have the water pump above ground and in a small building.  Many of these pump houses, like the one at the house I rented from my father-in-law, can really ruin your day or week if a pipe bursts due to below freezing conditions.  While I was appreciative of the call to save repair costs, fumbling around in a small building near mid-night looking for a lightswitch wasn't something I cared to do.

I could have hired someone, drawn an electrical line with a switch to the home, or created a wireless switch, but what if I hadn't gotten the call or what if I were out of town?  I've always wanted a smart home and this was a start to doing it cheaply.

This first photo is a prototype board with an ATmega328 flashed with Arduino.  A transformer to get power from AC is just below the picture in the box.  The relay is triggered on pin 8 when the temp sensor reads 0 degrees C or below.  The standard light switch can be used as a bypass and is mounted to the box cover.  The LM75, temp sensor shown in the second photo, was scavenges from a 2004 iMac being sent to the recycler at work.  The sensor is on a nice breakout board with connector.  I've soldered these wires to an RJ11 socket at both the base unit and for the sensor.  This will allow the sensor to be connected by a standard telephone wire.  Between power and the I2C protocol all four wires of the telephone line are being used and cheaper wire with only two wires can't be used.  To help keep the sensor weather resistent I used a clear christmas tree ornament from Michaels and sealed it with super glue.  It survived 30 seconds under a running faucette so I'm gong to attempt to hang it under the roof's over hang.

The total cost of the project was under $15 with most of the compnents repurposed from tossed electronics.  I hope to follow up with a photo of the box and switch installed in the pump house; conveniently after we've moved out of the rental house and just after another winter season.  Of course, it's always the first frost that's hardest to remember!