Temperature and humidity measurements are a nice addition to many hobby projects. But [Rajendra Bhatt] makes the point that many of these sensors have a price tag that is well above what most hobbiests are willing to spend. He decided to take an in-depth look at the DHT11 sensor; which you can get your hands on for under $3 if you know where to look.
The four-pin device uses a 1-wire protocol. [Rajendra] discusses the ins and outs of the communications, demonstrating the part using a PIC 16F628. It’s a snap to connect to your project, requiring VCC, GND, and a pull-up resistor on the single data line. We’ve already seen it used on at least one project, and hope to see more of this little guy in your own hacks.
Now we found this part listed on eBay for less than $3 (buy it now price including shipping… how can they do that?). But Octopart didn’t come up with any options. If you know how to get this through traditional parts suppliers let us know in the comments.
[Stephen Albers] offers his avian friends a lot of extras with this electronically monitored bird house. This will not only give you a look at what’s going on inside, but provide a source for several other bits of data as well.
First off, a camera has been mounted to the underside of the roof. This looks down on the nesting area and features night vision so that you can peek in any time day or night. He used a WiFi webcam that operates separately from the other electronics.
With the remainder of the setup he is able to harvest temperature and humidity data inside, temperature outside, force on the bottom of the house (although this turned out to be less useful than anticipated), and a in-and-out count for the doorway provided by an IR transmitter/receiver pair.
This offers quite a bit more than the last bird house project we saw. That one also left a lot to be desired as far as protecting the electronics. [Stephen] didn’t skip on that kind of protection. Most of the electronics are housed in an acrylic chamber in the base of the house. The sensors find themselves nestled in plastic enclosures, although some work needs to be done to ensure that the temperature and humidity sensors will still function correctly with this setup.
It seems everybody has a different interpretation of the perfect alarm clock. [Loic Royer’s] alarm clock is not the loudest, or the smartest, but does have some interesting features. By monitoring several environmental factors like temperature, air quality, humidity, dew point, and your own sleep patterns, this alarm clock can determine the best moment in the morning to wake you up.
The main sensor is a wireless accelerometer with the theory being: the more you move in your sleep, the closer you are to a conscious state. The other sensors assist in picking the perfect moment, and awaken you with the sound of birds chirping.
For now all we have is the source code and the list of hardware, but for anyone wanting to try, a circuit diagram wouldn’t be too hard to figure out on your own. Check after the rift for some more videos. Continue reading “Lolo’s (perfect moment) alarm clock”
[Terry] is planning to launch his high altitude balloon within the next few days. As we’ve seen before he has gone for a general setup – GPS tracking, environment sensors including temperature and humidity and pressure, and 2 on board cameras – all with an expected height of about 100,000 feet. What makes this project unique is the transmission of live telemetry data to a Google Maps or Google Earth interface.
The planned launch date is Sunday the 24th about 00:00 UTC so long as the Civil Aviation Safety Approval for the launch is passed.
As a final note [Terry] wanted to let inspiring balloon launchers to check out the UK High Altitude Society – who have been an invaluable source of information.
As cigar aficionados will tell you, cigars should be stored in climate controlled humidors to keep them in best condition for smoking. Most of the time a humidor is just a simple air-tight box with a hygrometer attached, which measures the relative humidity inside the box. Feeling as though he needed more control over the environment he kept his cigars in, [Justin] created the Tweetidor, a humidor that tweets its current temperature and humidity. Yes, you guessed it; the project is built around an Arduino. It’s a simple, useful project that is well documented and would be fun to recreate if you’re into cigars (and not tired of Twitter or Arduinos yet.) Combine this with the laser lighter and you’ve got a pretty nice setup.