Current projects and news
Since I didn't post anything for almost a year, it would be good idea to introduce you with some of my previous and current projects that I am working on.
Project 1: Vehicle Inductive Loop Detector. This device is used to detect presence of vehicles above the wire-loop buried in road. It took me few months to perfect this project and current version of this device is v2.1 (third).
Project 2: Word Clock v2. Front panel is now looking much better because I used a car tinting foil to darken not-illuminated letters. You can see the effect of this foil in the photos later. Electronics are also replaced, new PCBs were designed and factory made.
Project 3: Vehicle-activated sign - a road sign that displays current vehicle's speed by using Doppler radar technology and 7-segment display. This project is currently on hold until Project 4 is done.
Project 4: This project doesn't have an official name yet, but it is used to control home appliances over the Internet.
Word Clock - published
I have been seeing these "Word Clocks" all over the internet for the past few years, but they never really impressed me much. Mostly because there is nothing special about them (from the electronics point of view) but after seeing QlockTwo made by Biegert&Funk I simply couldn't resist making one that looks that nice.
But of course, in my local language. Aside from different language, I wanted it to be able to display full time - every minute of an hour - so I ended up using 248 white LEDs. To keep that stealthy look I used two capacitive touch sensors under the glass (near left and right LED dots) as buttons for the user-input.
Electronic gear shifter for bicycle
To change gears on your bicycle via button would be an awesome feature, something like manumatic (triptronic) transmission in cars.
Nabil successfully hacked his bicycle and added a servo motor to rear derailleur which now allows him to shift gears via two buttons. Servo is controlled with Arduino board and two buttons that change gears are located in one of the bike handlebars.
Hack involved removing a spring from rear derailleur mechanism to make shifting easier for the small servo motor.
Speed measurement using webcam
If you ever wanted to know the speed of moving vehicles in your neighborhood, well, now there is a cheap and simple solution to find that out. It turns out that it is enough to point your webcam to the street and start the appropriate software!
In order to measure the speed we need two parameters: time and distance traveled. Here we have a solution that uses web camera and Python script to figure out both of those parameters by finding difference in pixels of consequent images and calculate the speed of moving object that is detected as moving.
Be sure to read the entire article on the next page and to take look at the Python script that does the job!
Source: John - More Fun Science
Sip and Puff iPod Dock Controller
By definition, Sip and Puff technology is a method used to send signals to devices using air pressure by sipping (inhaling) or puffing (exhaling) on a tube.
Detecting positive and negative air pressures in that tube can be done by using an air pressure sensor, the resulting pressure can be read from a sensor with ADC input pin of a microcontroller where in turn the microcontroller can control some device. In this case, that device is an iPod and the project name is Sip-n-Puff Arduino Shield.
Be sure to check the video where the author explains this method using Arduino in details.
Source: Bob Johnson
Improving DCF77 reception over longer distances
While working on their open source hardware Nixie Tube Clock, guys over at the Electronics-Lab.com are also working on DCF77 time synchronization part.
The DCF77 transmitter is located in Germany (Frankfurt) and they are trying to receive the signal from a distance of more than 1500 km away. They did some interesting testing with different antenna sizes and posted their results online: "It seems that antenna selection affects received signal quality, bigger length and better tunning plays significant role in reception in long distances form DCF transmitter. So if you plan to use a DCF receiver on long distances, look for a better antenna."
Source: Electronics-Lab.com Blog
3-axis accelerometer with MMA7361L and PIC
If you are looking for a 3-axis accelerometer IC for your next project, take look at the Freescale MMA7361L. It is very simple to use by connecting it to ADC input of your favorite microcontroller and reading analog values which represent value of currently applied G-force.
Here is a very nice looking evaluation board that is built around PIC16F887 microcontroller. It connects to USB for power and has an LED display for all three axes.
Be sure to check out the video of this board in action.
Source: Viktors DIY
If you have a habit of misplacing your keys you might want to consider building this Bluetooth enabled key finding keychain.
It is based on low power consumption MSP430 microcontroller from Texas Instruments and a Bluetooth module. It has a rechargeable Li-Ion battery inside with a dedicated charging IC. The BT module is made to be always discoverable and after connecting to it the keychain starts to beep. Then you can look for your keys by listening to the buzzer. There is also a mobile application for the phone that should be used to connect to the keychain.
Now all you need to do is make sure you don't lose your phone.
Source: Kernel Hacks