Tired of carrying around old-fashioned metal keys to your home? You’re probably already carrying a smartphone. Wouldn’t it be much more convenient to open your front door via an app that you built for your smartphone instead?
In this project, we are going to use an inexpensive, first generation Android phone. We will connect it to a Sparkfun IOIO (“yo-yo”) board and a relay switch to operate an electrified door latch. The first-gen Android phone will run a server that will respond to your unlock requests sent from a second Android phone running the door unlock client. When the unlock request is triggered, the server phone will snap a photo using the phone’s built-in camera and silently email the captured image to you. Let’s go and make it!
Servo motors are great little components that are
often used in radio-controlled cars to control
steering and the control surfaces on model aircraft.
They come in a variety of sizes for different types
of applications, and their wide use in models
makes them relatively inexpensive.
Unlike normal motors, they do not rotate
continuously; rather, you set them to a particular
angle using a PWM signal. They contain their own
control electronics to do this, so all you have to
What We’re Doing:
.:A Single Servo:.
Spinning a motor is good fun but when it comes to projects
where motion control is required they tend to leave us wanting more. The answer? Hobby servos. They are mass produced,
widely available and cost anything from a couple of dollars to hundreds. Inside is a small gearbox (to make the movement more powerful) and some electronics (to make it easier to control). A standard servo is positionable from 0 to 180 degrees. Positioning is controlled through a timed pulse, between 1.25 milliseconds (0 degrees) and 1.75 milliseconds (180 degrees) (1.5milliseconds for 90 degrees). Timing varies between manufacturer . If the pulse is sent every 25-50 milliseconds the servo will run...
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