Sunday, November 8, 2009

Servo Motor Control with an Arduino

As the title suggests, the objective of this setup is to control a servo motor with an arduino. The control values will be passed to the arduino from a potentiometer. The schematic is shown below.

(image courtesy of itp. The complete tutorial and the arduino code is here.)

Here's a video.

Transistor Lab

Here I'll be using a transistor to control a dc motor. The connections are as shown below.

(image courtesy of itp. The complete tutorial is here.)

The reading from the potentiometer connected to the analog 0 pin of the arduino controls the dc motor connected to the collector of the transistor.

Here are a couple of pictures of the setup.

Saturday, September 19, 2009

Sound LED

So taking Rory's lab as a point of departure, I decided to add a few elements to spice things up a bit. In this demo, instead of using a potentiometer to control the brightness of the LED, I'll be using sound. That is, the loudness of the sound determines how bright or soft the LED will glow - the louder the sound, the brighter the LED.

I used a simple audio pre-amp that was lying around on my breadboard from a previous project to setup the input. The schematic is shown below.
The output from the pre-amp section (figure 1) goes into a line driver stage (figure 2, optional, just to steady things a bit and in case you want a 3 wire configuration instead of a 2 wire) and then into the analog in of the arduino ( instead of the potentiometer as in Rory's session). The rest of the circuit (from arduino out to LED) and the code is the same as Rory's. Here's the video.

I couldn't find a steady monotone to experiment with (my voice failed miserably and I don't own an oscillator). So in the second part of the video I'm using a sruthi box (the next best thing I could find). Notice the LED on the left of the screen.

Friday, September 11, 2009

Sensor Walk: Sandeep goes to White Castle

Interaction with sensors that I saw/heard:

Car Horn
Opening an umbrella
Automatic Wheel Chair (I live next to an old age home)
Automatic Doors (with reference to the aforementioned old age home)
Shop shutters
Street light switch
Coke Machine
The order screen at White Castle
Credit card machine

Physical Computing

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