some projects i’ve done in physical computing.
This is my toy organ, It was made using half of the 556 timer ic which is just two 555 chips in one. By pressing one of the buttons on the left side of the board you produce a tone which is determined by the values of the capacitors and resistors attached to the button.
This is a multivibrator, the two transistors are wired in such a way that when one is on the other is off. They switch from on to off and back and forth. The leds indicate which transistor is on, in this photo the transistor on the right is on.
This project uses the 556 chip again. This time i have the 556 running in astable mode, it is outputting a signal that goes from high to low or on to off. The leds in the upper right of the photo are used to help show what the signal is doing, if it were running one would blink off and one would be on, then they would switch. The speed all depends on the values of capacitors and resistors used.
Here is the 556 running in monostable mode. That means there’s just one signal coming out of the chip and it stays the same. The led is used here again so that we can see what the chip is doing.
Using Light
This is the first of two simple projects/circuits that used light as some type of control. Here is a project where we were given light to voltage converters. The converter is hooked up to the battery, then to the transistor which then outputs a signal that turns on the led. The converter acts like a switch and turns the transistor on and off. This is all dependent on whether light hits the converter or not.
Here is a similar project. This one uses a ldr or light dependent resistor. The ldr is connected to a transistor which then sends a signal to the led. The brightness of the led is determined by the amount of light that hits the ldr.
here are some links with more about the 556:
http://www.kpsec.freeuk.com/555timer.htm
http://en.wikipedia.org/wiki/555_timer_IC