How can I switch on and off a bulb by using a computer?

Answer 1

Since there are millions of old 8088, 80186, 80286, 80386 and
80486 computers, I was looking for a CHEAP, simple, way of
using these, for programming external devices ( robots ).
I used a piece of cardboard ( instead of circuit board ) and
cheap chips ( from Radio Shack ) to make a cheap interface
to the existing Parallel port ( printer port ).
If you want to turn off just ' One " bulb, you only need one logic
chip ( say , ANY CMOS 4000 series chip ) and a few resistors,
and one general purpose transistor to turn on any RELAY.
If the bulb is an LED ( Light Emitting Diode ) you can turn on and
off 8 LEDs ( data bits ) on the 8 Data pins of the parallel port
using only the resistor and the LED. You can also turn off and
on the 4 Control bits, with another 4 LEDs.
To turn on and off just one LED, see my website,
kidbots.com
for the general instructions. The LED is connected positive
( A typical LED had a CUP and a POST inside the plastic. the
CUP is Negative, the post is POSITIVE ) to a 5 volt source,
typically the RED wire on the Red, Black, Black, Yellow harddrive
connector of the computer, and the negative post goes thru a resistor, typically 330 Ohms to the DATA pin. Very simple.
The program to turn off and on the DATA pins is listed on the
kidbots site, with a pin diagram ( it is a poor one, check online
for parallel pinout ). I use QBASIC in DOS, since old computers
typically had NO harddrive, and the entire program to control a
robot can be put on a single floppy !
Hope this helps.

robin

Answer 2

Assistive tech equipment is available to switch on & off outlets. It usually connects to a 9 pin serial output. (some laptops don't come with that now). For more money I'm sure you can get usb or maybe now even bluetooth but I haven't seen it yet.

Do a search on Assistive Tech PC Control

Answer 3

And I thought I was lazy, lol