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Digital Inputs
To simplify connecting sensors and switches, the sensor inputs are pulled
high to 5 volts internally so that they change states when they are connected
to ground. So no power is required to use a Snap Switch or Photo Cell,
just connect one side of the switch to the sensor input and the other
side to ground. Your PC will now be able to detect if a switch is open
or closed or if a photocell is light or dark.
Analog Input
How does it work?
The GadgetMaster converts the
voltage level at the Analog Input terminal into a rectangular pulse on
pin 15 whose width you can "read" in software. By measuring
the width (duration) of the pulse you can determine the voltage value
present on terminal 2. We think you may find this useful in lots of ways.
By connecting a fixed resistor
between the analog input and ground and a variable resistor between the
analog input and 5 volts a 'voltage divider' is created. This means that
if the variable resistance is small then the input will be close to 5
volts, if the variable resistance is large then the input will be closer
to ground
An example is the measurement
of temperature. A varistor is a resistor that has a resistance that varies
with temperature. By connecting a suitable varistor between terminal 1
and 2 and a matching resistor between terminal 2 and 3 you can measure
the temperature the varistor is sending.
Another example is the measurement
of brightness using a photocell. As the light hitting the photocell is
increased the resistance of the photocell decreases and the input voltage
will increase closer to 5 volts.
You can also measure the position
of a potentiometer shaft by connecting the potentiometer across terminals
1 and 3 with the "wiper" connected to pin 2.
We know that you will find
this new feature usefull in a lot of ways. You can always download the
User's Guide from our download area to learn more about the Analog Input.
Everything is included
12 Volt DC wall plug adapter and the parallel cable are included with
the GadgetMaster II.
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