308
Tibbo Project System (TPS)
© Tibbo Technology Inc.
Details
Transistors are rated for the maximum voltage of 24V and the maximum per-channel
current of 0.5A. Note that the maximum current should not be exceeded even at
lower voltages. Do not apply negative voltage!
To open a transistor, set the corresponding control line LOW. When left
unconnected, control lines default to HIGH (and, hence, transistors will be closed).
Combine this Tibbit with terminal block devices --
(four terminal blocks). Note that #21 doesn't provide the ground line, and using this
Tibbit requires the ground line between the outside world and your system. Hence, if
you use Tibbit #21 you will need to "steal" the ground somewhere else.
One additional possible use of this Tibbit is for the emulation of clock/data or
Wiegand card readers. Our programmable devices (such as
) have
the unique ability to output data in the clock/data or Wiegand format. This is
achieved through the ser. object running in the clock/data or Wiegand mode. Card
readers usually have open collector outputs so this Tibbit is ideally suited as the
hardware front-end for the job. For this to work, the Tibbit has to be connected to
the TX and RTS lines of the CPU's UART (see
).
As with many "real" readers, the equipment on the receiving end will need pull-up
resistors.
LEDs
There are four red LEDs which are connected to four control lines. All LEDs are
buffered (using logic gates) and light up for the LOW state of control lines (i.e.
when transistors are in the opened state).