USB-IO adapters allows you to use the adapter pins as general purpose input/output lines.

The most functional model is DLN-4S adapter. It is available both with a plastic enclosure (DLN-4SE) and as an assembled PCB board. The main advantage of DLN-4S USB-IO adapter that you can use up to 48 IO pins, which support pull-up resistors, debounce filter and open drain mode.

You can start with DLN-4S USB-IO adapter. Later, when you clarify the requirements, you can switch to a cheaper adapter.

The DLN-4S USB-IO Adapter supports:

• 48 GPIO pins that can be used as digital inputs or digital outputs. You may set output values for digital outputs and get current values both for inputs and outputs.
• pull-up resistors at all I/O pins.
• debounce filter, which avoids sending numerous events due to contact bounce. The new value is only accepted if it is stable for a predefined period of time.
• open drain mode at all I/O pins.
• user configurable event generation conditions. When the input level meets the specified requirements in USB-IO interface, the adapter sends an event to your application.