There are many devices which can be interfaced with the PC and the PC can be used for controlling several types of hardware devices. There  are many manufacturers of hardware devices which want to add data  operations. USB has emerged as good option and it can be used for  exchanging electronic signals among several devices. The usb i2c spi adapter has I2C clock frequency up to 400kBit per second. You can interface  all types of spi devices. You can get pre-written sample code which  would work on many Operating systems. You can develop your own  controlling code with the help of API. The usb io adapter has 24  configurable digital IO pins which can be swapped and matched with  existing hardware. The adapter is RHS Compliant and can be controlled  using the API. Another spi bus adapter can be used with SPI and IO facilities on your computer. It is good see  these adapters available because for engineering devices it is easy to  control them with USB options. Diolan is prime manufacturer of the  devices which are used for aiding the automation of electrical and non  electrical devices. There are many adapters and converters available  which can be bought in bulk from this provider. Take a look at the  complete solutions from Diolan.