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Analog Interface for PC Ports

• ICL7135 to Printer port 4-1/2 DVM.
  
• Milli Volt Source for Printer Port.
  

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Device Data Interface :

In the early days data interface was possible by the RS232 or Serial Port and the Parallel or Printer Port. Analog gets converted to Digital Data and then sent into the PC.

The Software in the PC along with the Interfaced Hardware could create a Virtual Instrument, Test Automation or Data Acquisition System.

DVM = digital volt meter   and   MVS = milli volt source  - Here are simple educational examples of an analog Input and Output interface for Printer Port. There are two visual basic demo programs with source to test out idea.

USB and wireless interface to PC may be more in vogue, but a higher speed is possible in printer-port. For analog and digital fast data acquisition, PC cards to full Access to PC bus are the best choice.

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The Sensors and Actuators interfaced with a computer form a basic automation system or even a robot. So learning to interface Sensors (input devices like a thermocouple or pH sensor) and Actuators  (output devices like a motor or heater) with a PC is the best way to start. It is by studying examples and experimenting cautiously can one learn the science, book reading alone will never help.

The RS232-Serial Port, The Parallel - Centronics port, The USB port is good to start with. Then you can interface by LAN or Wireless- LAN or  TCP/IP-Internet to make Robots or Automation extend to multiple places and computers. The possibilities are endless, imagination is the limit for students. But entrepreneurs need to be  practical and only make equipment that have a utility and sensible market scope.

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Any Tablet with an external Hardware can make a nice Instrument. The professional part lies in that external hardware and usability of the software or app. Windows Virtual Instrumentation are well known. Things like USB Scope and Data Loggers have been there for decades.

Virtual Instruments for Tablet Computers have a nice future in Industrial, Automotive and Measurement areas. You could start by Interfacing with Bluetooth, USB and then move to IoT and WSN.