ideas of delabs

Analog Design to Handheld Computing. Ergonomics and GUI Usability. 30+ years in Electronic Product Design. 80s EE Design Notes, 90s EE Web Logs. - delabs Technologies

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Tuesday, March 13, 2018

Instrumentation Amp - Op-Amp Designs

This is the best Instrumentation OpAmp, Great CMRR, ensure supply has no ripple and keep analog and digital grounds separate. Ri can be replaced with a trimpot and resistor to alter gain. Connect a preset ends to pins 1 and 8 and preset wiper to VCC for Offset Null when high gains are configured.

Instrumentation Amp - Op-Amp Designs

Instrumentation Amp - Op-Amp Designs

The Input zeners and diodes form a protective clamp for all voltages above VCC-VDD. If supply is changed to +12 -12 change zeners to 12V zeners. Use similar Zeners at output to protect Output from being zapped by over-voltages or high energy - voltage or frequency transients. Add plastic capacitors across Rf for damping AC operation or ripple. Also avoid floating inputs by providing a bias, till you connect it to a sensor; or you will see electrometer like effects.


Monday, March 05, 2018

Analog Interface for PC Ports

Here are examples of an analog Input and Output interface for Printer Port. There are two visual basic demo programs with source to test out idea.

Analog Interface for PC Ports

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.

Analog Interface for PC Ports

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.

See the Hardware Book connector details, cables, adapters, etc. The RS232-Serial Port, The Parallel- Centronics port, The USB-firefire port are 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.

The circuits and code have some errors, The documentation is not complete.
DVM = digital volt meter MVS = milli volt source