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Digital Electronics Interactive Tutors

These Digital Tutors are interactive and started with very basic JavaScript and CSS. You can operate the controls and see the Truth Table and Results in LED Displays. Controls include DIP Switches and Push Buttons.

Tutorials on Digital Electronics

Digital Electronics Interactive Tutors

In Electronics Theory Section

Here is a Snapshot of a Live iGoogle Page showing a Digital Preset counter Gadget in Canvas view.
Other Gadgets are Logic Gates Tutor and Digital Timer

Embedded Linux Devices and Gadgets

When you look at the History of Operating Systems, you will see that that an OS that meant serious business was UNIX. It was the anvil for the creation of the C Language and AWK. Now we have Linux, the evolved Unix like OS, which is comfortable and versatile for Networking and Clustering.

Embedded Linux is not only Open Source, but can be adapted to any type of dedicated embedded system. It is more like a configurable firmware for Embedded Equipment. Its ability to manage multiple tasks efficiently makes it more friendly and stable, compared to any other OS.

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Here is a Embedded Linux Wiki for the embedded product design community.

Gadgets and Appliances are become increasingly complex. More memory and CPU power for small devices are commonplace. Linux is one OS that can be muntzed to the smallest size. This helps developers make something like a super-firmware. Just what you need for that device, can be the OS.

Touchscreens for Home Appliances, wireless networking and web enabled consumer electronics make Linux an excellent escalation from “Firmware”. For tiny systems a firmware is the OS. For complex devices today, Linux is user configured firmware.

Leopardboard DM355

Leopardboard DM355

  • High-performance Digital Media System on Chip
  • ARM926EJ-S core
  • Video Processing Subsystem (VPSS)

DM355 combines high performance MPEG4 HD (720p) codecs and JPEG codecs up to 50M pixels per second, high quality, and low power consumption at a very low price point.

Seamless interface to most additional external devices required for a complete digital camera implementation.

Self Tuning or Trainable Fuzzy Controllers

A closed loop controller is the heart of an Industrial Automation System. Right from an On-Off Hysteresis Controller to a Auto Tune PID Controller, we find solutions of different complexities. Each solution might suit a particular system; depending on the requirements of Ease-of-use, Cost and Process Type.

The Evolution of Temperature Control

  • Bimetal Thermostat
  • Analog Dial On-Off Controller.
  • Analog Dial Proportional Controller.
  • Digital Display – Analog Controller – On-Off.
  • Digital Display – Analog Controller – Proportional.
  • Digital Display – Analog Controller – PID.
  • Microcontroller Based Process Controller. (On-Off, Prop., Universal TC, RTD, mA Input)
  • Process Profile Controller (Microcontroller Based).
  • Microcontroller Based Fuzzy or Auto-Tune PID Controller.
  • Data Logger, Computer, PLC or SCADA based Solutions.

Even today, the controllers at every stage of evolution, from the thermostat to Auto-Tune, are used in many countries, for many different industrial applications. No solution above is obsolete! The developing Countries still use electro-mechanical or semi-automatic means for control in some areas.

A PC based multiplexed scanner controller with data-acquisition cards and I/O Cards can be solution for Laboratory or Research. This is used when real time control is not required or where the control failure will not lead to damage or loss.

A PLC or Microcontroller based controller should be used with a Analog Controller Protection or Over temperature Trip-Alarm.

Outputs could be Relay or SSR, Voltage and Current outputs like 0-10V and 4-20mA are needed sometimes to drive DC/AC Drives or to control Motorized Valves. Relays and SSR can be On-Off or Time proportional (PWM). The Cycle times can be 10-20 Secs for Electromagnetic Relay and around 1 Sec for SSR. This is because Mechanical Relays and contacters have limited number of operations. The zero crossing SSR has to be cycled slower than mains frequency.

In Curing rubber, which is one of the more complicated process, we need a profile based controller, which also triggers other timers or counters which need to be activated at different segments.

When a very big area is controlled, with materials or load placed un-symmetrically, Every corner or section has to have separate sensor and controller. These are then governed by a SCADA, Supervisory PLC or Master Controller.

Even a Big Die for Plastic Moulding with an Unsymmetrical Object or long object to be moulded; needs compensation for sides which will absorb more heat.

Virtual Robotics Lab – building a mobile robot

Robotics is the Magnum Opus of Engineering, It combines Electronics, Mechanical, Computing and also the toughest science know to mankind…. Wireless Networking!

Ethernet Networking itself is complex, A self healing, hack proof and plug-play Wireless Router has to be the first step to make safe robots.

From Virtual Anthropomorphic Robots to Androids

Just imagine a Wireless Router or even a Internet Router as easy to tune as a FM radio, no entering numbers, no admin with browser. Just keep it in a room and all gadgets and computers form a fuzzy network, all by themselves. The very idea of technology is to make things simple, cost-effective and efficient.

The real need of robots now is to avoid Humans in Hazardous Environment. Right from Outer Space to working in a Plant with Toxic Chemical Gases, Even machinery and equipment that injures the limbs or damages the eyes.

Virtualization in Robotics –

If workers can wear a coat of sensors with force feedback actuators, they can control a semi-automatic robot in Real-Time. This enables a worker to navigate a robot into a hazardous environment, perform an upgrade or make repairs. An accident or mishap will damage the robot and it can be easily rebuilt or maintained.

The robot is automatic and will have reflexes defined by software. The wireless networking will connect the Robot mechanically to a human in a safe enclosure. This makes the Worker present virtually inside the Robot, because he is connected by optical, aural and mechanical-muscle feedback-sensors. This will create Virtual Anthropomorphic Robots for Industrial use and may help to finally develop Fuzzy Robots or Androids, which is still in the relm of science fiction.

Related Reading –

Power Designer and WEBENCH

The WEBENCH environment provides the end-to-end design and prototyping tools you need to create power supplies or DC-DC Converters that meet your design requirements.

WEBENCH Power Designer and Architect

Power Designer – Expert Tips and Techniques for Power Supply Design. Examples – Simple Switcher, Power Supply, Voltage References, Lighting, Battery Management, Voltage Regulators, DC-DC Voltage Converters.

Power Designer and WEBENCH

WEBENCH Power Architect lets engineers quickly design and simulate a complete power supply system for any number of supplies and outputs. System designers can optimize the entire power supply system for small footprint, high efficiency, and cost in minutes.

  • Quickly design and simulate your entire power supply system
  • Easily configure the power supply load requirements for voltage and current
  • Optimize the overall footprint, efficiency, and BOM cost for the entire system
  • Get the schematic and BOM for the complete power supply system
  • Perform electrical simulation and thermal simulation

Wide-Bandwidth-Dual-JFET-Opamp-LF353-NS

LF353 – Wide Bandwidth Dual JFET Input Operational Amplifier

These devices are low cost, high speed, dual JFET input operational amplifiers with an internally trimmed input offset voltage (BI-FET II™ technology). They require low supply current yet maintain a large gain bandwidth product and fast slew rate. In addition, well matched high voltage JFET input devices provide very low input bias and offset currents.

  • Gain Bandwidth 4 MHz
  • Slew Rate 13 Volts/usec
  • Offset Voltage 10 mV

Closed Loop Control System and Runaway Process

A Closed Loop Control System is the most important aspect of Maintenance, Regulation and Stability in any Live Process. Nature itself is self regulated in an intricate fashion, a keen observer can notice the subtle controls. In Human Created Industrial systems we have Process control as a complex science. We can start by understanding a Simple One.

When you fill a Bucket with water, You keep an eye on the Level of water, as you open the Analog Tap, which is an equivalent of a Motor operated Valve. Your Eye is an advanced Optical Sensor, which is able to sense the level by the computation in the brain, which in turn operates the muscles of your hand, thru the nervous system. The hand along with the Water Tap is is the Actuator. As the water fills up close to the top, you start reduction of the water flow and keep observing, then as it tops up, you tweak the tap to a trickle. When it reaches the limit you shut off the tap.

While you are half way filling the bucket, what happens if you take a short nap, or a friend comes by and you are get absorbed in conversation, the water overflows and goes waste. Then someone raises an alarm after the Runaway process happens. This is of minor consequence, but it is not so in the case of Temperature, Pressure and also many common systems like the driving of an Automobile. Remember the gears, brakes, accelerator to control and steer the car to the correct destination, a Runaway Process causes an accident.

In Industrial Control when a Runaway process can result in danger or wastage, it is necessary to have a multi tier protection. It is also better to limit the open loop maximum to a level which will not cause much damage. So when you need that extra heat, power or flow, use booster actuators which will operate for timed bursts in the beginning of the process. An independent watchdog controller which will shut off power supply to the entire system when a runaway possibility is sensed. This can only be manually turned on after repairing the failed part or controller. A SCADA interfaced to communication systems can further alert the security, safety and fire departments.

Anantha Narayan

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