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Astable Multivibrator with 555

This is a demo of the popular 555 timer. you can try out the project on this page by a javascript simulation.Press the Red button below to turn on the circuit press it again to turn off. The 555 can source (LED2) or Sink (LED1) upto 200mA.

Screenshot of Astable 555 Timer Flasher

It can even drive a small motor or lamp with diodes added to protect from inductive kickback.Vary Ra, Rb and Ct with the controls given and see the change of frequency, period and duty cycle.


Astable Multivibrator with 555

Astable Multivibrator with 555

This is a tutorial with calculator to help learn the application of 555 which is a very rare chip innovation. It is simple, versatile, flexible and programmable (by tweaking of pots).

Mini RTD Pt100 Three Wire Transmitter

These are the circuits and boards of a Mini Temperature Transmitter for a Platinum hundred ohms temperature Sensor.

Transmitter RTD

The customer wanted a two wire system, this needs low power opamps which were ten times the price. If this transmitter works at 3mA it could have been two wire. Those parts were in short supply and the budget of customer was low. So i made it with regular opamps but three wire. The customer was satisfied as he got a cost effective solution. But now the situation of markets and products are different.

RTD  Three Wire Transmitter

If you need to transmit the temperature from a high voltage area or toxic environment. You will need to hermetically seal the transmitters, convert the Voltage to frequency, frequency to IR LED flashes or RF. This can be then remotely monitored. Then the transmitter has to be battery-solar operated, low power too. ICL7135 is a simple solution. It has a serial output that can be used to Drive IR Leds. Remotely sense these flashes in a Micro-controller and you have a reading. You may be able to use optic-fibers too. Where volatile liquids are present so that the risks of sparks can be eliminated.

3 Wire Transmitter RTD

More at Process Control Circuits

This is the same Mini RTD Pt-100 Transmitter but in its case. Encapsulated in epoxy, hermetically sealed against harsh industrial environment. This will work well even near fumes of Ammonia with no corrosion. But not near vapors which can be ignited by sparking as terminals are still open. The side view shows zero and full scale ten turn bourns trimpots heads, for calibration. After cal it can be sealed with RTV compound.

Digital Alarm Clock Gadget

An Alarm Clock with Musical Alarms. This Web Widget was for the iGoogle Homepage, A Web-page or even a blog.  It was an Experiment in User Interface in small a small Facia or Front Panel.

You can set Five Alarms with Ten Selectable Musical Sounds and a small Text memo.- 2005

Digital Alarm Clock Gadget

The Project Page digital-alarm-clock

The simulation is as close as possible to a uC based Clock which you could build, The GUI is more like a electronic gadget than a Software Application. That should charge you to build your Alarm Clock today.

Eco Green Alarm Clock with Flash Sound

Get news Eco Version above, This page is of the Older Version of Digital Alarm Clock. The reason this is old is it sound integration is not very good.

Digital Alarm Clock Web Gadget with Musical Alarms

Usability and Ergonomics Research

This gadget has established usability problems. The were intended and demonstrated. It was an attempt to show the limits and strain associated with push button and key controls to operate an electronic equipment.

Many Apps, Appliance and Gizmos are constrained with a small control interface size, these pose a challenge for the User Interface design. I myself have problems with the keyboard phones and remote control. This can be seen even in the puzzling Monitor OSD controls in comparison to the easy analog Pot controls of old CGA/EGA Monitors.

Controls should be easy like the water tap or power switch. Not like a Puzzle, Maze or Quiz.

Technology needs to make things simple. Keep controls minimum and Human Friendly means (analog). A human Being is a “Real Time Analog Machine”. This gadget is a continuing experiment in ergonomics.

Date Time Clock Widgets

I wanted to realize usability of controls within a small footprint. This lead to some innovations.
These are JavaScript and CSS Clock Widgets originally made for my webpage later improved and decorated for iGoogle. Now available as web widgets.

Date Time Clock Widgets

Date Time Clock Widgets

When i found the Remote controls and the early mobile phones difficult to use. I felt i have to try to design user interface within a small footprint. This helped me innovate a Active or Dynamic GUI concept; as shown in the Ability to change the skins of the Audio Music player and Digital Alarm Clock. The metronome too see the other project in this profile. These were done around 2005-6-7. Both for elements on my site and gadgets.

Digital and Analog Clocks

I also made a Virtual Web Gadget Alarm Clock Simulation that will demonstrate a Dynamic GUI in a Limited Facia Area.

Conclusions –

Reduce the number of operations a user would do at achieve a purpose. Auto, Intuitive, Context Gui. When a Customer comes to buy Trousers, Take him to the Trouser Corner. Do not show Tuxedo option. The colors have good contrast and the text clearly visible.

A Highlighted reaction to user action. Tactile. Dynamic GUI, see in Gadgets above. GUI Elements appear only for that sequence of actions. No clutter. Menus if used, should not get stuck. Should not be fidgety, should not be menus at all if possible.

Engineering, Interaction Design, UI/UX