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Tag Archives: delabs-Portfolio

Astable Multivibrator with 555

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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.

Screenshot

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

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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

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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

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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

Usability of Front Panel Controls

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I once worked in Tek for a very short period. I got to experience the 2235 and 2465 analog scopes and their controls. The 2465 was a 400 MHz Digitally Controlled Analog Scope.

I also used the Plugin Scopes and Calibration systems that were Tek Culture and Tech contribution to the Instrumentation world, it probably evolved into VXI-PXI as uC systems took over.

I also had a chance to look at DSO/Logic Analyzers and the just developed TDS Series. The older tek analog scopes made me understand about usability and panel layouts. Many controls are inevitable in a Analog Scope with Electromechanical Interface.

Usability or Ergonomics Review

In a Digital World that can be largely changed using the Monitor and Trackballs. The older BlackBerry phones are also good study for usability before Touch Screens came.

delabs Experiments

delabs Web Widget and Application Interface Usability Experiments 2003-2008

In 2003 i tried some experiments in Web Interface. I also converted some mini DHTML Widgets i made in 2000. These i later added to iGoogle too. In 2000 it was a Midi Player later an Alarm Clock when iGoogle came. Then a Metronome and Mini-Notes Holder and a Text-Database driven Music Player.

delabs Web Widget and Application Interface Usability Experiments 2003-2008

Talking of Touch Screen, i had seen a Monitor in a Universal Pick-Place Assembly Machine. A Huge Pneumatic System, Not a SMT, there was no SMT then. This monitor had IR LED and Opto Transistor Array over the monitor. That sensed the finger Probably.

Capacitive Touch Screens and Accelerometers have given a new dimension to Ergonomics.

Then came Euro controls for Consumer Electronics. Like remote controls. Look at the National Panasonic VCR Remote on the right. It could be in the 90’s. It is so easy to operate the VCR, you do not need a manual. Flap a Lid and you have many things to do, including control any brand of TV in tandem with the VCR.

Software or hardware it is the same thing. The way the Common man sees a Gadget, like a Lamp Switch or a Water Tap.

The HTML5 thing also is in the same direction, which empowers Web Designers to make Usable Apps and Sites not just Flashy Mazes where one can get lost for eternity. Some of the sites i built are like that, Labyrinth of Docs which only the Search can Reveal.

2003 – 2008 delabs Notes

Test & Measurement Instruments by delabs

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These are Instruments that Jack built. Here read Jack as me, delabs. Some were hand made, some in the form of workflow of a small firm with professional equipment. Some made in quantities, other a couple or more for R&D.

Test & Measurement Instruments delabs

Test Measurement Instruments by delabs

Test and Measurement is all about Measurement or Metrics. Without this, every other part of electronics becomes like boneless entities.

Instruments i designed and built. (long ago).

DC Regulated Power Supply

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This is a Regulated 0-30 V DC Power Supply manufactured by me in small numbers, 0-30V 5A and 5V -5A. It had a Switching Preregulator. This keeps the Vce across Transistor Bank at the Back of Instrument, at the lowest possible level, in order to keep them Cool. When Vce and Ic both are more in a Power transistor it will get heated more, then the efficiency of power supply is low.

Variable Regulated Power Supply
The Output had both Constant Current Control and Constant Voltage Control. The CC control is also a Short circuit protection. The Output was protected from outside voltages damaging output circuits even when equipment is switched off. The back panel is a finned anodized black aluminum heat sink with many transistors.

I looked for the circuits to scan them, i could not find it. I made-n-sold quite a few of them years ago. All of them work well even today as i over-rated most components. The cabinet was Steel for EMI-RFI Immunity, it was painted with Stipple Matt Powder Coating, the Cabinet maker had just learnt to give such a finish to his boxes.

Some pages related to power supplies below. Power Design Section