Repair Kopitiam specialty electrical tools (Part 2): Short Circuit Limiter

Reading Time: 12 minutes

If you have not read the previous post (Part 1) on this subject, I encourage you but it is not mandatory to do so before reading this post. I’ll still go through the fundamentals in this post. If you just want to see the raw technical details, the schematic and code of this project have been open-sourced here.

Post Objective

To show why did I build this and how it works plus the issues faced.

The clean case hides the complexity within.

Background

I’m a regular volunteer in the social initiative called Repair Kopitiam (RK) started by Sustainable Living Lab (SL2). On a monthly basis, we teach Singapore residents how to repair their household electrical appliances, fabrics and furniture. Our volunteers are also called repair coaches.

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CV of Dating Failures

Reading Time: 7 minutes

Recently I wrote a blog post on my failures based on the concept of the “CV of Failures”. Inside, it contains key things or events I failed in.

I got a comment from a friend that it was still the “easy” stuff with only one line about my 3-year relationship that ended years back. Although the CV of Failures is largely career/skills based, the spirit of that concept is transferable. I missed the elephant in the room which is about relationship (attempt) failures.

Sometime back also, my female colleague once remarked “You are not even trying”. It was at that point I realised that attempts are rarely talked about. I mean people occasionally talk about their failed relationship(s) (including yours truly) in 1:1 or small groups. Much rarer are about failed attempts to start as that is considered quite embarrassing. Attempts specifically applies to men as ladies rarely make the move. (Assuming a typical heterosexual narrative here)  If typical failures are already taboo, relationship failures on the edge of being off-limits, then talking about failed attempts in asking ladies out must be hell.

So let me go to hell this time to break what we deem to be a hugely embarrassing topic. I’ll not mention all the cases just the more recent ones that happened in the last few years. I see myself as quite systematic so I’ll mention the qualities I saw in the lady to make me ask her out, how the encounter roughly went and what I learned from it.

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Book Review: Neither Civil Nor Servant (The Philip Yeo Story)

Reading Time: 9 minutes

“life sciences graduates are only fit to wash test tubes” this statement I heard more than a decade ago was the first time I knew of this guy called Philip Yeo. Then chairman of Agency for Science, Technology and Research (A*Star), it caused quite a ruckus I believe in Singapore at the time where there was a strong push by the government into the bio-medical field.

That line partly factored in my decision against taking up a triple-science (Physics, Chemistry, Biology) subject combination in secondary school. I opted for Physics and Chemistry only.

When I recently heard from online sources of this biography of the man himself “Neither Civil Nor Servant”, I was intrigued. I admit I did not know much of this supposedly very “notorious” Singaporean civil servant. So when existence of this book came to me, I decided I had to read it.

So here is my take of reviewing this book!

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CV of Failures

Reading Time: 4 minutes

I recently chanced upon the concept of CV of Failures from Princeton Professor Johannes Haushofer. He wasn’t the first to do so but I guess the first that actually popularised it. Inspired by his example, I decided to write the following post. After all, it is not just success that defines us but the failures as well.

I’m obviously not as academically-credentialed as this Princeton Prof so I’ll put up key events that happened in my life in both school and outside.

For obvious reasons, this will be an evergreen post that will be constantly updated.


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A Science Project: Bringing the Covox Speech Thing to 2017

Reading Time: 9 minutes

The Covox Speech Thing (CST) was a sound card released in 1986 by Covox, Inc to enable computers with parallel ports to have sound capability. Unlike modern machines, proper sound support was not a given on computers in that era and the Soundblaster by Creative has yet to be released.

As you will see later, the design is rather simple so I decided to revisit this old piece of hardware and see if it is possible to get it working on modern systems.

My remake of the Covox Speech Thing with a self-wrote media player software.

Video of everything in action

Video of the talk I gave about this subject at Hackware v2.6.

Slides of the talk I gave

If you are in a hurry to obtain the raw schematics and code, everything can be found in the following links.

Verified designs: Media player code, pure Covox clone, Covox clone with amplifier

Untested work: USB to 8-bit adapter, Covox clone with amplifier and USB 8-bit adapter

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A Science Project: Windows for Workgroups 3.11 on vintage and modern hardware in 2016

Reading Time: 23 minutes

(This is a long 5600+ words post, I recommend reading this from a tablet or computer)

Windows for Workgroups 3.11 (WFW3.11) was an operating system (OS) released by Microsoft in August 1993 and ended support in December 2001. It is part of a series of OSes released by Microsoft at that time so it is common for people to refer to it as part of Windows 3.1x (Win3.1). The specific history behind its name and version number and be found on its Wikipedia article. Here is a brief list of first-impressions I have if I were to describe this OS.

  1. First Windows OS to have practical (installable) networking capabilities
  2. Last one to not have a Start Menu and legacy interface before Windows 95
  3. Last OS to require DOS as an initial install
  4. Last 16-bit OS

wfw-first

Here is a teaser screenshot showing that I managed to get WFW3.11 installed on a “modern” 2009 Thinkpad T400 with networking capabilities. Recognise some familiar applications there?

My talk on this subject

I gave a talk on this project at Hackware v2.2 on 7 September. Here are the slides and video.

Demo video

About 8 minutes of video for the vintage computing buffs. This shows the results of my work.

Why install WFW3.11?

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(Partial) Reverse Engineering the NDP 2016 LED Wristband

Reading Time: 5 minutes

The Singapore National Day Parade (NDP 2016) happened on 9 August 2016 to celebrate its 51st birthday. For those who had the opportunity to attend the actual parade or its previews/rehearsals, they will also get to receive a funpack where one of the items will be a wearable LED band made by a company called Pixmob.

ndp2016-re-wristband

This band receives infrared(IR) signals from the organisers and then displays the LED colour of their choosing. There is also an onboard accelerometer. After the event when the IR signals disappear, the (single-axis I believe) accelerometer will cause the Red LED to light up when a shock is detected.

Here are the slides and the talk video on this subject I gave at Hackware v2.1.

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Repair Kopitiam specialty electrical tools

Reading Time: 13 minutes

I’m part of this voluntary social initiative called Repair Kopitiam (RK) started by the social enterprise Sustainable Living Lab. On a monthly basis, we teach Singapore residents how to repair their household electrical appliances, fabrics and furniture. Our volunteers are called repair coaches. This initiative is similar to Repair Cafes which originated in Europe. My area of speciality is of course in the electrical appliance department.

This post is however not about the intricate details of volunteering, it will be about the special electrical tools I have developed in the course of my volunteering in response to certain unique issues faced by the RK team.

A literally high-level view of the tools I developed.

rk-equip-equipment-overview-small

Here are the slides and video of the talk I gave at Hackware v2.0 about these tools.

The problems

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