Author Archives: daqq

New method for measuring lots of resistors using very few wires - part 3 - a simple measurement device

Posted on 2017/08/22 by daqq

The hardware implementation The previous bits of the article ( part 1 and part 2 ) described the core concepts of this measurement and the theory behind it. The actual measurement device - the measurement system is pretty simple when … Continue reading →

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Davids bile giveaway - Subscription? No, thanks.

Posted on 2017/08/19 by daqq

Warning: NSFW language. So, Autodesk bought Eagle. This in and of itself would not necessarily be bad news - Eagle has been in need of some improvements for some time, and occasionally, when a bigger company assimilates a smaller company … Continue reading →

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New method for measuring lots of resistors using very few wires - part 2 - Theory

Posted on 2017/08/13 by daqq

The Matrix Continuing from part 1 the matrix form used needs to be described. If you need a quick "tutorial" in systems of linear equations, take a look at this text I wrote. First, the vector of the unknowns - … Continue reading →

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New method for measuring lots of resistors using very few wires - part 1 - Theory + intro

Posted on 2017/08/13 by daqq

Introduction This article describes a new method of measuring a lot of resistors using a low amount of wires and a lot of math. The resistors can be any kind of resistors, thermistors or other resistive sensors. It can be … Continue reading →

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GPIO abuse - sourcing and measuring at the same time

Posted on 2017/05/26 by daqq

The GPIO (General Purpose Input Output) pins are the pins of a microcontroller (or other device) that can connect the device to the rest of the world, without having a particular dedicated function. In contrast to pins dedicated to a … Continue reading →

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Overdetermined system of linear equations

Posted on 2017/02/10 by daqq

Introduction This text is a quick post that should give a quick explanation on (overdetermined) systems of linear equations, particularly their matrix form. It is for an upcoming article that deals quite a lot with these systems. Warning: Please note … Continue reading →

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Repair/teardown - FlexiScale weight and calculator scale

Posted on 2017/01/29 by daqq

I love going to the flea market - you find all sorts of fun stuff, bargains, trash and the occasional treasure that is being sold for next to nothing. This posts fits into the 'fun stuff' area - while at … Continue reading →

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L110 METRA Blansko resistance decade box

Posted on 2017/01/22 by daqq

Recently I got a L110 resistance decade box made by METRA Blansko, in former Czechoslovakia. Unfortunately something was rattling inside, so I had a quick look inside to remove the offending part - it was a small metal nut that … Continue reading →

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Circuit Cellar publication - a new method for measuring resistors!

Posted on 2016/08/30 by daqq

Dear readers, After lots of work, waiting and experimenting, I have completed a text that I have sent to Circuit Cellar and they have agreed to publish it. The article deals with a new measurement technique designed to measure lots … Continue reading →

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HP 9000 Superdome utilities board ( A6475-60201 ; UGUY5-500 ) high res scan + guesswork

Posted on 2015/03/17 by daqq

While on a buying frenzy at a local radioamatuer gettogether (Holice 2014) I saw an interesting looking PCB - apparently taken from some kind of older HP system, it had some very nice oscillators (500, 525, 100, 126 MHz), some … Continue reading →

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