Blog update and some musings on EDA tools

Blog updates

Small blog updates this week. The sidebar is now present on all posts, not just the front page for easier navigation. The awesome picture of the Fluke board has now earned its spot as a blog header.I call it the “dancing transistors” banner. Sure beats stock image.

EDA tools choices

In more electronics related news, I’ve been working on a simple board using DipTrace. It’s a new tool for me, so a small simple design/layout and board order will test the waters so to speak. Why DipTrace you might ask, considering I already use high end packages at work such as Mentor Graphics Pads and Altium Designer, or how about Eagle?  Well, for starters my hobby budget is small, and licensing Altium or Pads is well outside of it. I could potentially use Eagle, like everybody else does in the open hardware community, except for two things. Number one, I absolutely could not stand it when I tried it, and number two- the pricing structure is a bit silly. You either get a light version with 2 layers and a lot of limitations for $69, a Standard version for sch+layout for $575 or a professional for $1145. Sure, one could get a hobbyist/non profit version for $169 but first you have to sign a declaration that makes you liable the moment you design a board and sell a couple. Meh, not good enough. And at every level of pricing, there is still a board size limit. Enter DipTrace. The  free/noncommercial license allows 500 pins and 2 layers. For a commercial version, Standard version with 1000 pins and 4 layers is only $345 and the full version with no limitations is $695. There is also an intermediate version that’s $495 and goes up to 6 layers. That to me seems like a much nicer upgrade path should I ever want to design and sell products. The fact that you could just pay the difference in price to go up the feature ladder is very smart as well.

Now back to work. Pictures/board info coming soon

Sinclair PDM35 multimeter teardown

Another Hamfest find is the Sinclair Radionics PDM 35 digital multimeter. Having grown up with ZX Sinclair Spectrum clone, and reading a lot about Sir Clive Sinclair and his creation I wasn’t about to walk by this. If the look of it is a bit calculator-like, that’s because they actually reused a calculator enclosure! This was a  cheap model, selling for 33 pounds in the 70-s and 80s

It's a calcu-err-meter

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Appnote: AN1258 Op Amp Precision Design: PCB Layout Techniques

Microchip has just posted a pretty good appnote ” Op Amp Precision Design: PCB Layout Techniques”

“This application note covers Printed Circuit Board  (PCB) effects encountered in high (DC) precision op  amp circuits. It provides techniques for improving the
performance, giving more flexibility in solving a given  design problem. It demonstrates one important factor necessary to convert a good schematic into a working precision design”

 

Upgrading an electric lawn mower to lithium batteries

Part 1- getting the platform

This all started when we bought a house and it came with a bit of grass. And grass wanted to grow and had to be cut. Initially I paid a lawn service to come and cut it, but they kept cutting bits I did not want them to. So I looked at the annual amount I was paying them and decided that would be my budget for a mower. Being an electrical guy, I very much dislike all things gas powered, stinky and noisy. So the absolute requirement was for the mower to be electric.  I looked around a bit, and my choices seemed to be a bunch of no-name large box store mowers running Lead Acid batteries or corded, a few exotic European market-only Lithium powered mowers or making my own. I picked neither  Continue reading

Reviving an IBM ThinkPad X31

This is an old repair I did a while ago and posted on thinkpads forums.  Reposting here to put it all under one roof. We have quite a few IBM Thinkpads X31 in the family. They are built like a tank and work well enough to keep using them despite 2003-2004 datecodes. One day two of them started exhibiting identical symptoms- they would just refuse to turn on. No lights, fans or other signs of life. Luckily I stumbled on a schematic on the web, so that was a good starting point.

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