Yearly Archives: 2011

Decentralized File Version Control

on CAD

I’ve been using Subversion for years to store all of my files. It works well for binary and text files and Subversion is capable of file locking which is an important feature for binary CAD files. I know that lots of people tell you no put binary files in version control software, but it does work if you use the right system. Right now there’s 10’s of gigabytes in my work repository with a working copy that’s about 2GB and there hasn’t been any problems so far. The advantages of using Subversion are:

  • Data security: All your data is in Subversion which means it’s easy to go back in time if necessary. If you setup a separate server you also get redundancy as well since now there’s multiple copies of the data.
  • File locking: This is important for organizations where multiple people work on the same files. By enforcing file locking rules, Subversion makes sure that only 1 person can edit a file at a time. Nothing is more frustrating than having your changes overwritten by someone else.
  • Remote file access: You can easily access Subversion over HTTPS or SSH.

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Second Day with DesignSpark PCB

on CAD, DesignSpark, Tutorial

One of the issues from my first day with DesignSpark PCB was the fact that my titleblock printout didn’t come out as expected. All of the text was shifted down a little and was the wrong size. I did a little more investigation and it turns out that if you use a stroke font instead of a True Type, the alignment doesn’t change when printing. The font size is also the same. However, in order to use stroke fonts you need to declare them in the design technology file for every size and type you intend to use. Even though it looks like you can edit the size of a stroke font by just clicking on it, you can’t.

The next step in my project is to draw the schematic. That was easy – the drawing and placement tools are pretty straight forward. Here’s what I ended up with.

Relay schematic
Relay schematic

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First Day with DesignSpark PCB

on CAD, DesignSpark, Tutorial

This is the first part of a series of tutorials on DesignSpark PCB. The second part is here.

For the last little while I’ve been looking at some of the “free” PCB design tools out there for some open source hardware projects I’m considering. I initially tried Eagle which seems to be the standard “free” package out there because it gives you a limited functionality package for free. I turned it on once and promptly uninstalled it. Sorry, but I just couldn’t get past the user interface. It was completely foreign to me and I’ve used a lot of different packages (PADS, Orcad, Protel, PCAD, Altium Designer, etc). Eagle just felt broken from the first second I tried it, I think mainly because it is so different in ideology from the commercial offerings I’ve tried.

Second on my list is DesignSpark PCB. I tried it and it failed my 5 minute click around the tutorial test. So I sent an email to the DesignSpark people complaining about it. Martin Keenan, the project manager for DesignSpark PCB, replied and gave me some valid reasons to look at it again. So I figured I would but that I would lower my expectations the second time around.

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Chroma 62006P-100-2 Power Supply Review

on Equipment, Review

Chroma ATE has been quietly making really good power supplies for a long time. Today I’m going to talk about 62006P-100-25 which is a 100V 25A power supply with a built in arbitrary function generator. I’ve been using one now for about a year and it’s definitely the best value for the dollar out there now if you need a high end power supply.

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Altium Designer Backwards Annotation Hell

on CAD

I’m tired of searching for reference designators on circuit boards, so I decided to start annotating schematics from the PCB locations. That way all of the designators in sequence are nearby (at least in theory). For example, R1 would be near R2 and R3. The process of reannotating the reference designators on the circuit board and importing the changes back into the schematic is called backwards annotation.

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