Tuesday, 8 July 2014

10 Years On

DIY Trailer LED Lights

About 10 years ago I built a pair of LED trailer lamps for my Father In Law. This was back when LED lights were stupidly expensive - and as luck would have it I had access to some high brightness samples. 

Anyway, the lights served their time in the harsh conditions of the Riverland and the plastic lenses finally turned more opaque than useful. 

After replacing with a set of lamps off eBay for less than $40 I thought I'd share what they look like now. 

Monday, 7 July 2014

Keeping Things Isolated

Why Use Isolated Power Supplies

With most hobby electronics, all your system parts tend to operate from a common ground.  This makes things easy to understand, as you just measure what a device is 'doing' with respect to ground, and you can make things happen in your design.

For example, you can decide that 5V above ground is logic high, and if your micro sees that level on a pin ou can turn on a light. Or if it's an analogue value of 3.2 volts you might think your room is warm enough and decide to turn off your heater.

Sometimes you might here this referred to as an 'absolute value' above ground.

Makes sense.

But sometimes, you don't want to know what the difference is between two points that are different to ground.


Monday, 30 June 2014

More on Alarm Panel Interfacing

I've Been Busy...

I haven't had the chance to update things for a while, but for those interested, I'd like to share some build pictures of my Alarm Interface.  And yes, it's working and in service, with a nice programming GUI. (Links at the end - code will be up "soon").

Teaser Render!

Measure Twice, Cut Once, Get a New Ruler....

History Repeats

With past projects, I've made some mistakes that are common to a lot of projects.  Who hasn't mixed up D+ and D- on a 485 driver?

One thing I've added to my workflow is using excel to help build my new packages.  In Altium you can copy pin information from a pdf into a table, massage it as needed and then pate it onto Altium.  I've configured 100 pin devices like this in a lot less time it would take to edit them one by one.

Friday, 2 May 2014

Closing the KiCAD Gaps

Imports and Persistence

As discussed before, I'd decided to try KiCAD for the first time and the approach I took as to port an existing design, in this case EEVBlog's uCurrent.

To recap, I'd produce a schematic that still needed it's annotation and part values updated, and I'd also imported the Altium PCB files into KiCAD, with an Altium to P-CAD conversion as an intermediate step.

Wednesday, 16 April 2014

New Boards!

New Boards

My next bunch of boards from Seeed studio have arrived.  Here's some shots of parting out the prototypes from 10 x 15 cm panels.

Build and test info coming... as soon as I build and test.

Tuesday, 15 April 2014

What's All This KiCAD Stuff, Anyhow?

Going Open Source CAD

As can be seem from various post's here, I'm an Altium user.  I'm lucky enough to have access to it work, and I've been using it since it was good old Autotrax for DOS.   Yes, I'm that old....

For work that's fine but with my home projects I'm keen on sharing these as Open Source Hardware and releasing designs in Altium goes against the grain here - the community prefers that you share using open source tools.

So with this in mind, I decided to take the plunge and try KiCAD.  My following thoughts will be comparisons between 'what I know' about Altium and what my impression are about KiCAD and I fear it will be far from fair.  Altium does set the bar, and thus my expectations of what a PCB CAD tool can do, pretty high...

It Can Be Done!

And besides, I need something to do while I wait for my next revision of Alarm PCBs to land....