Pcb

Exporting from Proteus ARES to OSH Park

I have recently started to use Proteus ARES for PCB layout. I regularly order boards from OSH Park but there is a fixed file naming convention for uploaded ZIP files.

New PCBs

Today two sets of PCBs arrived from OSH Park. Firstly a breakout board for Kingbright 14 segment LEDs. These are great for very high brightness text display. Secondly a small breakout board for the Maestro A2035-H GPS receiver. This is a capable GPS powered by the SiRFStar IV chipset. It supports NMEA or SPI and can update at 5Hz, which makes it an interesting GPS for sport tracking. I plan on using it for tracking go-karts around an outdoor track.

Hand SMD assembly and frying pan reflow

People often ask how I assemble SMD boards, the video below is sped up to 20x and demonstrates the process. It takes a few minutes to dab some solder paste on each pad, then parts are placed using anti-magnetic tweezers. Finally the whole lot is carefully put into a frying pan and heated quickly over a gas hob. Don’t share the frying pan with anything else - you don’t want to be mixing solder and your sausages!

Breadboard power supply

Right angle corners for PCB traces

There is a lot of myth and misconception about whether right angle (90°), chamfered (45°) or curved PCB traces are “better”. One of the often quoted “facts” is that right angles are bad for signal propagation or radiated RF emissions. I came across a great paper titled “Time and Frequency Domain Analysis for Right Angle Corners on Printed Circuit Board Traces” (PDF link) by Mark I. Montrose which has in-depth analysis and experiments to test this theory out.

BatchPCB

I have previously raved about BatchPCB, a low cost prototyping service run by SparkFun out of the USA. However, it seems that you now can’t select shipping to the UK (and perhaps other parts of Europe) and they don’t seem to be doing too much about it. I emailed a few weeks ago and have received no reply, so all I have to go on is a few posts on their forums which confirm I’m not the only one experiencing the issue.

Updated Eagle library posted

PCB antenna design

One of the circuit boards I’m developing would benefit from an onboard antenna, so I started hunting for design tips. The following three PDF documents do a great job of explaining the basics: Freescale “Compact Integrated Antennas“ Kent Smith “Antennas for low power applications“ Ingecom “V / UHF Antenna Design“ I will update the blog once the circuit board is designed and I have managed to test range and effectiveness.

PCB0002 - LED matrix

Cooking with gas, my first SMD board

My first bunch of boards arrived back from BatchPCB and I’m really impressed.  Great printing for the silkscreen and a really professional looking product.  One of the boards I ordered was a breakout board for the SMD PIC 18F2321, the first surface mount board I have tried.