MiniPiio Relay2 Board v0.10

September 7, 2012

** UPDATE: You can get these boards at tindie.com in the DTronixs store

I meant to post this a few weeks back but holidays etc. got in the way, so here it is now.

So here we have a simple two relay DPCO board. Either of the relays can be selected from 8 off the GPIO pins from the Raspberry Pi expansion header.

Circuit schematic is here

and here it is on a Raspberry Pi


RS232 Breakout Board for Raspberry-Pi

January 25, 2012

The Raspberry-Pi¬† will be with us soon. In the mean time I would like to share a little RS232 breakout PCB I”ve designed for use with the RPi.

It”s a simple RS232 circuit using a MAX3232 chip connected to the UART Rx and Tx of the RPi.

I”ve not included any mounting holes as I don”t know if the final RPi will have any, although I hope to add some for the next version. It was pointed out on the RPi forums that the RPi’s 3.3v supply is limited to 50mA so I may add a 3.3V regulator to the circuit. A MCP1703 from Microchip was recommended, The addition current from an additional¬† 3.3V regulator will useful if you want to use the prototyping area on the breakout board. That said the RPi’s 3.3V at 50mA is enough for the MAX3232 by itself.

The design was done in DesignSpark PCB and I”ll post the design files and gerbers in due course and I expect to get some finished PCB”s after the Chinese New Year

Initial schematic for v0.10 is here


DesignSpark PCB to Google SketchUp in 3D

June 29, 2011

DesignSpark have released a small conversion program which will take a DesignSpark PCB’s 3D IDF output and convert it into a format Google SketchUp can import.

To make the most of this you need to enter height data for the components on your PCB. But this is pretty easy, you need open the property dialog for a component either on the schematic or layout and select “values” and edit the “component height” value. If you’re doing this on the schematic you’ll need to forward annotate the design changes to the PCB layout before outputting the PCB as a IDF model.

At the moment it just gives you a simple “skyscraper” 3D model, but even this is useful for checking for space clashes when you come to integrate your PCB design into a mechanical design.

“PCB Converter for SketchUp allows designers to import Intermediate Data Format (IDF) files into Google SketchUp. The new module adds a 3D CAD back-end capability to PCB design tools and takes SketchUp into the electronic product design domain.”


New Schematic/PCB Design software in town

July 9, 2010

DesignSpark (something to do with RS Components) are giving away a free Schematic Capture and PCB package. I’m guessing its RS Components response to its arch rivals Farnell recently buying Cadsoft, the authors of the hugely popular Eagle CAD software.

Once you download DesignSpark PCB you’ll find it looks and feels the same as NumberOne System Easy-PC. That’s because it is, DesignSpark have gotten NumberOne to sell them their software and re-badged it as DesignSpark PCB.

Comparing it to EagleCAD would take an entire blog entry on its own but the main differences between the free versions are:

DesignSpark PCB:

  • no restrictions to the size of PCB board (I think its drawing area is up to 1.0m by 1.0m (39″ by 39″))
  • no restrictions (I think it allows up to 14) on the number of signal layers can be used.
  • no restrictions (I think it allows up to 99) to the number on schematic sheets per project
  • no commercial restrictions (non mentioned on web site)

EAGLE Light Edition:

  • The usable board area is limited to 100 x 80 mm (4″ x 3.2″).
  • Only two signal layers can be used (Top and Bottom).
  • The schematic editor can only create one sheet.
  • non-profit only licence (you must buy it if you earn (or save) money by using the Freeware version of EAGLE Light)

Now all this sounds great, but it’s a shame the DesignSpark libraries are incompatible with existing Easy-PC libraries. I’ve been using Easy-PC for 8 years and would have liked to share some of my designs through DesignSpark PCB, but NumberOne still have a business to run so it makes sense not to give away too much of the family silver.

Another thing to mention, is that importing from EagleCAD is not as straight forward as the blurb would suggest. You need a copy of EagleCAD and have to run an EagleCAD macro while EagleCAD is running to output the desired design data into a ASCII formatted file. Once this is done you can import the intermediate EagleCAD schematic, PCB or library file into DesignSpark PCB.