ProtoSpring

ProtoSpring was an experimental project of creating a prototyping expansion board for an existing embedded board, the VIA VAB-600 Springboard. It was designed with expansion in mind, with a bunch of pin-headers accessible on one edge of the board.

The idea being designing an expansion board that attaches to the same set of headers as the VAB-600-A I/O board, and provides power as well as breaks out the GPIO, I2C, and other lines available on those pins.

The schematic is quite straightforward and roughly divided into 3 groups:

1. the 3 input connectors for the appropriate pins
   
2. the breakout headers for power-related, GPIO, and audio pins
   
3. the breadboard connections (power rails and internally connected pins)

Some additional elements include:

• protection polyfuse
  
• voltage stabilization capacitors
  
• power-on indicator LED
  

The board was designed entirely in KiCad (to keep using open source tools). The schematic is quite straightforward, while some of the footprints needed to be created, but there are plenty of examples on how to do those.

Also added a footprint for a SOIC24 pinout to be able to play with some common SMD elements. If I'd do it again, I'd add standard through-hole breakout for this too (easier to solder than to the legs of the ICs)

The total schematic & layout is shared online.

The board was printed using Seeed Studio's FusionPCB service. The end result is quite slick.

The board was assembled by soldering on the components and the sockets. Ready for power-on test. For easier testing, added some pins to the GPIO output so I can probe those lines.

To demonstrate the prototyping capabilities, a quick demo was put together. In that interactive demo the computer screen was divided into 3x3 areas, and as the user moved the mouse on the screen, the mouse position was displayed on a 7-segment display.

Here's the demo video, putting it all together:

It was a very interesting project to learn about multiple things:

• Designing for, and interfacing with an existing hardware
  
• Getting PCBs manufactured
  
• Creating software for a hardware project
  

Will likely develop similar prototyping boards for other embedded boards too, that have accessible I/O pins.

ProtoSpring is now also available on Tindie.

More on this project can be found in its 3-part writeup:

1. Idea and Schematic
2. Schematic revision and PCB
3. Manufacturing and demo