Arduino shields come in hand from time to time when you want to prototype some hardware.
As I had a Grove Base Shield from Seeed Studios I decided to give it a try to hack it together with one of our STKs and it actually turns out that this is possible.
The unfortunate candidate to receive surgery this time, was a Mighty Gecko WSTK. All the newer starter kits have the correct spacing between the rows, it was just a matter of getting the pin mapping right. This is what I ended up with. The green dots are where headers will be added, and the red stars are pins on the Arduino shield that will have to be cut:
So I started by cutting the top three pins on the short side (NC, IOREF and RST). I also removed the 5V pin, as the shield will only communicate using 3.3V:
Then you can see that the GND pins does not align properly. This was solved by grounding the pin next to it:
As I have just created a Connected Coffe Machine and had a Grove LED Bar lying around I thought I'd upgrade the receiver with a nice LED bar, going from all green to full red when the coffee machine needs to be emptied. The code I used can be found here: https://github.com/SiliconLabsLabs/ConnectedCoffee
Summary: You can use digital pins 0-7 and analog pins 0-5 on 3V Arduino shields with the Silicon Labs (W)STKs:
Thanks for good article!