Sunday, April 7, 2013

Use (Some) Arduino Shields on Your Raspberry Pi

The "Raspberry Pi to Arduino shields connection bridge" is a Raspberry Pi add-on allowing you to use some of the shields, boards and modules designed for Arduino on a Raspberry Pi. It includes also the possibility of connecting digital and analog sensors, using the same pinout of Arduino but with the power and capabilities of a Raspberry Pi.
The "Raspberry Pi to Arduino shields connection bridge" board on top of a Raspberry Pi computer
To allow for software programming, cooking-hacks.com has written the arduPi C/C++ library allowing a Raspberry Pi to use the same code used in Arduino. To do so, they implemented conversion functions to control the hardware in the same way as in Arduino the same I/O interfaces: i2CSPIUARTanalogdigital, on a Raspberry Pi. What may be done with the shield along with the arduPi library:
 

I have used the word some when the site uses any.  Buried down on the page is this warning:
WARNING: GPIO voltage levels are 3.3 V and are not 5 V tolerant. There is no over-voltage protection on the board. Digital inputs use a 3V3 logic level and are not tolerant of 5V levels, such as you might find on a 5V powered Arduino.
Extreme caution when working with GPIO, you may damage your Raspberry Pi, your equipment and potentially yourself and others.

As most shields have 5 volt signals, this could be a large limitation.  The number of 3.3 volt shields is expected to grow, albeit slowly, with hardware using sensing to be compatible with hardware like the new Arduino Due.

I like the Bee socket.  Many types of hardware have been made in this form factor - usually at 3.3 volts like the XBee.

At 40 euros, it is rather overpriced for the US market.