Userspace Arduino:cape ideas 2
Ideas for hardware for the Beaglebone Black, which can be used to interface with peripherals like SPI, I2C etc.
It would be advantageous to go with devices which have existing Arduino sketches, since they are more likely to be widely used and tested with. A quick check at a local vendor revealed the following common sensors/devices being used with the I2C bus. Note: All of them work on a 3.3V interface and they almost always require only the 2 I2C pins for communication.
- BMP085: Barometric Pressure Sensor Module, a breakout board from Sparkfun. The libraries are available here . Looking at the datasheet , we can see some pretty basic protocols for reading from and writing to the onboard registers using the I2C bus.
- MPU-9150: Accelerometer + Gyro + Magnetometer with breakout board available at . A sketch is already available .
- DS3231, DS1331 are very popular RTC chips with nice breakout boards from Adafruit (the ChronoDot Ultra-Precise Real Time Clock). The added advantage here would be the development/testing of the time library Time library. This can infact be used for time-keeping on the Beaglebone. Sample sketch also available here 
- SCP1000: Barometric Pressure Sensor Module
- SHARP Memory Display: A very cool display which is a cross between an e-ink display and an LCD.
- PN532 NFC/RFID: A popular (I have this one!) RFID chip with breakout board which is compatible with several protocols. Could be really cool, except for the part where an antenna might need to be embedded in the cape.
- SD Card Audio: A great way to get audio output from the Beaglebone using one (or two) PWM outputs.