Note: The nRF8001 sends out packets of data, 20 bytes at time. Keep this in mind if you want to send a lot of data it will be packetized into chunks of 20. You can of course send less than 20 bytes.

Exploring Mobile Interface

After initial setup and software tests, I was able to explore the Adafruit developer smart phone application found in the android market, “BlueFruit LE”. (APK file linked here) 

Much like Serial you can use the .write and .print functions allow us to send data out to the connected device:

Features included in Bluefruit LE App

Info

Displays MAC address and other relevant Device Information

UART

The “UART” function allows a basic text message interface from smartphone to the Arduino Series monitor. However, after testing it was apparent that although the application allows infinite characters of transmission, the messages are broken apart into 20 character fragments due to the data transmitting capabilities of the bluetooth chip.

Pin I/O

The Pin I/O section of the mobile phone application allows the user to control input and output of pins (both analog and digital) on Arduino shield. However, this particular function required significant code modification in order to allow functionality on Android enabled devices. Once the code is finalized it will be published and linked here. In order to display this faciniating functionality a small demo was contructed in order to deminstate the smart phone interfaces capabilities. 

This section of the Bluefruit LE application appears to be very useful, unstable and will require further explanation.

Controller

Streams sensor data from smart phone sensors (Quaternion (6-axis accelerometer), Accelerometer, Gyro, Magnetometer, Location)

Beacon

Puts smartphone in a state to receive pop-up text messages from serial monitor up to 20 characters  

Neopixel

Needs further exploration.

Conclusions

**Initial testing of connectivity shows an approximate range of 20 feet for reliable signal strength.**

After initial testing it would appear that  the Pin I/O will have the most practical capabilities and research of its functionality will continue. 

– Tom DeBell, Beginning Researcher Support Program researcher

Initial setup for this project began early this week starting with soldering header pins onto the nRF08001 Bluetooth LE (Low Energy) breakout board so that a physical connection could be made with an Arduino Uno module to begin testing. A valuable resource that helped getting started can be found at adafruit.

The wiring of the Bluetooth board to the arduino was done as follows. 

Wiring Schematic

• VIN connects to the Arduino 5V pin (Red Wire)
• GND connects to Arduino ground (Black Wire)
• SCK connects to SPI clock.  (Blue Wire)
  On Arduino Uno/Duemilanove/328-based, thats Digital 13. 
  On Mega’s, its Digital 52 and on
  Leonardo/Micro its ICSP-3 (See SPI Connections for more details)
• MISO connects to SPI MISO. (Yellow Wire)
  On Arduino Uno/Duemilanove/328-based, thats Digital 12. 
  On Mega’s, its Digital 50 and on
  Leonardo/Micro its ICSP-1 (See SPI Connections for more details)
• MOSI connects to SPI MOSI. (Teal Wire)
  On Arduino Uno/Duemilanove/328-based, thats Digital 11. 
  On Mega’s, its Digital 51 and on
  Leonardo/Micro its ICSP-4 (See SPI Connections for more details)
• REQ connects to our SPI Chip Select pin. We’ll be using Digital 10 but you can later change this to any pin. (Grey Wire)
• RST connects to Digital 9 – this is for resetting the board when we start up, you can later change this to any pin. (Orange Wire)
• RDY is the interrupt out from the nRF8001, we’ll connect to Digital 2 but be aware that if you want to change it, it must connect to an interrupt capable pin (see this Arduino page for which pins are interrupt-capable. Digital 2 is OK on Uno/Leonardo/Micro/Mega/etc.) (White Wire)
• Note: Wire colors refer to first wiring diegram

Initial Testing

After wiring was completed testing of bluetooth transmissions and functionality began with positive initial results. By running a sample arduino code found on GitHub we were able to communicate to the arduino via the “Bluefruit LE” android application and likewise was able to transmit data from the command line of the arduino workspace directly to a smart phone via the bluetooth module.  Further Testing will contiuno next week.

– Tom DeBell, Beginning Researcher Support Program researcher