The BAL, a development board for Bluetooth Audio devices. With BAL you can do a number of things, ranging from simply connecting your phone or laptop and streaming high quality, pop free, stereo audio from it, to more complex features like connecting a micro-controller, and controlling the connected device via Bluetooth. With an on-board pre-amplifier and pop filter, you can plug in headphones and listen right away, at CD quality.

Now includes Arduino library for RN52 development! Click here to find out more

For more information about BAL visit the product page on our website.

Click here to go to the full BAL manual.

Features

• Easy to use 3.5mm audio jack output
• Customisable Bluetooth device name
• Fully featured Arduino library for the RN52 chip
• Connectable from any Bluetooth enabled device
• FTDI connector to interface with the BAL from the computer
• GPIO all broken out
• SPI and PCM lines also broken out
• On-board pre-amplifier and pop filter
• Barrel jack input
• USB Micro-B power source
• USB Firmware upgradable
• Microphone input
• Supports various Bluetooth profiles, it's not all about audio!

Specifications

For all you specs nerds out there!

Supply:

• 3.3V-16V Input
• Maximum Current: 1A
• Typical Current: <500mA
• Good quality noise rejection/filtering from supply to output

For the main chip - the RN52 from Microchip:

• Bluetooth 3.0, class 2 device
• 3Mbps Data Rate (Maximum)
• Operational range of 10m
• -85dBm Sensitivity
• 2.4 - 2.48GHz Frequency
• 44.1KHz Output DAC (CD quality)
• 44.1KHz Input ADC
• Supports A2DP, AVRCP, HFP, HSP, SPP and iAP Bluetooth profiles
• ~150ms typical latency - this spec is not from the RN52 datasheet, as one was not listed, but is our typical experience. Playing local files gives lower latency figures than this, usually unnoticeable, whereas streaming from (for example) YouTube gives mildly noticeable latency.

For the amplifier and pop filter - DRV602 from Texas Instruments:

• Flat frequency response (20Hz - 20KHz)
• Signal to Noise ratio of 102dB
• 2Vrms output into a 2k5Ω Load
• 15μVrms noise output voltage
• Audio Streaming

The simplest function of the BAL is to be used as an audio streaming device, which allows you to convert your standard amplifier/home stereo set-up into a wireless entertainment device. Connecting to the BAL from any of your devices is as easy as you would expect.

Arduino Library

Doayee have written an Arduino Library for the RN52 chip on the BAL to make implementation of the BAL even easier. For more information visit: http://doayee.co.uk/bal/library

Here is a video from our Kickstarter campaign: