Primarily, Bluetooth connects wireless headsets to cell phones. But it also can be used in a wide range of serial I/O applications for monitoring or controlling external devices. For example, connectBlue AB’s OBI411 drop-in Bluetooth module lets you exchange data over a standard serial link for industrial applications. It also lets you easily read or write digital I/O signals or read analog I/O signals wirelessly (see the figure).

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“The new Bluetooth module makes data handling much easier for our industrial customers when they look to remote-control any machine, read data presented in an iPhone/iPad, or read and transmit data to a server via a mobile phone,” says Rolf Nilsson, CEO of connectBlue.

The OBI411 supports Android-based phones and Apple’s iPhone via an external Apple authentication chip. The I/O software can also be downloaded as firmware for the OBS414 Bluetooth module, which has the Apple authentication chip built in.

Furthermore, the OBI411 implements wireless I/O functionality with up to 16 digital I/O signals and four analog 10-bit analog-to-digital converters (ADCs) on each side of the module with latency at only 5 to 8 ms. The Bluetooth module supports the control or reading of I/O signals from an Apple iPhone, iPod touch, or iPad as well.

The module uses a Bluetooth 2.1 + EDR (extended data rate) radio. The output power is Class 1 or +4 dBm with a receive sensitivity of –4 dBm, giving the OBI411 a maximum range of about 150 meters depending on the antenna and line of sight path. The OBI411 also supports the Bluetooth Generic Access Profile (GAP) and Serial Port Profile (SPP), as well as standard UART data rates from 1200 bits/s to 1.36 Mbits/s. Control is by standard AT commands (see “What Are AT Commands?”).

Additional features include support for multipoint/multidrop functionality with up to three slaves possible. The module is also available with either internal or external antenna. And, the OBI411 is Bluetooth qualified and approved according to Europe, U.S., and Canada regulations as well as compliant with electromagnetic compatibility (EMC), safety, and medical standards.

The connectBlue AB OBI411 Bluetooth I/O module makes data handling easier in industrial applications, but it also supports analog I/O as well as Android devices and Apple’s iPhone, iPod touch, and iPad.

The module measures 16 by 36 by 3 mm, and dc power can be from 3 to 6 V with a maximum 25.1-mA current draw while transmitting.

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