RS-232 Serial Adapter for Android Devices

ACCESSThe ANDROID-232 is a USB serial interface board that enables you to control legacy RS-232 devices from your Android devices. The board is well suited for POS, gaming systems, retail, hospitality, automation, kiosks, defense industries, lighting, or any other application requiring the connection of RS-232 serial devices to an Android-compatible system.

The ANDROID-232 uses the Android Open Accessory protocol to “convince” an Android device that its on-board USB port (normally limited to USB slave or OTG modes) is actually an RS-232 port. This two-way data port enables external hardware to control the Android unit or the Android unit to control external hardware.

The ANDROID-232’s key features include an Android USB 2.0 full-speed host-to-industry-standard RS-232 DB9M serial port; support for a UART interface with RX, TX, RTS, and CTS; a 5,512-byte RX buffer size; a 256-byte TX buffer size; ±15-kV ESD protection on USB data lines and all RS-232 signals; status and fault LEDs including external power, charging status, and USB status; a Type-A USB connector; a latching 5-V external power input connector with an external regulated power supply; a –40°C-to-85°C standard industrial operating temperature; and RoHS compliance.

The board includes an Android sample program with source code. This program enables you to verify proper operation of the ANDROID-232 device, including sending and receiving RS-232 data. The ANDROID-232’s Python test program can cooperate with the Android sample program to verify proper receipt of transmitted data.

The ANDROID-232 costs $139.

ACCES I/O Products, Inc.
www.accesio.com

Client Profile: Invenscience LC

Invenscience2340 South Heritage Drive, Suite I
Nibley UT, 84321

CONTACT: Collin Lewis, sales@invenscience.com
invenscience.com

EMBEDDED PRODUCTS: Torxis Servos and various servo controllers

FEATURED PRODUCT: Invenscience features a wide range of unique servo controllers that generate the PWM signal for general RC servomotors of all brands and Torxis Servos. (The Simple Slider Servo Controller is pictured.) Included in this lineup are:

  • Gamer joystick controllers
  • Conventional joystick controllers
  • Equalizer-style slider controllers
  • Android device Bluetooth controllers

All of these controllers provide power and the radio control (RC) PWM signal necessary to make servos move without any programming effort.

EXCLUSIVE OFFER: Use the promo code “CC2014” to receive a 10% discount on all purchases through March 31, 2014.

Circuit Cellar prides itself on presenting readers with information about innovative companies, organizations, products, and services relating to embedded technologies. This space is where Circuit Cellar enables clients to present readers useful information, special deals, and more.

Turn Your Android Device into an Application Tool

A few years ago, the Android Open Accessory initiative was announced with the aim of making it easier for hardware manufacturers to create accessories that work with every Android device. Future Technology Devices International (FTDI) joined the initiative and last year introduced the FTD311D multi-interface Android host IC. The goal was to enable engineers and designers to make effective use of tablets and smartphones with the Android OS, according to Circuit Cellar columnist Jeff Bachiochi.

The FTD311D “provides an instant bridge from an Android USB port(B) to peripheral hardware over general purpose input-out (GPIO), UART, PWM, I2C Master, SPI Slave, or SPI Master interfaces,” Bachiochi says.

In the magazine’s December issue Bachiochi takes a comprehensive look at the USB Android host IC and how it works. By the end of his article, readers will have learned quite a bit about how to use FTDI’s apps and the FT311D chip to turn an Android device into their own I/0 tool.

Bachiochi used the SPI Master demo to read key presses and set LED states on this SPI slave 16-key touch panel.

Bachiochi used the SPI Master demo to read key presses and set LED states on this SPI slave 16-key touch panel.

Here is how Bachiochi describes the FT311D and its advantages:

The FT311D is a full-speed USB host targeted at providing access to peripheral hardware from a USB port on an Android device. While an Android device can be a USB host, many are mobile devices with limited power. For now, these On-The-Go (OTG) ports will be USB devices only (i.e., they can only connect to a USB host as a USB device).

Since the USB host is responsible for supplying power to a USB peripheral device, it would be bad design practice to enable a USB peripheral to drain an Android mobile device’s energy. Consequently, the FT311D takes on the task of USB host, eliminating any draw on the Android device’s battery.

All Android devices from V3.1 (Honeycomb) support the Android Open Accessory Mode (AOAM). The AOAM is the complete reverse of the conventional USB interconnect. This game-changing approach to attaching peripherals enables three key advantages. First, there is no need to develop special drivers for the hardware; second, it is unnecessary to root devices to alter permissions for loading drivers; and third, the peripheral provides the power to use the port, which ensures the mobile device battery is not quickly drained by the external hardware being attached.

Since the FT311D handles the entire USB host protocol, USB-specific firmware programming isn’t required. As the host, the FT311D must inquire whether the connected device supports the AOAM. If so, it will operate as an Open Accessory Mode device with one USB BULK IN endpoint and one USB BULK OUT endpoint (as well as the control endpoint.) This interface will be a full-speed (12-Mbps) USB enabling data transfer in and out.

The AOAM USB host has a set of string descriptors the Android OS is capable of reading. These strings are (user) associated with an Android OS application. The Android then uses these strings to automatically start the application when the hardware is connected. The FT311D is configured for one of its multiple interfaces via configuration inputs at power-up. Each configuration will supply the Android device with a unique set of string descriptors, therefore enabling different applications to run, depending on its setup.

The FT311D’s configuration determines whether each application will have access to several user interface APIs that are specific to each configuration.

The article goes on to examine the various interfaces in detail and to describe a number of demo projects, including a multimeter.

Many of Bachiochi's projects use printable ASCII text commands and replies. This enables a serial terminal to become a handy user I/O device. This current probe circuit outputs its measurements in ASCII-printable text.

Many of Bachiochi’s projects use printable ASCII text commands and replies. This enables a serial terminal to become a handy user I/O device. This current probe circuit outputs its measurements in ASCII-printable text.

Multimeters are great tools. They have portability that enables them to be brought to wherever a measurement must be made. An Android device has this same ability. Since applications can be written for these devices, they make a great portable application tool. Until the AOAM’s release, there was no way for these devices to be connected to any external circuitry and used as an effective tool.

I think FTDI has bridged this gap nicely. It provided a great interface chip that can be added to any circuit that will enable an Android device to serve as an effective user I/O device. I’ve used the chip to quickly interface with some technology to discover its potential or just test its abilities. But I’m sure you are already thinking about the other potential uses for this connection.

Bachiochi is curious to hear from readers about their own ideas.

If you think the AOAM has future potential, but you want to know what’s involved with writing Android applications for a specific purpose, send me an e-mail and I’ll add this to my list of future projects!

You can e-mail Bachiochi at jeff.bachiochi@imaginethatnow.com or post your comment here.

 

The Adafruit Learning System Releases Bluetooth HID Keyboard Controller

Bluefruit2Adafruit’s Bluefruit EZ-Key enables you to create a wireless Bluetooth keyboard controller in an hour. The module acts as a Bluetooth keyboard and is compatible with any Bluetooth-capable device (e.g., Mac, Windows, Linux, iOS, and Android).

You simply power the Bluefruit EZ-Key with 3 to 16 VDC and pair it to a computer, tablet, or smartphone. You can then connect buttons from the 12 input pins. When a button is pressed, it sends a keypress to the computer. The module has been preprogrammed to send the four arrow keys, return, space, “w,” “a,” “s,” “d,” “1,” and “2” by default. Advanced users can use a Future Technology Devices International (FTDI) chip or other serial console cable to reprogram the module’s keys for a human interface device (HID) key report.

BluefruitEach Bluefruit EZ-Key has a unique identifier. More than one module can be paired to a single device. The FCC- and CE-certified, RoHS-compliant modules integrate easily into your project.

Pricing for the Bluefruit EZ-Key begins at $19.95. For more information, visit The Adafruit Learning System. Bluefruit EZ-Key tutorials are also available.

Free Webinar: Bridge Android & Your Electronics Projects

Do you want to add a powerful wireless Android device to your own projects? Now you can, and doing so is easier than you think.

With their high-resolution touchscreens, ample computing power, WLAN support, and telephone functions, Android smartphones and tablets are ideal for use as control centers in your projects. But until now, it has been difficult to connect them to external circuitry. Elektor’s AndroPod interface board, which adds a serial TTL port and an RS-485 port to the picture, changes this situation.

The Elektor AndroPod module

In a free webinar on June 21, 2012, Bernhard Wörndl-Aichriedler (codesigner of the AndroPod Interface) will explain how easy it is to connect your own circuitry to an Android smartphone using the AndroPod interface. Click here to register.

Elektor Academy and element14 have teamed up to bring you a series of exclusive webinars covering blockbuster projects from recent editions of Elektor magazine. Participation in these webinars is completely free!

Webinar: AndroPod – Bridging Android and Your Electronics Projects
Date: Thursday June 21, 2012
Time: 16:00 CET
Presenter: Bernhard Wörndl-Aichriedler (Codesigner of the Andropod Interface)
Language: English

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