by Digital Logic R&D

Android Power Bridge (APB) is an inventive device, developed on the demand of our customers who use uFR Series readers with Android devices.

It finally makes it possible to have an Android device charged while using our uFR readers at the same time, on the very same USB port.

Most Android devices provide power supply through a single micro USB port. This drawback excludes an option to have any accessory device connected at USB port permanently, simply because Android device must be charged occasionally (“from time to time”), when the battery is empty.

If the user needs the constant use of an Android device, occasional charging (“from time to time”) in reality becomes “system downtime”, because the accessory device can not be used while the battery is charging.

The latest models of Android devices also use OTG (“On-The-Go”) USB mode, which is very convenient: Android can act both as a Master or a Slave device, depending on the info it receives from USB port. Still, OTG does not enable Android device to be charged while using the accessory device.

For all the reasons mentioned above Digital Logic launched Android Power Bridge (APB) project. After substantial research and development, we made a sort of the breakthrough in this field, developing a unique APB device.

What is possible with our APB?

User can connect Android device, uFR Series reader and battery charger thru APB, all at once:

  • Android device will get power for constant charging.
  • uFR Series reader will be powered.
  • Both Android and uFR Series reader will communicate to each other.

If the charger is unplugged from APB, uFR Series reader will remain powered by Android device.

If the charger is plugged to APB again, Android device will be powered again too, preserving communication with uFR Series reader.

Whom is it made for?

Anyone who develops on the Android platform and uses our uFR Series reader devices. APB is long expected turnkey solution for continuous operation of affordable Android hardware.

What is so good about APB and what makes it different?

  • Implementation is very easy. We provide our DLReader class in Java for communication with uFR Series reader device, exposing an interface to higher level of application for direct API calls.

  • We provide software examples with source code, for quick start of the development.

  • In 99,9% of the cases, if you used uFR Series reader earlier with Android device, you will only need to implement new DLReader class into your existing project, keeping your code intact.

  • Long time support, provided through our regular and free updates.

  • APB is firmware upgradeable device. Improvements and bug-fixes are available through firmware upgrade and regular updates, free of charge.

There are already some devices with similar purpose, what is new and different?

Yes, there are already devices with a similar purpose on the market. Those devices use some tricks applied on specific Android hardware and not all Android hardware is compatible with them. Basically, those devices are “tricking” OTG port operation on “Sense” pin, this approach is potentially dangerous and could harm the device.

APB uses a significantly different approach.

How it works?

In short, it has lots of stuff going on at the small piece of PCB, supported with sophisticated software written for specialized USB MCU.

Basically, APB has two modes:

  1. When power is present to APB, it acts as a mediator between Android device and uFR Series device, providing both of them with power and establishing a communication link at the same time by using AoA (Android Open Accessory) protocol ( https://source.android.com/devices/accessories/protocol.html ).

  2. If power is not present APB will automatically switch to OTG mode and power the uFR Series reader from Android device, without any need for swapping cables or similar operations.

Digital Logic APB is a professionally engineered device, made by following all engineering standards and rules of good practice, without using dangerous tricks or additional hardware from the market.

All above facts sound like “magic”, are there some hidden weakness, faults or limitations?

There is no magic, well engineered hardware always knows its limits.

Limitations are:

  • At this stage of development, APB can be used only with our uFR Series reader devices.

  • Charging is slower and is defined by USB 2.0 standards, which means that maximum charging current can’t be higher than 500 mA. Compared to standard chargers, it can be 3 to 4 times slower.

  • Slower charging also defines that the power consumption of Android device must not be higher than charging power provided. It means that power hungry rated options like 3G/4G and high brightness of the screen must be used with care.

  • Communication with uFR Series reader devices is established ONLY by using our dedicated Java class – “DLReader” class.

  • There is a time lag in a transition state from OTG to AoA mode and vice verse. It particularly depends on Android device and USB chipset used. This time may vary from 1 to 10 seconds until the communication is established again. However, using DLReader class makes these transitions transparent to end user.

APB device models with various types of connectors

APB comes in several different models/variations, depending on the connection types it supports.

These connection types include: Micro USB, USB, RS232 and RS485.

Please see the table bellow for more information.

Notice: If the connection type you require is not displayed in the table, there is a possibility of developing a customized APB according to your requirements. Please contact us for more information.

DEVICE IMAGEAndroid Power Bridge -4Android Power Bridge -3Android Power Bridge -2Android Power Bridge
DEVICE NAMEAPB – USB 2 USBAPB – AOA DL Serial RS485APB – USB 2 USB DockAPB – AOA DL Serial Dock
CONNECTION TYPE
(ANDROID DEVICE)
Micro USB cableUSB A FemaleMicro USB connectorMicro USB cable
CONNECTION TYPE
(NFC DEVICE)
USB A femaleRJ45Micro USBRS232
CONNECTION TYPE
(DC CHARGER)
Micro USBUSB B FemaleMicro USB connectorUSB A female