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(Skip ahead if you know about SAR.)

FCC and CELEC regulate allowed levels of SAR (Specific Absorption Rate) values of radiation emitted by a mobile device. Common approach is to reduce power used by modem in certain use cases so that less radiation is emitted through device's antennas.

Specific approach

The immediate goal of this project is to have an open source implementation ready for Open Devices program with M-MR1 and N-MR1 versions of AOSP software running on selected devices. The initial implementation focuses on an application which transmits a message to a power module about the current status of device in order to initiate change in power.

Future goals

Since AOSP runs on multiple platforms, the end goal of this project is to run on any Android version and physical platform used by Sony Mobile Communications Open Devices program and AOSP.



In order to build specific APK for your need you can run

make <module_name>

but also you can put the particular module name under PRODUCT_PACKAGES in your device's make file if you want it automatically installed on your device when you flash device images.

* TransPowerBase

Basic power transmission based on battery, WiFi and telephony.

* TransPowerAcc

Together with power transmission based on TransPowerBase module it also sends state of accelerometer to the modem.

* TransPowerProx

Together with power transmission based on TransPowerBase module it also sends state of proximity sensor to the modem.

* TransPowerSensors

Together with power transmission based on TransPowerBase module it also sends states of accelerometer and proximity sensors to the modem as well as stops listening to accelerometer changes if proximity is detected.


Apps described above depend on the following libraries:

* common

Contains definitions of all the common functions of the app taking care of the app's life cycle as well as shared functionalities such as monitoring battery, wifi and telephony.

* common-sensor

Contains definitions of common functions of sensor observers.

* libacc

Implements accelerometer functionality.

* libpower

Implements communication protocol using OEMHOOK API, by which modem is informed about environment states, such as network or sensors, so that it can make a decision on whether to reduce the power or not.

* libprox

Implements observation of proximity sensor.

app versioning

Beginning with versions 1.1.0 and 2.1.0, apps will follow semantic versioning scheme.

  • Version name x.y.z describes the following: x = major build, y = minor build and z = patch.
  • Version code is an integer created out of x.y.z by:
    • ((n & xF0000000) >> 28) + 1 = x
    • (n & x0FFF0000) >> 16 = y
    • n & x0000FFFF = z


The project is licensed under the license stated in the LICENSE file of this project.


The original feature was implemented by the Sony Mobile Communications telephony team. All the contributors are duly noted in the AUTHORS file of this project.


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