bytran -|- spectral calculations for portable devices using the HITRAN database


Planned for bytran 1.5

We hope to complete Version 1.5 update of bytran by the end of this summer (of 2020).   A message will be posted here in late July - August if there are any delays.

The features planned for bytran 1.5 update include (1) the implementation of the Hartmann-Tran and a couple of other optional lineshape profiles, (2) as well as some slight improvements to the desktop versions.

(3) The Texas Istrumnents has just issued a new Wireless MCU Launchpad development kit and a new version of SensorTag LPSTK-CC1352R which is significantly different from its predecessor SensorTag CC2650STK (alternative link) bytran currently supports.   The support of the new SensorTag is planned for bytran version 1.5.   The new SensorTag LPSTK-CC1352R lacks an on-board pressure sensor but it can be added by interfacing with a pressure sensor development board (see examples at Mouser and Adafruit) or else with a to be discontinued booster pack BOOSTXL-SENSORS plugin module which also includes other sensors.   As an alternative to the SensorTag the BOOSTXL-SENSORS may also be used with the new Wireless MCU Launchpad development kit.

The new SensorTag is "a merge" of the SensorTag in its traditional sense with the TI's LaunchPad Microcontroller Development Board.   As such the new SensorTag LPSTK-CC1352R and the Wireless MCU Launchpad provide more options to be customized, to add new hardware, and to interface with.

Mobile versions

Android™ 4.4 and above, iOS 8 and above, or Windows 10 (ARM & x64).
The iOS version will be updated with the relase of bytran 1.5.  The Windows Phone version does not offer Image and Data sharing.

Desktop versions

Desktop versions currently do not include and installer and contain unmodified mobile interface. Additional information about previous releases is available in the   Archive
  (1) Linux versions are currently unavailable due to the issues linking SSL libraries to access HITRAN over secure socket layers.   This issue will most likely be addressed with the release of bytran 1.5.   (2) The serial port profile Bluetooth connectivity used for remote control may not work (or requires additional setup) under Ubuntu and Mac OS.

Raspberry Pi board

Startng with version 1.3 bytran supports the Sense HAT add-on board.   To run bytran under Raspbian (tested on Stretch with Raspberry Pi 3) a script file supplied should be used as outlined in the readme file within the archive.

Source code

Distributed under the MIT license.   Cross-platform source code, written in Qt/C++.   Mobile and desktop operating systems supported.

Latest Version 1.4

Read this note to compile the source code for Raspberry Pi.


Distributed under the MIT license

bytran source code and binary are provided under the terms of the MIT license. The bytran distribution also includes dynamically linked Qt libraries it relies on which are distributed under the LGPL (Version 3) license, more information is available here.

Original bytran operation video

Example usage of the original bytran version 1.0 Alpha on a cell phone
(May 12, 2016)

About bytran

bytran is an application for calculating atmospheric and molecular absorption spectra using the HITRAN database and the line-by-line method.   The concentrations of molecules, optical pathlength, total pressure, temperature, and other input parameters are used to model the gas mixture optical transmission spectra as a function of wavelength.

Among other features bytran can be controlled remotely and supports optional usage of SensorTag, Sense Hat, and cell phone sensors for calculations using empirical readings of ambient total pressure, temperature and humidity (H2O vapor concentration) .   For more information read the overview of bytran, the bytran publication and the change log of the bytran releases.

Radiance now viewable as "separate molecules"
Coordinate rulers added (activated on zoom)

The usage of cell phone sensors is currenly limited to the Android operating system due to the limitations of the Qt environment.

New features in bytran 1.4

Kielkopf algorithm approximation of the Voigt profile for fast low accuracy estimates -|- HITRAN database storage options -|- Wavenumber resolution settings

Kielkopf algorithm for the Voigt profile

Kielkopf low accuracy algorithm for the calculation of the Voigt profile was added to bytran which may be useful for fast calculations where high accuracy is not required.


HITRAN database storage settings

The HITRAN database may now be stored and accessed in a binary format as an option.   The binary mode was introduced to speed up the HITRAN database read times.   The HITRAN database settings window allows selecting the HITRAN database storage mode (ASCII, binary, or both ASCII and binary) as well as to select which files (ASCII or binary) are to be used in calculations.   For phones running Android an option was introduced to be able to store the HITRAN downloaded data, the configuration file and the calculation results on a removable SD card under the Android operating system.


Wavenumber resolution settings

The wavelength resolution may now be specified as:
( 1 )   An absolute value in current wavelength units
( 2 )   As the number of data points along the wavelength span
( 3 )   As a combination of options ( 1 ) and ( 2 ) above where the coarser resolution specified by the two methods is used in calculations.  This third option was introduced to automatically reduce the number of data points for shorter calculation wavelength spans to speed up the calculations for narrower wavelength spans.

Remote control & data retrieval

Remote connection to bytran to run calculations and retrieve data
Bluetooth -|- WebSockets -|- Serial Port

Remote control & data retrieval

Remote control of bytran may be carried out over classic Bluetooth, WiFi / Ethernet (using WebSockets) or the Serial port.   The communication is carried out using the newly introduced bytran communication protocol and enables remote execution, and retrieval of calculation results.   The following links provide information on how to test and use bytran connectivity over Bluetooth, WebSockets, or the Serial Port.

The WebSockets communication may be programmed using HTML5 and JavaScript to operate from within the web-browser.   To simplify processing of the calculated data starting with bytran version 1.3 the calculation results are also available as absorption cross-section (cm2 / molecule).

Thermometer, Barometer & Humidity sensors

Line-by-line calculations using measured meteorological data -|- Sensors may be used to provide empirical values of total pressure, temperature and water vapor concentration as input instead of manual entry -|- SensorTag, Cell phone built in sensors, Sense HAT


NOTE: The new just launched SensorTag model LPSTK-CC1352R and the Wireless MCU Launchpad development kit are not yet supported by bytran, its support is planned for bytran version 1.5.

SensorTag (model CC2650STK) is a keychain size coin battery operated bluetooth device containing temperature (TMP007 and BMP280, ~ ±1 °C accuracy), pressure (BMP280, ~ ±1 hPa accuracy) and humidity (HDC1000, < 3% accuracy) sensors.   Starting with version 1.2 bytran is able to connect to SensorTag and access its sensors.   The SensorTag may be purchased directly from Texas Instruments or its distributors.


Cell phone sensors

Bytran is able to access cell phone built in sensors however this support is limited to the thermometers and barometers under the Android operating system due to the present limitations of the Qt environment.   Future bytran editions will likely include custom code to suppport the iOS operating system and the humidity sensor.   A search of cell phones with a barometer, thermometer and/or humidity sensor may be performed here.


Raspberry Pi's Sense HAT

Starting with version 1.3 bytran supports the Sense HAT add-on board for Raspberry Pi to measure ambient total pressure (LPS25HB, accuracy of 10 to 100 Pa), temperature (HTS221, < 0.5 °C accuracy) and humidity (HTS221, < 3.5% accuracy) for input into the line-by-line calculations instead of the manual entry.

Though not currently supported by bytran, alternatives to the Sense HAT board are emerging which are compatible with the Raspberry PI.   One such board is the Environmental Sensor Board by Coral.

To report a bug or suggest a feature please email us:

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