# MegaDongle
This is an RF interface designed primarily for use as a ground station
interacting with Altus Metrum altimeters on board high power model
rockets. Think of it as a USB to RF interface. The RF filter components
are set for use in the vicinity of 435 Mhz.
MegaDongle is intended to supplement and perhaps eventually replace
[TeleDongle](../TeleDongle) with a product that provides on the order of
6dB better transmit and receive RF performance, at a modest increase in
manufacturing cost.
For the latest MegaDongle firmware and related software, please
visit the [AltOS](../AltOS) page on this site.
These are photos of the current MegaDongle prototypes:
## Features ##
### User View ###
* 70cm ham-band transceiver for interaction with Altus Metrum flight computers
like [TeleMetrum](../TeleMetrum/)
* programmed for 38k4 GFSK data rate with forward error correction
* USB interface for power, configuration, and data interface
* 4 pin Tyco MicroMaTch connector for debug and flash programming
* 8 pin Tyco MicroMaTch connector supports serial or SPI interface
* 1.1 x 1.1 inch 4-layer board, fits inexpensive Hammond 1551 plastic enclosure
### Developer View ###
* Hardware Features
* ST Micros [STM32L151](http://www.st.com/internet/mcu/product/248821.jsp) ARM Cortex M3 based Microcontroller
* TI [CC1125](http://www.ti.com/product/cc1125) Ultra-High Performance RF Narrowband Transceiver
* 150mA 3.3V LDO regulator
* takes input from USB interface by default
* output appears on 8-pin companion connector
* can take input from 8-pin companion connector in non-USB applications
* Software Features
* Written mostly in C with some ARM assembler
* Runs from on-chip flash, uses on-chip RAM
* USB serial emulation for data interface
* Tools Used
* [gEDA](http://www.gpleda.org/) for schematic capture and PCB layout
* Licenses
* The hardware is licensed under the [TAPR](http://www.tapr.org) [Open Hardware License](http://www.tapr.org/ohl.html)
* The software is licensed [GPL version 2](http://www.gnu.org/licenses/old-licenses/gpl-2.0.html)
## [Production History](../production) ##
## Artifacts ##
There is a single manual for most Altus Metrum products including MegaDongle,
which is available in [html](../AltOS/doc/altusmetrum.html) and
[pdf](../AltOS/doc/altusmetrum.pdf) formats.
The hardware design current gEDA files are available from
[git.gag.com](http://git.gag.com) in the project
[hw/megadongle](http://git.gag.com/?p=hw/megadongle;a=summary).
The firmware can be found on the [AltOS](../AltOS) page on this site.
## Future Plans ##
Our version 0.1 design was abandoned after we discovered the need for more
processing power to implement in software the same FEC approach provided
by the CC1111 we used in [TeleDongle](../TeleDongle).
Three units of version 0.2 prototypes were assembled and worked just
fine, but it was unclear that the performance was actually better than
TeleDongle with our modulation and coding scheme. We may or may not work
on this design more in the future.
## Features ##
### User View ###
* 70cm ham-band transceiver for interaction with Altus Metrum flight computers
like [TeleMetrum](../TeleMetrum/)
* programmed for 38k4 GFSK data rate with forward error correction
* USB interface for power, configuration, and data interface
* 4 pin Tyco MicroMaTch connector for debug and flash programming
* 8 pin Tyco MicroMaTch connector supports serial or SPI interface
* 1.1 x 1.1 inch 4-layer board, fits inexpensive Hammond 1551 plastic enclosure
### Developer View ###
* Hardware Features
* ST Micros [STM32L151](http://www.st.com/internet/mcu/product/248821.jsp) ARM Cortex M3 based Microcontroller
* TI [CC1125](http://www.ti.com/product/cc1125) Ultra-High Performance RF Narrowband Transceiver
* 150mA 3.3V LDO regulator
* takes input from USB interface by default
* output appears on 8-pin companion connector
* can take input from 8-pin companion connector in non-USB applications
* Software Features
* Written mostly in C with some ARM assembler
* Runs from on-chip flash, uses on-chip RAM
* USB serial emulation for data interface
* Tools Used
* [gEDA](http://www.gpleda.org/) for schematic capture and PCB layout
* Licenses
* The hardware is licensed under the [TAPR](http://www.tapr.org) [Open Hardware License](http://www.tapr.org/ohl.html)
* The software is licensed [GPL version 2](http://www.gnu.org/licenses/old-licenses/gpl-2.0.html)
## [Production History](../production) ##
## Artifacts ##
There is a single manual for most Altus Metrum products including MegaDongle,
which is available in [html](../AltOS/doc/altusmetrum.html) and
[pdf](../AltOS/doc/altusmetrum.pdf) formats.
The hardware design current gEDA files are available from
[git.gag.com](http://git.gag.com) in the project
[hw/megadongle](http://git.gag.com/?p=hw/megadongle;a=summary).
The firmware can be found on the [AltOS](../AltOS) page on this site.
## Future Plans ##
Our version 0.1 design was abandoned after we discovered the need for more
processing power to implement in software the same FEC approach provided
by the CC1111 we used in [TeleDongle](../TeleDongle).
Three units of version 0.2 prototypes were assembled and worked just
fine, but it was unclear that the performance was actually better than
TeleDongle with our modulation and coding scheme. We may or may not work
on this design more in the future.