====== Raspberry Pi with directly connected radio module ======

===== Hardware =====

The RFM69HW and optional BMP085 modules are mounted on a [[http://shop.ciseco.co.uk/slice-of-pi-add-on-for-raspberry-pi/|Slice of Pi]] board. The BMP180 sensor uses the same protocol as the BMP085 and has also been tested.

{{:dbrooke_nodes:p1010894.jpg?direct&200|}}
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==== Connection Summary ====

[[http://pinout.xyz/|Raspberry Pi Pinout]]


^  RFM69HW         ^  Slice of Pi  ^  Notes                                   ^
|  NSS             |  SPI_0        |                                          |
|  MOSI            |  MOSI         |                                          |
|  MISO            |  MISO         |                                          |
|  SCK             |  SCLK         |                                          |
|  GND             |               |Connect to GND at end of XBee connector   |
|  ANT             |               |Connect 1/4 wave wire as antenna          |
|  3.3V            |  3V3          |                                          |
|  DIO4            |  G23          |Wiring Pi 4 / GPIO23                      |
|  DIO0            |  G17          |Wiring Pi 0 / GPIO17                      |
|  RESET           |  G04          |Wiring Pi 7 / GPIO04                      |
^  BMP085/BMP180   |               |                                          |
|  GND             |  GND          |Next to 3V3                               |
|  +5V             |  5V0          |Some breakout boards use a 3.3V  supply   |
|  SDA             |  SDA          |                                          |
|  SCL             |  SCL          |                                          |

===== Software =====

Based on daveake's "Basic working receiver" code which I used as a testbed to develop changes to mitigate the effect of interference and now provides a reliable gateway.

==== Tools and Libraries ====

Install git and the curl and wiringpi libraries: **sudo apt-get install git libcurl4-openssl-dev wiringpi**


==== Repository ====

[[https://github.com/dbrooke/UKHASNetPiGateway]]

==== Building ====

An initial download can be done with:

**%%mkdir ~/ukhasnet ; cd ~/ukhasnet && git clone https://github.com/dbrooke/UKHASNetPiGateway.git%%**

After which the submodules for the libraries can be initialised with:

**%%cd UKHASNetPiGateway && git submodule update --init --recursive%%**

The software should then build without errors by typing:

**%%make%%**

==== Configuration ====

Configuration is read from a file **gateway.ini** which needs to be present in the directory from which the software is started.

A sample file is provided with all parameters commented out and showing the default value where applicable. A minimal configuration requires the node ID to be specified.

By default the software provides gateway functionality without any telemetry from the gateway itself, other than the bootup packet with the location data (if specified in the configuration file).

If the Pi is fitted with a BMP085 (or BMP180) pressure and temperature sensor then data from this can be periodically uploaded. This support can be enabled in the configuration file.

The xAP support is experimental and currently just broadcasts a message with the raw UKHASnet payload. It is likely to be replaced with MQTT.

===== Usage =====

==== System Configuration ====

To make sure that the SPI bus is enabled run **sudo raspi-config** and then select Advanced Options where you should see SPI listed and can enable it. If you have a BMP085/BMP180 sensor fitted then you should also enable the I2C bus.

==== Manual Start ====

Access to the SPI bus requires that the program is run as root, so from the build directory run **sudo ./gateway**

==== Automatic Start ====

My preferred method to invoke the program, so that it is started when the system boots and still allows a console to attach to observe its operation, is to start it in a detached screen session from cron.

Install screen on the Pi by running **sudo apt-get install screen**

The following assumes the use of the default ''pi'' account and that the repository was cloned below ''/home/pi/ukhasnet''

Run **crontab -e** which will open your crontab file in an editor and add the following line at the bottom of the file:

<code>
@reboot /usr/bin/screen -dmUS gateway /usr/bin/sudo /home/pi/ukhasnet/UKHASNetPiGateway/gateway
</code>

=== Remote access from Linux ===

If the name of the system running the gateway is ''ukhasnet-gw'' then the following command on a linux desktop system will attach to the running gateway and display its output in a new window:

**uxterm -title ukhasnet-gw -e ssh ukhasnet-gw -t screen -d -r gateway**

To detach, leaving the gateway running, enter **CTRL-A** followed by **d**