Tartan Artibeus Ground Support

This repository provides ground support for the Tartan Artibeus satellite.

Directory Contents

• 00-setup: Setup scripts
• 01-rx: Testbed receiver script
• 02-tx: Testbed transmitter script
• images: Repository images
• README.md: This document

Software Setup

From a Linux terminal (tested on Ubuntu 20.04):

1. Clone the repository:

cd $HOME
mkdir git-repos
cd git-repos/
git clone https://github.com/CMUAbstract/tartan-artibeus-ground-support.git
cd tartan-artibeus-ground-support/

2. Run the setup script:

cd 00-setup/
./setup_p3_venv.sh

Testbed Preparation

1. Connect an antenna with a u.FL connector to Board A. Connect another antenna with a u.FL connector to Board B.

2. Connect one of the FTDI cables to Board A. Connect the ground (black) wire to the "FTDI Cable GND" header. Connect the FTDI TX (orange) wire to the "FTDI Cable Orange" (Board A RX1) header. Connect the FTDI RX (yellow) wire to the "FTDI Cable Yellow" (Board A TX1) header.

3. Connect the other FTDI cable to Board B. Connect the ground (black) wire to the "FTDI Cable GND" header. Connect the FTDI TX (orange) wire to the "FTDI Cable Orange" (Board B RX1) header. Connect the FTDI RX (yellow) wire to the "FTDI Cable Yellow" (Board B TX1) header.

4. Set a variable power supply to output 3.3 V with a maximum current of 200 mA. Ensure that the power supply is NOT outputting power. Connect the power supply ground to the breadboard ground row (marked in black). A black wire is provided. Connect the power supply voltage to the breadboard voltage row (marked in red). A red wire is provided.

5. Connect the breadboard ground row to Board A GND. A black wire is provided. Connect the breadboard ground row to Board B GND. A black wire is provided.

6. Ensure that the power supply is OFF. Connect the breadboard voltage row to Board A 3.3 V. Connect the breadboard voltage row to Board B 3.3 V.

Testbed Usage

Each of the FTDI USB cables must be connected to a computer running a terminal. Both cables may be connected to the same computer, or each cable may be connected to a different computer.

The FTDI cables must be connected to an Earth-grounded computer, e.g. a desktop computer. A laptop computer, even while charging, is insufficient. We recommend plugging the FTDI cables into a well-grounded, desktop computer.

1. Open a new terminal window. This window will be designated the RX Terminal. Before inserting Board A FTDI USB into the desktop computer, execute the following terminal command. Depending on the device configuration, you may receive "No such file or directory" or a list of devices.

ls -al /dev/ttyUSB*

2. Insert Board A FTDI USB into the desktop computer. Repeat the following terminal command. Make note of the new device name, e.g. /dev/ttyUSB0.

ls -al /dev/ttyUSB*

3. Open a new terminal window. This window will be designated the TX Terminal. Before inserting Board B FTDI USB into the desktop computer, execute the following terminal command. Depending on the device configuration, you may receive "No such file or directory" or a list of devices.

ls -al /dev/ttyUSB*

4. Insert Board B FTDI USB into the desktop computer. Repeat the following terminal command. Make note of the new device name, e.g. /dev/ttyUSB1.

ls -al /dev/ttyUSB*

5. Enable the power output on the variable power supply. Both Board A and Board B should exhibit a lit LED.

6. In the RX Terminal, execute the following commands. Substitute the appropriate RX Terminal device name.

cd $HOME/git-repos/tartan-artibeus-ground-support/01-rx/
source ../p3-env/bin/activate
python3 rx_test.py /dev/ttyUSB0

7. In the TX Terminal, execute the following commands. Substitute the appropriate TX Terminal device name.

cd $HOME/git-repos/tartan-artibeus-ground-support/02-tx/
source ../p3-env/bin/activate
python3 tx_test.py /dev/ttyUSB1

The TX Terminal should display a sequence of 12 transmitted commands. Each command is transmitted via RF and received by the other board. The RX Terminal should display a sequence of 12 matching received commands. The receiving board replies to each command as it arrives. Both terminals display the command replies; the RX Terminal displays the reply that is sent via RF, and the TX Terminal displays the received reply.

After the test completes, deactivate the Python virtual environment in each terminal with the following command.

deactivate

Ensure that the power supply is turned OFF.

Manifest

• Testbed, including two mounted radio boards
• A tiny breadboard, two u.FL antenna, and jumper wires
• Two FTDI cables with jumper wires attached
• A primary radio board and a secondary, backup radio board
• Two spare FTDI cables
• Spare antenna (u.FL and SMA)
• A CC-Debugger

Communicating with TA-1

1. To communicate with Artibeus, connect a radio board to power, ground and an FTDI cable connected to a well grounded computer as described above. We recommend closing any terminals open from the testbed test to avoid confusion.

2. Attach the radio board to the ground station antenna output via the u.FL connector.

3. In a terminal, execute the following commands. Substitute the appropriate device nameIn a terminal, execute the following commands. Substitute the appropriate device name.

cd $HOME/git-repos/tartan-artibeus-ground-support/01-rx/
source ../p3-env/bin/activate
python3 ack_test.py /dev/ttyUSB0

The terminal will display the results of 5 attempts to "ack" TA-1. Each command will timeout if it does not receive a reply within 15 seconds.

License

Written by Bradley Denby
Other contributors: Emily Ruppel

See the top-level LICENSE file for the license.