Hardrock-50 Remote Display

The Hardrock-50 is a 50W power amplifier for amateur radio QRP transceivers. It has a display showing valuable information like the selected band, the SWR, power, temperature etc. Since I am using the HR50 in a remote station, I cannot directly access those information via the display.

However, the HR50 offers serial communication via a USB port. This project tries to solve this problem with the help of a separate, wifi enabled hardware display. It consists of the following two components:

• Heltec ESP32 board with display
• a python flask application, which represents the communication via the serial interface in the form of an API

This diagram shows which components are required and how the communicate:

This is how the display looks like in action:

You can find a short video here: [https://www.youtube.com/watch?v=50ZxkoQPq7Y]

Client

Preconditions

Hardware

• Heltec ESP32 Wifi Dev Kit Board with OLED

Software

• Arduino IDE

Libraries

• Heltec Libraries: [https://github.com/Heltec-Aaron-Lee/WiFi_Kit_series]
• ArduinoJson
• HTTPClient
• WiFi
• EasyButton

Configuration

Rename the file config.h_dist to config.h and edit the following lines:

const char* ssid = "<ENTER_HERE_YOUR_WIFI_SSID>";
const char* password = "<PASSWORD>";
String api_base_url = "http://<ENTER_HERE_THE_IP_OF_YOUR API_SERVER>:5000";

Example: If your wifi is named "hamradio", your wifi password is "hamradio4life" and the IP address of your server is "192.168.1.100", your config should look like this:

const char* ssid = "hamradio";
const char* password = "hamradio4life";
String api_base_url = "http://192.168.1.100:5000";

Installation

Add the files to your Arduino IDE, install all necessary libraries, configure the board and USB/serial port, compile the sketch and then upload it.

Usage

Execute the server (see below) and power up the ESP board. The following user interaction is possible:

• short press of the upper button: executes a shell script / system command / program (Server config parameter 'shell_cmd')
• long press of the upper button: sends a serial commannd to the HR50. The default command will initiate the tuning cycle during the next transmission (Server config parameter 'serial_cmd')
• the lower button reboots the device

Error handling

• If wifi is unavailable or misconfigured, the device will show "No Wifi!" on the screen
• HTTP Errors will also displayed on the OLED
• When you key up your TRX and therefore the HR50, no serial communication is possible. The latest gathered information will still be displayed on the screen but there will be a "(!)" in the third row as an indicator for this situation.

Server

Preconditions

You need a computer connected to the Hardrock-50 via USB, e.g. a Raspberry Pi. This system needs to be able to run Python and has to be connected to your network.

Configuration

Open the file hr50_rd_server.py and adapt the following lines to your environment regarding the USB connection to the HR50:

serial_port = '/dev/ttyUSB0'
baud = 19200

Edit the following lines if you want to customize the actions performed when pressing the upper button:

shell_cmd = "./scripts/toggle_antenna.sh"
serial_cmd = "hrtu1"
serial_cmd_msg = "Tune"

serial_cmd_msg is a message that will be displayed on the screen after executing the serial_cmd.

Execution

Executing this script will spawn a web server running on port 5000. This is not meant for production use and/or public exposure. Anyone able to access this server via the network can alter any settings on your HR50.

Run it as follows:

# cd server
# ./bootstrap.sh

API Endpoints

There are two API endpoints available:

/exec_serial

This method allows you to send commands to the HR50. The commands can be taken from the HR50 operator's manual and do not require the trailing ";"

/exec_shell

This method allows you to execute shell commands on the server

/get_status

This method returns all avalable information in JSON