ePaper Prototype with Yaesu FT-818

See Notes for device, build, and resource information

The first phase Proof of Concept repo on GitHub

Requirements

• Python 3
• Hamlib Python bindings for CAT/radio-control scripts

Fonts

You will need to obtain the Audiowide-Regular.ttf font from Google and place it in the fonts subdirectory.

Install Hamlib on Debian/Raspberry Pi OS:

sudo apt install python3-hamlib

If your platform does not provide python3-hamlib, use pip:

pip install hamlib

Running the PoC

python3 radio_app.py

Screen function demos

python3 display_demo.py

FT-818 CAT demo

NOTE: the configuration file ft818_cat_demo_config.json is set up for a radio connected to /dev/ttyUSB0 with a baud rate of 9600. You may need to adjust these settings for your radio and connection. If you are using the LDG Z-817 tuner, you will need to adjust the configuration file baud rate to 4800.

python3 ft818_radio_app.py

FT-818 button app

This app uses Hamlib to control FT-818 features from the 4 HAT buttons.

• Button 1: force full display refresh
• Button 2: band up
• Button 3: cycle tuning step
• Button 4: shutdown (same as pressing all 4 buttons)
• Button 1+2: band up
• Button 3+4: band down
• Button 1+3: frequency increment (by current tuning step)
• Button 2+4: frequency decrement (by current tuning step)
• All 4 buttons: shutdown

Display protection policy:

• full-screen refresh no faster than every 3.0 seconds
• partial refresh no faster than every 0.5 seconds
• automatic full-screen refresh after 5 seconds of inactivity when 2 or more partial refreshes have occurred

Run it with:

python3 ft818_radio_app.py

System diagram

ft818_radio_app.py is the current runtime entry point for the FT-818 app. It loads configuration, opens the Hamlib rig, constructs the display and radio state objects, and then runs the main loop that ties input handling, CAT polling, and ePaper refreshes together. In the current prototype, GPIO buttons are the active input source, but they should be treated as one replaceable input module rather than a permanent architectural requirement.

flowchart LR
	config["ft818_config.json\nradio / polling / ft818_app settings"]
	hamlib["Hamlib Rig\nexternal CAT control"]

	subgraph app["ft818_radio_app.py"]
		main["main()"]
		controller["FT818RigController\nHamlib write + refresh wrapper"]
	end

	subgraph poller["ft818_poller.py"]
		pollerFns["load_config()\nbuild_rig()\npoll_radio()\nfreq_to_band()"]
	end

	subgraph state["radio.py"]
		radio["Radio\nobservable UI state model"]
	end

	subgraph input["button_state_manager.py"]
		buttons["ButtonStateManager\nGPIO button reader"]
	end

	subgraph futureInput["future input options"]
		touch["touchscreen UI"]
		encoder["rotary encoder"]
		remote["remote / network control"]
		auto["status-only / automation"]
	end

	subgraph commands["radio_command_handler.py"]
		buttonState["ButtonState"]
		handler["RadioCommandHandler\ncurrent command dispatcher"]
	end

	subgraph displayFile["radio_display.py"]
		display["RadioDisplay\nrender + refresh policy"]
	end

	subgraph epdFile["lib/epd2in7_V2.py"]
		epd["EPD\nWaveshare display driver"]
	end

	main -->|loads| config
	main -->|uses| pollerFns
	pollerFns -->|creates and polls| hamlib
	main -->|creates| controller
	main -->|creates| radio
	main -->|creates| display
	main -->|creates| handler
	main -->|creates| buttons
	main -->|instantiates| epd

	controller -->|wraps| hamlib
	controller -->|reuses poll helpers| pollerFns
	controller -->|updates snapshot| radio
	buttons -->|current implementation returns| buttonState
	buttonState -->|translated into commands by| handler
	touch -->|future commands| handler
	encoder -->|future commands| handler
	remote -->|future commands| handler
	auto -->|future commands or no commands| handler
	handler -->|dispatches actions to| controller
	handler -->|can request refresh/shutdown via| display
	handler -->|fallback state updates| radio
	radio -->|observer notifications| display
	display -->|draws through| epd

Loading

At runtime, the current main loop reads GPIO button states through ButtonStateManager, routes them through RadioCommandHandler, applies CAT commands through FT818RigController, refreshes the shared Radio snapshot from Hamlib poll data, and lets RadioDisplay redraw the ePaper panel when the observable state changes.

The important architectural boundary is between input generation and command execution. Buttons are just one way to generate commands. A future hardware revision could replace them with a touchscreen, a rotary encoder, remote control, or even a display-only status mode while still keeping the same radio-state, polling, and display layers.