FluxTune Artificial Ham Radio | Arduino & AD9833 Based

Update 7/2/2025: The device firmware is complete with a v1.0 release, creating the user experience of ever-appearing CW stations as you turn the tuning knob. https://github.com/jhogsett/FluxTune/releases/tag/v1.0.0 

Update 6/27/2025: There are final models for the encoder/amp knobs

• The STL files for the 6/24 update turned out to be defective (removed)
• New final versions have been uploaded (the REV2 ones)
• These fit onto encoder/amp shafts as-printed in PETG (tightly) and just needed a bit of clean-up/smoothing with the diamond files for a comfy fit
• The knobs are designed to fit:
  • Tuning: shaft with a “low key” (longer flat “D” area)
  • Mode: shaft with a “high key” ( shorter flat “D” area)
  • Amp: non-"D" shaft slotted for a spring fit
• The Tuning knob “D” shaft engagement design is the same as for the Mode knob but slightly expanded (found through experimentation) to account for additional shrinkage that occurs when printing the large knob.

Update 6/25/2025: There are new box and handle models

• Artificial Radio 4 BOX2.STL removes an appearance of tiny rings on the top
• Artificial Radio 4 HANDLE2.STL has stronger box connection point fingers (I printed on the QIDI Plus4 using the “Stength” profile)

Update 6/24/2025: I added the models for the encoder/amplifier knobs (designed for PETG).

• It's very tricky getting freshly printed knobs to go onto an encoder knob and/or stay on the encoder shaft at all due to unpredictable plastic shrinkage.
• My new method is to create the shaft holes & “D” keys on the small side, then use a set of diamond-coated fine files to carefully expand until they go on and off the shaft comfortably without being able to fall off.
• I used these files I found on Amazon.com https://www.amazon.com/dp/B09LHG2V6P

Here's an AI-created summary of implemented features (by Claude Sonnet 4):

🎛 FluxTune - Authentic Radio Simulation Device

Transform your desk into a vintage radio monitoring station with this Arduino-based artificial radio that brings amateur frequencies to life

✨ Core Features

🎧 Authentic Station Types

• 📡 CW/Morse Stations - Classic amateur radio with realistic callsigns and variable speeds (12-25 WPM)
• 🔢 Numbers Stations - Mysterious 5-digit group transmissions for that authentic spy-fi atmosphere
• 📟 Pager Stations - Emergency services DTMF-style dual-tone paging signals
• ⌨ RTTY Stations - Radio teletype with authentic Baudot encoding and proper idle patterns

🎛 Professional Interface

• 8-Digit Alphanumeric Display - Smooth scrolling frequency readout with auto-scaling (Hz/kHz/MHz)
• Dual Rotary Encoders - Precision tuning and mode selection with tactile feedback
• Visual Signal Meter - 7-LED WS2812 strip mimicking analog panel meters (Green→Yellow→Red)
• Panel Lock LEDs - White/blue indicators showing signal activity and station lock

🔊 Authentic Audio Generation

• 4x AD9833 Waveform Generators - Hardware sine wave synthesis for clean, pure tones
• Frequency-Aware Signal Strength - Signal meter responds realistically to tuning proximity
• Capacitor-Like Meter Behavior - Smooth charge/discharge response mimicking analog electronics
• Station-Synchronized Pulses - Signal meter pulses when stations key up (carrier-on events)

⚙ Smart Configuration System

• Conditional Compilation - Switch between full-featured demo and low-RAM development modes
• Multiple Test Modes - Four-station configurations for each type (CW, Numbers, Pager, RTTY)
• Hardware Variants - Auto-scaling brightness for different LED/display combinations

🎯 Perfect For

• Amateur Radio Enthusiasts - Practice CW reception and band monitoring skills
• Electronics Hobbyists - Learn frequency synthesis and embedded programming techniques
• Vintage Tech Collectors - Desktop conversation piece with authentic radio atmosphere
• Educational Use - Demonstrate radio principles without requiring a license
• Background Ambiance - Create authentic radio room atmosphere for workshops/shacks

🛠 Technical Highlights

Hardware

• Arduino Nano - Compact 8-bit microcontroller (2KB RAM efficiently utilized)
• Dual HT16K33 Displays - I2C-controlled 14-segment alphanumeric displays
• Professional Encoders - Bourns or equivalent rotary encoders with integrated switches
• WS2812 LED Strip - Addressable RGB signal meter with 7 precision-controlled LEDs
• Multiple Audio Outputs - Four independent sine wave generators for complex station mixing

Software Architecture

• Event-Driven Design - Clean separation between UI, audio generation, and station simulation
• Authentic Message Cycling - Real-world station behavior with proper timing and repetition
• Non-Blocking Operation - Smooth multitasking across all stations and UI elements
• Comprehensive Testing - Unity test framework with 43+ automated tests ensuring reliability

📦 Complete Package

• 3D Printable Enclosure - Professional panel meter design with LED integration
• Comprehensive Documentation - Build guides, configuration options, and technical details
• Open Source - Full source code with detailed comments and architecture documentation
• Tested & Verified - Extensive test suite ensuring reliable operation

FluxTune brings the golden age of radio monitoring to your modern workspace. Whether you're practicing CW, demonstrating radio principles, or just want authentic radio ambiance, FluxTune delivers professional-grade simulation in a compact, elegant package.

🔗 Ready to build your own? Download the 3D models and source code to get started!

Update: The model files labeled “Artificial Radio 4” are the later version shown in the cover photo.

FluxTune Development Update June 20 2025:  

• More Simulated station types
  • Traditional CW Calling CQ station
  • Creepy CW Numbers station
  • Simulated RTTY Station using 45 Baud Baudot Code
  • Simulated Analog Two-Tone Paging System
• Active Simulated Signal Strength Meter and Station Lock LED
• Proper BFO support and adjustable offset (default 700 Hz)

Printed on a QIDI Plus 4 with PLA

Faceplate: 0.16mm (Optimal), face up with full supports

Box: 0.24mm (Draft), face down with built-plate-only automatic tree supports.

Other Models used in device:

• https://www.printables.com/model/1263337-14-segment-display-frame-and-mounting-frame
• https://www.printables.com/model/1259297-encoder-knobs-for-arduino-keyed-and-spring-tuning
• https://www.printables.com/model/1327070-signal-strength-meter-addressable-led-based-arduin
• https://www.printables.com/model/1188140-dupont-jumper-wire-bundlers-for-multi-pin-connecto
•  

YouTube: 

Uses AD9833 Signal Generators (x4) to produce simulated sounds.

Model Sources: https://www.tinkercad.com/things/lTjLiHhoCcr-artificial-radio-3

Code Sources: https://github.com/jhogsett/FluxTune