Created for Falcon Player 6.0+ (FPP) as a plugin to generate RDS (radio data system) messages similar to what is seen from typical FM stations. The RDS messages are fully customizable with static text, breaks, and grouping along with the supported file tag data fields of title, artist, album, genre, track number, and track length, as well as main playlist position and item count. Currently, the plugin supports the QN8066 chip and there are plans to add the Si4173 in the future. The chips are controlled via the I2C bus.
Important
There are other similar looking boards, so double check for the QN8066 chip. For a detailed look at identifying QN8066 boards, check out Spectraman's video.
Aliexpress link to purchase QN8066 FM Transmitter
The QN8066 transmitter board needs an antenna for safe operations.
- Small bench testing option - https://www.amazon.com/gp/product/B07K7DBVX9
- 1/4 wave ground plane antenna calculator - https://m0ukd.com/calculators/quarter-wave-ground-plane-antenna-calculator/
- Show ready option 1/4 wave - https://www.amazon.com/Transmitter-Professional-87-108mhz-0-5w-100w-Waterproof/dp/B09NDPY4JG
- Inexpensive 1/4 wave option - https://www.aliexpress.us/item/2251832695723994.html
- BNC to BNC cable - https://www.amazon.com/gp/product/B0BVVVRYZL/)
(More detail to be added)
Caution
Do not run the PWM wire along side the I2C wires. During testing this caused failures in the I2C commands as soon as PWM was enabled.
- The connection on the transmitter board is a 5-pin JST-XH type connector, 2.54mm.
- The Raspberry Pis use a female Dupont connector and we recommended using a 2 x 6 block connector.
- The BeagleBone Blacks (BBB) use a male Dupont connector (recommendation pending BBB support work in progress).
If you are comfortable with crimping and making connectors, here are examples of what to use
- JST-XH connectors - https://www.amazon.com/dp/B015Y6JOUG
- Dupont connectors - https://www.amazon.com/dp/B0774NMT1S
- Single kit with both JST-XH and Dupont connectors - https://www.amazon.com/dp/B09Q5MPM7H/
- JST-XH kit with Crimping Tool - https://www.amazon.com/gp/product/B094XSF2GK
Pre-crimped wires are also an options
- JST-XH Pre-crimped wires - https://www.amazon.com/dp/B0BW9TJN21
- Dupont Pre-crimped wires - https://www.amazon.com/dp/B07GD1W1VL
The green PWM wire runs next to yellow 3.3V and orange GND wire until right before the end to eliminate issue with interference. Keeping the cable as short as possible helps to reduce interference.
(Support for the BBB is still in progress)
Given the nature of an FM transmitter, interference is potential problem. This interference commonly shows up as I2C errors which become more frequent as transmitter power increases. Moving the antenna away from the RPi/BBB and the transmitter board can reduce this. A significantly more robust setup it to locate the RPi/BBB and transmitter board inside a grounded, metal case such as was done by @chrkov here:
The recommended QN8066 transmitter board can take a PWM signal to increase its power output. Be sure to comply with all applicable laws related to FM broadcasts.
Caution
Do not run the PWM wire along side the I2C wires. During testing this caused failures in the I2C commands as soon as PWM was enabled.
On the Raspberry Pi, in order to use the hardware PWM, the built-in analog audio must be disabled and an external USB sound card or DAC is required. The built-in audio uses both hardware PWM channels to generate the audio, so PWM cannot be used for other purposes when enabled. Software PWM is also an option, but at an increased CPU cost and a decrease in duty cycle accuracy.
From the Dynamic RDS configuration page, under the Power Settings, enable PWM.
This will automatically modify the /boot/config.txt:
- Comment out all
dtparm=audio=onlines with a # - Add the line
dtoverlay=pwm,pin=18,func=2by default Under the Advanced Options at the bottom of the configuration page, the output pin can be selected. This is also where Software PWM can be selected on most other pins.
Tip
Don't forget to change the Audio Output Device in the FPP Settings to use the USB sound card or DAC
The Dynamic RDS plugin has the ability to work in conjunction with the FPP After Hours Music Plugin to provide RDS Data from an internet stream of music. The information from the stream is populated in the Title field.
Once the After Hours Music Plugin is installed, the integration can be enabled on the Dynamic RDS configuration pages in the MPC / After Hours Music section.
It is an option to use scripts to change Dynamic RDS option value. As an example, this could be used to change the PS and/or RT style text to be different during the show verses after. The following is a bash script that can update the style text and have the plugin start using it without restarting FPP.
#!/bin/bash
curl -d 'Merry|Christ-| -mas!|{T}|{A}|[{N} of {C}]' -X POST http://localhost/api/plugin/Dynamic_RDS/settings/DynRDSPSStyle
curl -d 'Merry Christmas! {T}[ by {A}]|[Track {N} of {C}]' -X POST http://localhost/api/plugin/Dynamic_RDS/settings/DynRDSRTStyle
curl http://localhost/api/plugin/Dynamic_RDS/FastUpdate
The single quotes around the style text in the script are important so the Linux shell (bash) won't try to interpret what is in there. This example could be saved as a file in the media/scripts folder and then use it with the scheduler (via Command -> Run Script) or playlists.
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Verify transmitter is working on it's own
- Connect the original screen, connect antenna, and 12v power
- Connected to audio input near the screen connector
- Check for transmission with a radio. If not, transmitter maybe bad and need to be replaced
- Remove power, then disconnect screen
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Verify transmitter is working with RPi/BBB
- With everything powered off, connect the transmitter to the RPi/BBB for 3v3, GND, SDA, and SCL
- Do NOT connect the PWM pin
- Verify each wire is connected correctly 3v3, GND, SDA, and SCL
- Power up the RPi/BBB
- Transmitter will power up from power supplied by RPi/BBB (Do NOT connect 12v power yet)
- Verify the transmitter shows up on the I2C bus at 0x21
- Either from the Dynamic RDS config page OR
- SSH into the RPi
i2cdetect -y 1and run or on BBB runi2cdetect -r -y 2
- If transmitter does not show up
- Double check each wire is connectioned correctly 3v3, GND, SDA, and SCL
- No really, go double check! It can happen to anyone! :)
- Check each wire's continuity to make sure there isn't a break
- Enable Debug logging for the Engine
- Check for read and/or write errors in Dynamic_RDS_Engine.log
- If too many errors happen, then I2C fails and the Engine exits
- Reduce the Amp Power
- Try using Software I2C
- Enclose the RPi/BBB and transmitter in a grounded, metal box with the antenna outside of the box
- Check connection and wire continuity between RPi/BBB
- Disconnect transmitter 12v power if connected and check I2C bus with
i2cdetect -y 1
- If errors happen at random
- Make sure the PWM wire does NOT run along side the I2C wires, interference can occur
- Try to lower the Chip Power and Amp Power, RF interference can impact I2C
- Move the antenna further away from the transmitter board and RPi/BBB
- If too many errors happen, then I2C fails and the Engine exits