Repeater Controller
The BATC ATV Repeater Controller uses a Raspberry Pi 4 as a fully-featured, but simple-to-implement, ATV repeater controller. The design is intended to be used with an HDMI Video switch, but can also be used with older composite video designs.
Every repeater is different and this is designed as a core logic that can be used as the basis for an ATV repeater. The design is flexible with a large number of parameters in a text editable config file so that users can configure it to meet their own needs.
Initial design and construction information will be published here to enable collaborative development, but will be subject to change as the project develops.
The outline requirement specification is here media:BATC ATV repeater controller.pdf
Typical operation
The BATC repeater controller will control either a single or multiple video switchers either by InfraRed or GPIO pins and will generate a carousel of scenes.
Carousel
The carousel can be configured to show up to 99 scenes which can be .jpg or .png images, an input on the video switcher for example mast cam, or a video file. The still images are read each time before display so can be regularly updated by an external source.
Valid signal input
On receipt of a valid signal from, for example, a Ryde receiver, the controller will, key the transmitter, play an image for .5 seconds indicating which input has been activated and then switch to that input. When the receiver closes, the logic will play a "K" image and optional "K" in Morse and go back to the carousel.
The receiver input switching line can be directly from a Ryde receiver or an external source such as a sync detector on an analogue source. Note do NOT exceed 3.3 volts on the GPIO input.
Ident signal
A video and/or audio ident can be generated at an interval set in the config file.
DTMF control
An on-board DTMF generator will allow input selection by remote control and also enable GPIO pins to be toggled to enable the control of external equipment.
Power saving
To enable power saving by turning the repeater transmitter off during quiet periods, a number of options are available such as only key the transmitter when in repeat mode, do not key the transmit during the night time and only enable the beacon for the first 30 minutes of every hour.
Hardware control
The controller will interface to the following:
- Video switches via IR transmitters (note up to 2 IR transmitters can be configured separately allowing multiple video switches to be cascaded).
- Video switchers via hardware lines driven from the RPi GPIO lines (note 3.3v logic output)
- I2C devices such as the McGuffin series Audio and video switches and relay boards.
The IR and I2C commands for each input are set in the config file.
Configuring IR Switching
The IR codes for the HDMI switches used on your repeater will need to entered in the configuration file.
Full details are here: Configuring IR for HDMI Switching
Customisation
While this software is designed to work "out of the box" it will need to be configured for each individual repeater.
Some configuration can be done using the SSH menu - for more details see the Repeater Controller configuration page. Some real-time control is possible using the ssh Console Menu.
The configuration file is too comprehensive for all the functions to be edited from a simple menu and more advanced customisation will require the careful editing of the text file /home/pi/atv-rptr/config/repeater_config.txt;
GPIO Connections
The repeater controller will switch a GPIO output to indicate one of up to eight receiver inputs has been activated.
This can be used to control an external video switcher but note care MUST be taken to buffer the 3.3 volt logic levels used on the Raspberry Pi GPIO pins.
An initial list of GPIO connections is here: Repeater GPIO Connections.
Switching Logic
A detailed description of the operation of the switching logic can be found here: Repeater Switching Logic.
Project status
The target release date is the end of March 2022.
Jan 22 - Aplha release for testing
Feb 10th 2022 An early Beta version of the software (not yet ready for use, but good enough for shack-based testing) can be found here: https://github.com/BritishAmateurTelevisionClub/atv-rptr