BATC ATV repeater logic software design

Ideas, technical topics, help and discussion for ATV repeater builders
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g8gtz
Posts: 1548
Joined: Wed Apr 07, 2010 6:26 pm

BATC ATV repeater logic software design

Post by g8gtz » Sun Jan 02, 2022 6:20 pm

Prompted by the desire to replace the video switcher and logic on GB3HV, I put together a specification for an HDMI switched and repeater logic which Dave G8GKQ has decided to turn into the standard BATC repeater logic.

Based on the RPi 4 (of course) the software will control a video switcher either by RS232 or GPIO pins and will generate a carousel of images. On receipt of a valid signal from, for example, a Ryde receiver, it will switch to that input - when the receiver closes, the logic will play a key sequence, dekey the tx and go back to the carousel.

We recognise every repeater is different and so we intend this to be a core logic that can be used as the basis for your repeater. We have tried to think of the type of options users will want and Dave has put a lot of parameters in the SSH config file but we won't be doing specials! The code will be on Github so you can modify it to suit your own needs.

The requirement spec (attached) has only just been finalised and Dave has just started writing code - an initial release is targeted to be available at the same time as the next issue of CQ-TV.

73s
Noel - G8GTZ
BATC ATV repeater controller.pdf
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SkyVision
Posts: 15
Joined: Fri Jan 24, 2020 1:51 pm

Re: BATC ATV repeater logic software design

Post by SkyVision » Wed Jan 05, 2022 4:19 am

Hi Noel

Not sure if this is any help but for several years we have used Aten/Vancryst 4 port HDMI switches for our repeater
https://www.aten.com/au/en/products/pro ... es/vs481b/ There is a + b models and also a new c
The repeater has a simple 8way CStech DTMF decoder, both are cheap and effective
https://cstech.co.uk/product/8-output-dtmf-decoder/

When the repeater turns on the HDMI switch sees the first available input, which is a perminately "ON" Raspberry Pi with test patern
Since the switcher has actual press buttons the 4 open collector outputs of the CStech decoder short each switch to earth which works well
There is also RS232 available, but we've never used it
It is recomended that all inputs share the same resolution/standard video and HDMI silver dongles used when sources/sinks don't behave

Our old setup had quite a long delay between input switching, our new one it's quite fast

Cheers Roger VK5YYY

g8gtz
Posts: 1548
Joined: Wed Apr 07, 2010 6:26 pm

Re: BATC ATV repeater logic software design

Post by g8gtz » Wed Jan 12, 2022 1:18 pm

Quick update:

Dave G8GKQ has made significant progress on the beta version of the controller software which was tested on the GB3HV net last night.

As Rob pointed out in a previous post, viewtopic.php?f=82&t=7092#p25696, the HDMI switcher must be "seamless" to avoid crashing the subsequent encoder.

Due to the complexities/reliability of controlling switchers via RS232, the default control method will be via infrared with the ability to program remote control codes into the RPi controller. The controller will drive an IR LED (from an old remote control) via a GPIO pin. Hardware control of older types of switchers will also be available using a number of GPIO pins.

As most seamless switchers only have 4 inputs, it will be possible to drive 2 separate IR transmitters allowing a 2nd switcher to drive the first switcher thereby providing up to 7 inputs.

A wiki page has been set up where full documentation for the project will be made available. https://wiki.batc.org.uk/Repeater_Controller

73
Noel - G8GTZ

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