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Having purchased a couple of Bright-Tech flip dot displays on ebay I am on a mission to bring these back to life
A few people have reversed engineered the Hanover displays allowing them to be salvaged and re-used by hobby electronics people, my example a 'world clock' for work: World Clock using Hanover Display.
But I have found very little about Bright-Tech units...
The original company folded in about 2010 and there is a company that services the remaining units (Candella) of which there must be thousands in the field! ... So as the vehicles age and are replaced there must be a hackers/hobbyist market out there soon!
My starting point is the 2 displays I have + the efforts of Matt who started looking at the protocol but than abandoned that in favour of building his own control board (very nice but high effort).
So I'm going to reverse engineer the language of the controller and hopefully make these easier to use
Read my efforts to reverse engineer the protocol (please let me know anything else you find!)
Go to the Summary of what I know so far (can you help expand this?)
The display units are designed for use in public transport vehicles or train stations and bus stops. They come in both LED and flip dot types or a hybrid BrightDot type that is a flip dot with an LED under each dot.
I'm mostly interested in the flip dot types of display which are rather pleasing to watch changing, but what I've learnt here about the protocol and connects will no doubt work for the LED types as well.
Designed for use on bus and coaches the display runs at 24V DC and communicate over RS485
RS485 is a standard for connection it is not a protocol basically it is RS232 'standard serial' but signalled with a differential voltage on 2 wires. this makes it much less prone to noise and can travel over wires perhaps 1km long. It is used in industry, motorway signs, public information signs and transport i.e. low data rate but quite harsh environments.
You can find cheap RS485 USB dongles on ebay and amazon, but be aware that many don't play well with windows 10. you can also find transceivers that take TTL levels and convert to RS485 this is the sort of thing an Arduino user might think about.
You might get away with 12V supply? I have not tested this. I've run the display as low as 19V, an old laptop power supply is ideal for this if you don't have a bench supply to hand, of course I would never exceed the 24V rating and don't get the wiring wrong (although it looks like there is a diode in the display I have to protect against this)
Each display has its own address which is set by switches under the back cover, the board is also covered in jumpers that probably change behaviour and enter other test modes for servicing, I have not played with any of the jumper settings only the switches.
The address selection switch also enables a number of short test modes on the display which then active when the unit is powered up
I strongly advise you to power off the display before opening the back to change any settings and take some simple static precautions, these things are robust but a zap of static could kill the CPU
Dip switch settings 6 bits
- bits 0-3 value 0-F 1-F = address not sure about 0 ?
- bits 4-5 select various test modes in combination with 0-3
TODO list the test modes that I have found and detail address range
0 - not valid
1-F address of display (1-3 confirmed, assuming up to F ??)