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rogs said:I think the problem here is the fact that the configuration is slightly odd. (Up to) 24 individual mutally exclusive input switches (possibly individually illuminated?) and only one output required (to drive a single bell activation relay).
rog said:Not difficult of course, but the peripheral 'glue' needed to interface that configuration with most simple uCs will require almost as much hardware as simply doing it in hardware anyway!
he ability to address up to 24 individual '16 bit' binary sequence outputs is not exactly going to tax the capabilities of a modern uC....
24 momentary switches can easily be setup in a 4x6 array using 10 I/O pins and no additional ICs.
Yes, I'd agree entirely. I've emailed a railway technician I know - he's never actually had anything to do with these bell instruments, but knows a few people that have, so he is going to ask and come back to me - that should get it defined once and for all.I kinda thing the current is a lot higher since you used a car battery, I remember a car tape-deck/car radio i worked on needed a pulse of 10 Amps to switch.You kind need to get a handle on the voltage and current requirements.
I figured I gave you enough stuff to process.
How is your soldering skills and could you build a small protoboard project?
Connectors are an important part.
Certainly those samples seem to have a typical 'gap' timing about the same spacing as the bell.
Although of course the monostable connected to the multiplexer output needs to be adjusted to allow the bell 'hammer' (solenoid?) to strike, and then fall, much more quickly than the whole time period, to allow the bell to sound 'right'.....(just a short 'ping' of 100 - 200 mS, I suspect?)
So, it would simply be a question of adding longer programmed sequences into the flash. (say 32 per sequence instead of 16?). You could go further and make it 64 -- there are plenty of counter outputs, and spare flash locations to address!...
It doesn't look like the OP adequately described the problem.
Re: the timing..... the few examples I have heard online don't suggest it's that critical (the sequences were entered by hand.... like manually keyed 'Morse Code', as you suggested.)
..... I'm no expert at electronics, I just wanted to find the best way of getting an outcome for the project and maybe learn something at the same time..... What I don't want to do is to find an outcome and have absolutely no idea how it works or does what it does, I need to understand it - a) for troubleshooting, but more importantly b) for future reference, and doing other things!
@ rogs
I've been suggesting individual switches, you have been suggesting multiplexing switches.
.......He is apparently in the uk........