Creating ASCOM + ASCOM/Alpaca drivers

[Grant Privett]

Has anyone on here been brave enough to write an ASCOM driver for equipment?

I am curious as to how hard it is to do. I believe V22022 and C++ are needed and I thought it would be fairly straight forward* but the developers make a big thing about not using dlls anymore… So I’m a bit stumped as to how it works. Use executables only it said – to avoid 32/64 bit issues apparently. Do they mean spawning/shelling an exe that does the job for every action, do-able but a bit tedious.

An example or two would be nice too.

If anyone has an example knocking about I would be curious to see it.

*though I’ve not touched C++ since 2005.

• This topic was modified 3 weeks, 2 days ago by Grant Privett.

[Mr Ian David Sharp]

Hi Grant,

Yes, I wrote an ASCOM Alpaca driver for my dome 2 or 3 years ago. I believe it was the first ever Alpaca dome driver. Works like a charm.

However, it was written in Python. It runs on a Raspberry Pi.

Ian.

[Grant Privett]

Morning Ian,

Thanks for replying. I knew there must be people out there that do this sort of thing but you never get to hear who they are as its a touch niche.

Python sounds great as my progression has been Fortran/Algol/6502/Z80/C/IDL/Python down the decades and I certainly have a spare RPi knocking about…

So, how does it work then? Does it, for every possible taskable type of instruction, issue a command line process calling a Python instance while perhaps storing info in files or environmental variables? I’m intrigued.

I’m fairly certain you can call dlls from Python, so this sounds hopeful.

The ASCOM/Alpaca website said newbies should use their templates – for fear of people picking up bad habits from others – but then failed to say where said templates were. It strikes me as site designed by enthusiasts for other enthusiasts and with way too few examples. Thats said, its a hell of a piece of work.

[AlanM]

Grant, this site may be of use to you.

https://github.com/ASCOMInitiative/AlpycaDevice

[Grant Privett]

Hmm. I shall have a look at that. Python is very easy so its an attractive option. Wonder if I should stick with ASCOM rather than Alpaca for simplicity but worried anything I do might become redundant in a few years if they are moving away from COM.

Oh well, no excuse then but to use github for the first time and try Visual Studio – which I downloaded years ago and got rid of fairly quickly after I tried to convert a GUI intensive VB6 program to .NET. It wasn’t a happy experience.

Truth be told, a large chunk of my last 10 years has been spent developing software for image processing pretty much in a team of 1. I wrote IDL (or later Python) and its run from command line. My understanding of the ASCOM/Alpaca/Github universe is wafer thin… 🙂

Looks like one of my old laptops is about to be resurrected for this. Be warned, there may be immoderate language…

Does anyone know if theres a latency issue with using Python rather than another language?

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