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Re: New project: An ACT Apricot F1 "barn find"
Posted: 18 May 2021 13:07
by rubber_jonnie
I'm sure you've already seen this, but thought I'd add it anyway:
http://www.computinghistory.org.uk/det/2729/Apricot-F1/
I find it slightly odd that they went for the IR KBD but since reading some stuff on it it seems it was partly intended for home use with a TV connection and the keyboard makes sense if you're sat on a sofa.
Re: New project: An ACT Apricot F1 "barn find"
Posted: 18 May 2021 13:26
by stephen_usher
Well, it's not really a home system. There was a modulator add-on for the machine but it wasn't standard. You have the normal Apricot TTL RGBI 9 pin colour output (H-sync/V-sync) and mono composite video otherwise. It is rather more stylish that the Xi/PC though.
Given how many people like wireless keyboards and mice these days I can see why the idea of a wireless keyboard would have been innovative and desired but the IR technology just wasn't up to the task. Only now with 2.4GHz radio and the processing power for the protocols required has allowed this to become reliable.
Re: New project: An ACT Apricot F1 "barn find"
Posted: 18 May 2021 14:08
by rubber_jonnie
stephen_usher wrote: 18 May 2021 13:26
Well, it's not really a home system. There was a modulator add-on for the machine but it wasn't standard. You have the normal Apricot TTL RGBI 9 pin colour output (H-sync/V-sync) and mono composite video otherwise. It is rather more stylish that the Xi/PC though.
Given how many people like wireless keyboards and mice these days I can see why the idea of a wireless keyboard would have been innovative and desired but the IR technology just wasn't up to the task. Only now with 2.4GHz radio and the processing power for the protocols required has allowed this to become reliable.
Yes, I agree, I recall a lot of stuff trying infra-red back in the day, and none of it being particularly successful. Sounds like fun and games building the IR adapter. Out of curiosity, is it bi-directional?
Re: New project: An ACT Apricot F1 "barn find"
Posted: 18 May 2021 14:31
by stephen_usher
No, purely unidirectional.
I've attached the schematic diagrams for the relevant part of the machine, i.e. the keyboard itelf, the IR receiver circuit and the interface with the Z80-SIO.
Note that the "2.5MHz" input to the 556 timer is actually 2.24MHz in reality.
f1-keyboard-decode.jpg
f1-keyboard-circuit.jpg
f1-ir-receiver.jpg
Re: New project: An ACT Apricot F1 "barn find"
Posted: 18 May 2021 15:01
by rubber_jonnie
I see the KBD uses a microprocessor (I guess microcontroller is closer to the truth), shame you can't just recreate the original.
Interesting stuff!
Re: New project: An ACT Apricot F1 "barn find"
Posted: 18 May 2021 15:19
by stephen_usher
rubber_jonnie wrote: 18 May 2021 15:01
I see the KBD uses a microprocessor (I guess microcontroller is closer to the truth), shame you can't just recreate the original.
Interesting stuff!
Yeah. Unfortunately it has an internal mask ROM and no information about the code.
Re: New project: An ACT Apricot F1 "barn find"
Posted: 18 May 2021 15:23
by rubber_jonnie
stephen_usher wrote: 18 May 2021 15:19
rubber_jonnie wrote: 18 May 2021 15:01
I see the KBD uses a microprocessor (I guess microcontroller is closer to the truth), shame you can't just recreate the original.
Interesting stuff!
Yeah. Unfortunately it has an internal mask ROM and no information about the code.
Shame the code hasn't been preserved somewhere. Good luck with your IR endeavours, it's very interesting as although I have a reasonable understanding of what components do and how computers function, I just don't have the skills to design something like that, I wouldn't know where to start!! Looking forward to seeing the results in action.
Re: New project: An ACT Apricot F1 "barn find"
Posted: 18 May 2021 16:16
by stephen_usher
OK. I *may* not need to do this. I've found an Apricot F2 for sale on Facebook Marketplace for £30 and I'm negociating to buy it... and it comes with a keyboard!
Re: New project: An ACT Apricot F1 "barn find"
Posted: 19 May 2021 16:01
by stephen_usher
Well, the F2 with keyboard arrived today, amazingly.
What was more amazing was how poorly it was packaged... Thrown straight into a flimsy box with no padding with a load of cables and then sent via ParcelForce!
It's going to be another case rebuild.
Re: New project: An ACT Apricot F1 "barn find"
Posted: 19 May 2021 16:05
by rubber_jonnie
stephen_usher wrote: 19 May 2021 16:01
Well, the F2 with keyboard arrived today, amazingly.
What was more amazing was how poorly it was packaged... Thrown straight into a flimsy box with no padding with a load of cables and then sent via ParcelForce!
It's going to be another case rebuild.
Good find, shame the seller couldn't be bothered to do a proper packing job :headbang:
Is the keyboard identical from an IR perspective?