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Entry 19: Pick a Peck of Pickled Prototypes

A project log for Aiie! - an embedded Apple //e emulator

A Teensy 4.1 running as an Apple //e

Jorj BauerJorj Bauer 02/20/2018 at 01:102 Comments

JOSS is going to take a while. Yes, it's seen the light of day, proving to me that it's possible. But there are so many pieces that I still need to code - and I'm not sure how feasible it's going to be to get the Wifi driver and USB stack written. I'm (sensibly, perhaps) keeping this in my log of to-do items as future work, and moving forward with development under Linux until I've at least got the hardware settled.

And to settle that, I need to actually make a decision about the hardware. Which is turning out to be difficult.

First: I've got a pile of different LCDs now lying around. Two different serial 320x240s. One 3.2" 480x320. One HDMI 3.5", and one HDMI 5". Each has its pros and cons.

I've also got designs on three different form factors. Two of them I can envision in cases. The other one is still basically the same device I've already built - but faster.

And continuing with the Pi Zero, I still need to build the end of the peripherals; one serial port for the printer, and two analog inputs for the joystick. Oh, and probably a third analog input for the battery level sensor?

I spent a good deal of this past weekend with papercraft and woodworking to mock up what various things would look like. It was a good use of time, even if there's nothing permanent that came out of it; my thoughts are more solid about what I want, at least.

The three prototypes I have right now are:

1. The "classic" Aiie prototype. Exactly the same form factor as the original. Small 1cm buttons as "keys" for the "keyboard" (button pad). 3.5" LCD -- probably a very nice HDMI jobbie I found on Amazon, this very nice $30 3.5" downconverting display. The LCD it's attached to is only 320x480, but it scales the HDMI input down very nicely. Power draw is pretty reasonable, too. Or, if I spend time on it, this could still be one of the 3.2" serial LCDs with a Teensy 3.6 (and external RAM).

Or, prototypes 2 and 3... a scaled-down Apple //e style -- based around either the 3.5" display or a 5" display. I really like this idea, but I want it to be functional. No fake keyboard, for example. If it's got a keyboard, then I want it to work.

And that kind of drives the direction a bit. The smallest working keyboard I can build right now would mandate a 6.5" wide model, so the 5" display *might* do. Or it might be a bit small.

In the other direction, using the 3.5" display I'd have to have keys that are about 0.2" wide. With SMD switches, I suppose it's possible; it doesn't seem like fun, and I have no idea how I would make key caps at that scale. It would be the cutest option, of course. So i'm still thinking it over (and if any of you have thoughts on a keyboard at this scale, drop me a line!).

Back to the visuals, though! I wanted to see it. And here's the 3.5" scale monitor, in papercraft form.

That's the 3.5" HDMI panel, sitting on top of a Pi Zero, connected to a battery pack and a full-sized keyboard. You want to see it running, you say? Okay...

Amazingly cute.

I went through the exercise of cutting out the whole monitor at that scale before I realized that I couldn't build a working keyboard at the same scale. (I didn't bother taking pictures, sadly.) Then we moved on to the version scaled around the smallest keyboard I can realistically build...

First I mocked up the keyboard, then built up to the monitor. The 5" LCD I've got is a bit small for it but I think it's workable. To get a better idea of it, I threw together a quick plywood mock-up...

Yeah, that might work. There are a lot of details I'll want to build out in that direction, but I'm pretty happy with the display. Out the back comes an HDMI input and power; this panel has no audio, unfortunately. (The 3.5" one does. Have I mentioned I really like that 3.5" display?)

So I'm going to focus on this case for the moment. (I'm starting to think that it's going to be impossible to pick one; it's probable that I'll wind up building this multiple times at different scales...) Some HDMI connectors are on order, and the weather is almost warm enough for me to start fiberglassing again!

Discussions

Charles Mangin wrote 06/07/2019 at 18:31 point

If you're interested in 3D printing the monitor and case, or just want references, I've modeled them on Thingiverse:

https://www.thingiverse.com/option8/designs

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clae wrote 05/11/2019 at 09:53 point

I'm partial to a mini Apple IIc look myself - IMO your original board with the integrated keypad is ideal for that.  It even looks like the right proportions, from a rough eyeballing.

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