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Forum Index : Microcontroller and PC projects : PicoTower II

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Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 6772
Posted: 01:32pm 06 Nov 2024
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More loopy stuff. :)

I like this. The Hammond 1593 isn't the cheapest or most available case out there, but the proportions are right for a miniature PC tower. You can also get it in white (close to "computer beige"), black (otherwise known as "plastic black") and a really cool translucent blue. It can also take PCBs in various useful slots, including inside the lid.

With that as a basis, and Javavi's wish for a dual VGA/HDMI capability I've come up with this.



Once again, the "44-pin Pico" makes life very easy. When you get fed up of it it's easy to snap off the extra pins. In the meantime it's still breadboard-friendly.

The drawing shows optional sub-boards in the lid, carrying a GPIO socket (connected via ribbon cable - they are aligned internally) and two WII connectors (unwired here). Another pcb on the bottom carries the voltage reg, reset button and two USB sockets. These are on the left-hand side of the case. Two MF hex spacers are used to allow the base to be screwed in, the PCB giving them some support.

The bottom and auxiliary boards would all come out of a second PCB, smaller than 100x100 (as is the main one).

The 5V rail to the linear regulator is from a diode-OR. One input is from the USB-C and the other is from VBUS. (Just noticed - I could have saved a diode by using VSYS). So, when programming, it doesn't matter how you power it.

There's some nice SMD soldering to get your teeth into on this one too. :) You could build it as VGA only though, in which case it's quite easy.
Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs
 
Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 6772
Posted: 07:18pm 07 Nov 2024
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Some tweaking.
By using a second PCB with a big hole in the middle of it, mounted on the LH side, it can be made very versatile. The hole allows some depth clearance and cooling, but also allows a ribbon cable or Dupont lead to be connected to either GPIO pins at the rear or a D9E connector and a WII connector on the front. You could also change it to do other things.

That makes the total build workable on three sub 100x100 PCBs. Only the front/rear panels one would need to be cut.

I've also added level shifting to the console connection so it's ok to use a standard Pico or a Pico 2.
Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs
 
Volhout
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Joined: 05/03/2018
Location: Netherlands
Posts: 4222
Posted: 08:18am 08 Nov 2024
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Hi Mick,

I see a potential volume conflict between the dual US on the side board, and the main board (the hub board).
I expect that you use 10pin flat cables to interconnect boards
I see no wires for the dual WII sockets to the main board.

All in all impressive that you used every single mounting post in the 1593 housing to screw to something. You have good 3D vision.

I wonder (with all the flat cables in) if you can close the housing. It will be cramped.

Volhout

P.S. A reset switch on the TOWER side may not be smart. When it falls over (pulling a cable) you loose current status. Actually (compliments to Peter) I think the reset switch is rarely needed, and when, you can always re-power. The only computer I know that has a prominent reset switch is the ACORDN ATOM (the BREAK key) that actually performs an RST of the 6502 processor (and the Game*Mite, where it is usefull, since the battery operation prevents you from re-powereing easilly).
Edited 2024-11-08 18:24 by Volhout
PicomiteVGA PETSCII ROBOTS
 
Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 6772
Posted: 09:02am 08 Nov 2024
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I'm now unsure about the full size board in the LH side. I did it to add stiffness when putting sockets on it, but it's massy and I forgot that I still needed the PCB at the bottom so it's not saved any PCB.

The reset button is positioned so that it is just below the surface of the case. The travel is very small as it's a tactile switch. At this point the case wall is about 2.5mm thick so I could recess it even further.

I *think* you could use ribbon cable on this, but I'd use Dupont connectors and flexible wire myself. It's more work but the resulting loom is usually more flexible. You'd have to do that when connecting the bottom board to the main one anyway as the connectors aren't aligned and there may be a problem in getting ribbon away.

Overall I'm not sure where to go with it at present. Possibly move the LED and SD card socket onto a LH sub-board and put any connectors on the main one, although it's much less flexible. I don't like the sub boards being on just 2 screws if there are sockets on them.

===========================

I'm tempted to use this SD card socket so that it looks a bit like a floppy drive. :) In spite of that the ad says it does not have a level shifter or voltage reg. I've had these before.
.
Edited 2024-11-08 19:44 by Mixtel90
Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs
 
javavi

Senior Member

Joined: 01/10/2023
Location: Ukraine
Posts: 203
Posted: 07:02pm 13 Nov 2024
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Cool! I like the PicoTower concept!
I especially like the full-size SD card, it's more convenient to use and looks very "retro", so don't change it to MicroSD (or make it optional somehow).
Of course, you can still think about the layout and figure out what goes where.
Edited 2024-11-14 05:07 by javavi
 
Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 6772
Posted: 07:52pm 13 Nov 2024
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I have one of these boxes in translucent blue. It's been very handy during the design of this as I can see where things won't fit. :) It's also *really cool* :).

I prefer to stick with the full size SD card. I measured up one of the others and it wouldn't fit anyway. I may leave the D connector off. It's not really needed as the PicoGAME HDMI has one plus a spare. :)
Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs
 
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