Another (winter) new project

Nope, unfortunately not finished! It's as is. We all know that real life can alter one's schedule. That's what it did to me. Shortly after my last posts i went through a divorce, then me mum passed away, health problems, second marriage, grand-daughter, and to finish it all up.... capital controls!
One of the reasons (actually main reason) i'm not yet fully back to speed is capital control. We're not allowed to spend currency outside the country for quite some time now. Which means i can't order stuff either through ebay, or purchase stuff here. Only backdoor solution to that is if i can sell stuff and keep my prepaid card 'loaded'. That's the only reason i've been trying to sell things here, as much as i hate to. All my projects are at near halt now, except the cockpit, and i'm a bit lucky on that because lots of parts are scratch-built. I've been planning to replace the original Pi on this project with the 3rd generation Pi, but you see that's near impossible... Thus, if things change, maybe i'll get back to it.

After quite some time of being in a pause, this project has started again... I managed to get me a Pi3, and here's some things i've been doing:
Got me a plastic basket...

Color near matches the case.
Cut part of it:

Had to build a frame, due to monitor being smaller than the old monochrome LCD.



Some trimming will be required, but not in a rush.
Here's the 7" monitor:




And here's a rough idear of how it will be installed:


Next, i had to remove the original pushbuttons, and install ones with a longer lever.


And drill holes for them:






And that's just about it for the time being! I've got me two MicroSD's, one for a Retropie installation, and one for an AmiBerry installation. Both environments seem to be working a-OK. I also purchased a USB floppy drive, which i hope to be using for loading .adf images in AmiBerry. Just for retrolicious feeling's sakes. Plus i got me a new microSD extension cable, so i can exchange cards externally.

Here's another update. I just now finished installing the display into the frame, and did a power-on test.






The monitor needs a little trimming of its position to the right, but that's a piece o' cake.

Done testing the Pi with the monitor. Pictures are from both environments: RetroPie, and AmiBerry.

Not much news on this project, but i have a question: can anyone suggest a proper switch that would allow me to switch between two power sources on the Pi? I need to be able to switch between the actual power supply and the solar panel. This means i need a switch that can open and close two sets of 4 contacts, preferably a slide switch, of the ON/OFF/ON or ON/ON nature. I've seen some, but could find no schematics..

Some progress reported on the keyboard. First, i tested Leds to see that the pcb is operational:



I then drilled three holes on the casing for the Caps, Num and Scroll Lock indications:



Next, Leds were soldered to the pcb:



All Leds working!



And here's the keyboard in all its glory:



Tested on the Pi, and it works A-ok.

And another small progress. Built a pcb for the Ethernet extension.







Then put some spacers for securing the Pi:





Last, i cut some plastic for fascia to cover the Ethernet socket:









And that's just about it for now..

Did some cleaning on the plastics, and some partial assembly. This is the result so far:









I have ordered some stuff, and am waiting for their arrival. Things include a stepup transformer for 5vdc to 12vdc (monitor supply), a low-power audio amp for installation of speaker out from the Pi, and various bits n' bobs.

The powered USB hub i had, was disassembled, exposing its pcb:





Then i cut some plastic for fascia:





And made a wooden base with vertical stop at the rear to prevent the pcb from moving when USB cables are inserted:





Here's what it looks like now, but plastic will be cut in height:

I know it's been a rather long time, but i haven't quit on this project. Lots of progress so far. First of all, it gave me a real hard time to transfer various files from Photobucket over to Postimg. Anyway, i have initially used the composite display, but i was not much satisfied of the results. Here's some examples:















Although it's much better than watching on a crt with an A520 modulator, it really looks so due to screen size. There's ghosting, and when in 'terminal' mode on the Pi, you can have a hard time reading text.
Thus, i made a big decision and purchased an HDMI panel, same size, with a HDMI/VGA/AV controller. I removed the old panel and controller, and replaced them with the new gear.
Here's the controller, sitting under the display frame, inside the case of the laptop. I'll figure a way to secure it even better than with a thermal glue soon.



And this is the new display in place:



It needs a slight repositioning rotation to the left by a degree or so. :



The marks on the display are from the protective membrane it came with, no damage to the actual screen. But you can see that the image is WAY better, and pleasantly readable!
Here's Deluxe Paint menu on closeup:



I can assure you that my phone camera isn't doing it justice. Another thing i was worried about was the positioning of the displays' controller. But that's the only place it could be located due to its ribbon cable. The Pi is actually just under it when the case is closed. Here's the situation:



Luckily, the two boards have a gap of about 5 mms between them, and they would've have even more if i hadn't attached the heat sinks on the Pi. Well, that's all for now!

Some more progress on this, i forgot to mention yesterday. I got me an audio amp, to connect to the Pi's audio out, driving two 4cm 8Ωm speakers.
Here's the circuit:



I removed the volume knob, and after some filing, fitted the original Amstrad volume knob on the pot.



Then cut a piece of pcb, to replace the existing pcb:



and drilled it to let the pot shaft go through.



Afterwards i desoldered the pot from the circuit, and made some extension cabling to make room for the pot:







I also got me a Pi PowerPack, which includes a 3.7V 3800 mAh battery and a charging circuit.





Makers say it gives about 8 hrs of operation to the Pi, but people witnessed even up to 10 hours, depending on usage (wifi, peripherals etc.). Combined with a display panel it makes about 3 hours, but i'd be happy if i get even 2 hours! LOL. It's supposed to charge even when the Pi is operational. We'll see about that.

Some more progress on the project! Last night i managed to test using the battery pack with the whole gear. Here's the machine with its guts out, working for around half an hour on battery power:



I also tested the audio amp circuit, but it outputs a very low volume signal, dunno why yet.



Maybe there's a default (?) volume level on the DietPi OS, i have to find out what gives with that..
Next thing i noticed is the yellow thunder icon on the screen. After searching a bit, i found out that it's not a battery-mode indication, but a low power signal for the Pi.
Truth is, the battery was used as it came out of the package, without a charge yet. I will charge it fully and see again. But maybe it's a sign that using the Pi, LCD and audio amp all together draws too much current. We'll see, but the fact that this gear worked together for half an hour already, is a plus.



Stay tuned!

Started drilling the case's side for the second speaker's grill:


Also cut a slot for the microSD reader extension:



I also built a small pcb to host the microUSB female port for the AC adapter:



Felt like popping my eyes out to solder this, and after completion (better late than ever) came up with a thought: What if there is already a solution out there?
And there was! So i decided to get this:



Here you can see the microUSB power receptacle, the composite video in, and the ethernet port:



And an outside view:



After having successfully tested the subsystems, i need to tidy up the cabling:



But there's still a lot of work involved..

Next up, i wanted to save some space and gain flexibility all around, thinking that when i have to split open the case, the cables need a means of fastening-disconnecting. Here's the monitor control pcb that carries the buttons and led. I first removed the plastic connector:



Then split the cable in two parts that connect by means of a DIN-9 connector:





I also replaced the microswitches with ones that have a longer shaft. That was needed because the original ones were very short for the case.



And last, i placed another gray plastic sheet on the case opening, so i could secure the pcb there:



Also started tidying up the cables inside the case.

Had someone over at geekhacks trying to do the same thing, who suggested replacing the Lenovo keyboards' plate with the original Amstrad, and keep the USB circuitry and membranes. Thus, i tried it. I first cut part of the right corner, for the plate to fit next to the controller pcb:



Looks to fit real nice.





However, the Amstrad keyboard is very different from the Lenovo one, because the latter has plenty of additional keys! Also, Alt Space and Enter do not fall on the correct contacts. Thus, the swap is canceled. Maybe i'll be lucky enough someday, and find similar keycaps, but no harm done..

Next up, i decided to install an HDMI splitter circuit. I just might use the onboard monitor for other inputs. So, i transferred the LEDs and switch from the device to a small pcb. Actually, the switch is a different one with a gray button to match the case batter.





Placed the splitter in the case. The white flat ribbon cable is the microSD extension.



This is how the side of the machine looks now:



Was looking for a gray dossier, but could only find a black one. I cut a strip from it:




I wanted to make the screen frame look nicer, covering the ex-button holes.



Here's the before and after comparison:



Dare i say it looks sexier?

- - - Updated - - -

Also got me some rectangular LEDs, to place in the original sockets:



However, the led sockets aren't the same size for all indicators..



So i made a small pcb adding two regular LEDs inbetween.





Also added resistors to protect the Pi:



And finally fastened the whole thing in position.

Love it !! Keep up that good work.

That little audio amplifier - is it a class D chip amp ? If not - well it should be ! The class D ones have much lower current consumption, and usually have a "sleep mode" that makes the crrent consumption drop to micro-amps. The class D ones (can't remember the chip numbers now, but one is PAMXXXX) can be had for loose change from China .... and work really very well.

The battery - is that a tiny PCB mounted on it ? If so - that'll be a BMS circuit - to stop over-charging and cut-off when voltage gets too low - usually between 2.5 - 3V .
Ideally those lithium batteries should be stored (if not in use for a while) at about 50% capacity = about 3.75-3.8 V

@slaz: Thanks for your comments and suggestions! The audio amp's description is DC1.8-12V TDA2822M Amplifier Module 2.0 Channel Stereo. I highly doubt it's a class D one, but surely worth some pocket change. Will consider the class D circuits though, the less current, the better!
The battery pack is the blue pcb, having the lipo underneath it. It supposedly has a charging logic, and can operate simultaneously with the AC adapter. All tests have been conducted with no charge at all, exactly as i unboxed it. I have still not charged it even once LOL.

Have a look here ...

https://www.ebay.co.uk/itm/2x3W-Min...hash=item36192051a1:m:me6baAB_vg6dbydVOWfNM0w

There's a few variants e.g. with/without POT etc. Also other variants of PAM chip.
Looks like your TDA2822M amplifier is class AB - so certainly less power-efficient.

Oh yeah ... in case you're not au fait .... Lithium cells (well certainly LiON and LiPO) need a 2-phase charge cycle - first comes the constant current phase - until the charge voltage reaches 4.2V - then goes to constant voltage phase - stays at 4.2V with diminishing current until battery is deemed to be "full".

I have ordered a class D amp with pot, it's waiting time now.. Did a test with cables on the GPIO, to see if the Power indicator would light.



Seems to be ok so far, next time around i will have to test the Act indicator, but that seems to require some script to enable.

Does anyone have any experience with USB floppy drives on the Pi3? I've been using the AmiBerry environment based on the DietPi OS, and when i go to the .adf menu trying to load an adf image from floppy, the drive light goes on, and the system gets stuck. Of course the diskette is pc-formatted, and i highly doubt it's a power issue, because its behaviour is the same with or without extra peripherals on the Pi. The psu is the original 2.5A.