The Worlds Smallest Atari 8-Bit?

[+slx]

20 hours ago, Mr Robot said:

It going to be a 1 and a 0, VIDEO is going to say MON as its a monitor and audio outputs. 

I'd suggest to use a very plain I rather than 1. Should make less fuss with printing and is a good symbol for a closed connection.

[Mr Robot]

All the text uses Harry Fat, the 1 is pretty minimal.

[+slx]

Why does it use 12V rather than 5V?

[+DrVenkman]

12 minutes ago, slx said:

Why does it use 12V rather than 5V?

Basically because 12V DC power supplies are ubiquitous and super cheap.

[Mr Robot]

Also plugging 12v into a 5v device will kill it, plugging 5v into a 12v device will not, so it's safer... just stay away from 24v supplies  

[+slx]

14 minutes ago, Mr Robot said:

Also plugging 12v into a 5v device will kill it, plugging 5v into a 12v device will not, so it's safer... just stay away from 24v supplies  

Does that mean I can't power it from a plane's cigarette lighter?

 

And how much damage to be expected from plugging in a 400/800/810/1050 9V AC supply?

 

Got to stop keeping you from finishing this....and me from preparing for Christmas...

[Zonie]

Try a space between each letter on Fujinet. It will print cleaner.
F U J I N E T

 

Edited December 20, 2020 by Zonie

[+mytek]

1 hour ago, slx said:

Why does it use 12V rather than 5V?

Mainly because I wanted to implement a more stable color adjust circuit then resorting to a voltage doubler as done in a stock Atari. Many might not know that GTIA's color adjustment pin needs a higher voltage than the logic 5V normally available. So a diode/capacitor charge pump circuit is used to boost the logic voltage up to between 8-9V for this purpose. However the derived higher voltage is very much influenced by the voltage output of the 5V PSU, if it shifts so does the color. Many of the newer compact power adapters use switching voltage regulation technology, and tend to take over 30 seconds to fully stabilize, whereas the original Atari PSU uses linear voltage regulation and usually stabilize much faster. It was during the 1088XEL that I noticed this problem which required waiting maybe up to 1 minute for the color to settle in.

 

What was the solution I used in the 576NUC+ ?

 

I incorporated a precision temperature compensated 10V regulator into the color adjustment circuit.  This required that the incoming voltage needed to be at 12V or higher for proper regulation to occur - hence the 12V PSU. Now I could have achieved the same thing by using a voltage tripler feeding the 10V regulator, but that would have required a lot of discrete components which I really didn't have room for in my design.

 

The 12V is also available from the SIO connector as an always powered supply, which if connected to a suitable 5V regulator could serve as a supply for an SDrive, assuming custom SIO wiring was used.

 

Edit: been kicking around the idea of assigning always on 5V power to one of the extra pins on the Dsub-15 SIO jack. Then with a custom cable an SDrive could be always powered independent from the NUC - no extra PSU required.

 

[BillC]

4 hours ago, slx said:

And how much damage to be expected from plugging in a 400/800/810/1050 9V AC supply?

The power supply circuit has a diode to prevent damage from an AC or reverse polarity DC power supply being connected!

[BillC]

6 hours ago, Mr Robot said:

just stay away from 24v supplies

A 24V power supply shouldn't damage the main chips, the recommended rating of the 5V regulator Michael chose is up to 28V (30V maxiumum), the capacitors before the regulators would be an issue and require a high enough voltage rating. As this is a switching regulator the higher input voltage shouldn't have any significant affect on power dissipation/heat.

 

A more significant problem would be with the LM4040 used for the color adjustment circuit, it is only rated at 15mA and would be passing over 90mA(14/150) to maintain 10V with a 24V supply and would probably fail quickly.  Increasing R26 from 150 ohm to 1k ohm would limit the current to 14mA @ 24V, this would reduce the current to only 2mA @ 12V but the LM4040 minimum current is listed at only 60uA. The current through the color adjustment potentiometer is only ~20uA, so this resistor change shouldn't cause any problem.

 

This would only leave the +12V output on the DA15/SIO port as an issue, there are very few peripherals that use this as it was only available on the 400/800 computers.

 

EDIT: With a +12V power supply the voltage can be as low as +11.5V caused by the voltage drop of the SB240 polarity protection diode.

Edited December 20, 2020 by BillC

[+mytek]

2 hours ago, BillC said:

The power supply circuit has a diode to prevent damage from an AC or reverse polarity DC power supply being connected!

Yep .

 

1 hour ago, BillC said:

A 24V power supply shouldn't damage the main chips, the recommended rating of the 5V regulator Michael chose is up to 28V (30V maxiumum), the capacitors before the regulators would be an issue and require a high enough voltage rating. As this is a switching regulator the higher input voltage shouldn't have any significant affect on power dissipation/heat.

 

A more significant problem would be with the LM4040 used for the color adjustment circuit, it is only rated at 15mA and would be passing over 90mA(14/150) to maintain 10V with a 24V supply and would probably fail quickly.  Increasing R26 from 150 ohm to 1k ohm would limit the current to 14mA @ 24V, this would reduce the current to only 2mA @ 12V but the LM4040 minimum current is listed at only 60uA. The current through the color adjustment potentiometer is only ~20uA, so this resistor change shouldn't cause any problem.

 

This would only leave the +12V output on the DA15/SIO port as an issue, there are very few peripherals that use this as it was only available on the 400/800 computers.

 

EDIT: With a +12V power supply the voltage can be as low as +11.5V caused by the voltage drop of the SB240 polarity protection diode.

All true, but let's not be connecting 24V in the first place, since the input cap is only rated for 25V .

 

I have since removed the always on 12V (11.5-11.7V) power from the Dsub-15 equivalent to the 12V pin of the stock SIO, and moved it to one of the outside pins of the Dsub-15 instead, along with adding the always on 5V to the other outside pin. So for a customized SDrive connection, you could use a Dsub-15F on the SIO cable and route a separate wire from pin 8, connecting that inside the SDrive enclosure where external power would normally go.

 

[BillC]

40 minutes ago, mytek said:

All true, but let's not be connecting 24V in the first place, since the input cap is only rated for 25V

Why not idiot proof the circuit if it doesn't increase the price significantly.

 

Changing C1/C2/C3(the rest of the capacitors appear to be on regulated voltage) to 35V and R26 to 1000 or 1500 ohm would prevent damage if a 24V power supply was connected by mistake, at minimal cost unless parts have already been ordered.

 

Increasing the resistance of R26 reduces the current through the LM8040, which reduces its power dissipation and will likely increase lifespan. The lower current supply through R26 shouldn't have any affect on the color adjustment circuit.

 

[+mytek]

3 hours ago, BillC said:

Why not idiot proof the circuit if it doesn't increase the price significantly.

 

Changing C1/C2/C3(the rest of the capacitors appear to be on regulated voltage) to 35V and R26 to 1000 or 1500 ohm would prevent damage if a 24V power supply was connected by mistake, at minimal cost unless parts have already been ordered.

 

Increasing the resistance of R26 reduces the current through the LM8040, which reduces its power dissipation and will likely increase lifespan. The lower current supply through R26 shouldn't have any affect on the color adjustment circuit.

 

The resistor change is easy, and as you pointed out wouldn't affect the overall circuit. However I will have to see if a 35V capacitor of the same value would fit in an already tight spot. If it's possible I'll make the change. Thanks for the suggestions  . But what if someone uses a 48V supply  . You can't completely eliminate all the foolish ideas, or protect yourself from them.

[+DrVenkman]

7 hours ago, mytek said:

But what if someone uses a 48V supply  . You can't completely eliminate all the foolish ideas, or protect yourself from them

Besides, how many people have 24V power supplies sitting around? All the wall warts I have around here are 5VDC, 9VDC and 12VDC. 

 

As far as idiot proofing, maybe Michael could incorporate a small water-wheel inside, hooked up to a generator?  You know, just in case someone tries to power it with a garden hose?

[ZuluGula]

On 12/19/2020 at 8:48 AM, Mr Robot said:

I love the authentic 1050/800XL style switches and I've got a few here so I could have used one but they cost ~$8 each and that seems too much to add to the cost of a fujinet board that has an alternative available with a ceiling price we have to be able to come in close to.

https://lispol.com/produkty/przelacznik-kolyskowy-katowy-on-on-czarny-2a250v-80211

https://lispol.com/produkty/przelacznik-kolyskowy-katowy-on-on-czarny-15d58-80236

 

This is a store in Poland, that have both floppy drive and computer switches for under 50 cents.

It could be worth with shipping, if you order bigger quantities.

[+mytek]

5 hours ago, DrVenkman said:

As far as idiot proofing, maybe Michael could incorporate a small water-wheel inside, hooked up to a generator?  You know, just in case someone tries to power it with a garden hose?

Wow never thought of that  . It'll be a GREEN environmentally friendly NUC+ for sure with that add-on  .

 

In all seriousness, I have put a lot of thought into this new little Atari, listened to feedback from you all, including my BETA test team. I'm now on the verge of having a forth prototype board manufactured, and if my recollection is accurate Mr Robot is on the 3rd NUC-Fuji board design. There comes a point in time where the design needs to get locked down, despite what others want to see added or changed. We are pretty much at that point. Time to stop the wallet bleed.

[Mr Robot]

To be fair one of those Fujinet board revisions was unavoidable as we moved from v1.0 to v1.3 of the Fujinet schematic. But yeah, I have a growing collection of spare 'earlier' pcb's.

 

Order five, use one; iterate.

 

You should see the ever growing box of wasted PLA!

 

[ZuluGula]

You can recycle plastic.

[Mr Robot]

You can, but PLA is not your average plastic, it's a partially biodegradable thermoplastic and domestic recyclers cannot recycle it. Adding PLA to your domestic plastic waste ruins the entire batch because the recycler has no way to get it out of the other plastics so please, don't throw it out with other plastic waste.

 

The only current ways to recycle PLA are to give it to a recycler who knows how to deal with it or recycle it at home. The first option is easy but it does involve you doing some research and taking a semi regular drive. The second option is much harder, involving all sort of extra equipment that currently doesn't work very well for domestic use. There are companies who will take your PLA and turn it back into filament for you but it's currently so expensive it's cheaper to buy new. 

 

In the future, home recycling into pellets is probably going to be the solution, but that means having a pellet printer instead of a filament printer to reuse it or a pellet extruder to make it into filament and that is very hard to do at home. In the meantime, my box of waste PLA is ever growing.

 

 

[+Stephen]

1 hour ago, Mr Robot said:

You can, but PLA is not your average plastic, it's a partially biodegradable thermoplastic and domestic recyclers cannot recycle it. Adding PLA to your domestic plastic waste ruins the entire batch because the recycler has no way to get it out of the other plastics so please, don't throw it out with other plastic waste.

 

The only current ways to recycle PLA are to give it to a recycler who knows how to deal with it or recycle it at home. The first option is easy but it does involve you doing some research and taking a semi regular drive. The second option is much harder, involving all sort of extra equipment that currently doesn't work very well for domestic use. There are companies who will take your PLA and turn it back into filament for you but it's currently so expensive it's cheaper to buy new. 

 

In the future, home recycling into pellets is probably going to be the solution, but that means having a pellet printer instead of a filament printer to reuse it or a pellet extruder to make it into filament and that is very hard to do at home. In the meantime, my box of waste PLA is ever growing.

 

 

Just burn it for heat - it is the winter time in most of the USA.  Two problems solved at once!

[Mr Robot]

Latest beta print of the XE case, skull logo on the top.

 

[+mytek]

3 minutes ago, Mr Robot said:

Latest beta print of the XE case, skull logo on the top.

?????

 

[ajacocks]

Looks absolutely fantastic!

[The V-Man]

That is great!! 

[+slx]

16 hours ago, Mr Robot said:

You can, but PLA is not your average plastic, it's a partially biodegradable thermoplastic and domestic recyclers cannot recycle it. Adding PLA to your domestic plastic waste ruins the entire batch because the recycler has no way to get it out of the other plastics so please, don't throw it out with other plastic waste.

 

The only current ways to recycle PLA are to give it to a recycler who knows how to deal with it or recycle it at home. The first option is easy but it does involve you doing some research and taking a semi regular drive. The second option is much harder, involving all sort of extra equipment that currently doesn't work very well for domestic use. There are companies who will take your PLA and turn it back into filament for you but it's currently so expensive it's cheaper to buy new. 

 

In the future, home recycling into pellets is probably going to be the solution, but that means having a pellet printer instead of a filament printer to reuse it or a pellet extruder to make it into filament and that is very hard to do at home. In the meantime, my box of waste PLA is ever growing.

 

 

The city where I live is very "waste-conscious" and operates a huge waste removal/recycling/dump/incineration department. They have a "waste hotline" and when I started 3D printing I asked about the PLA waste. They were not aware of it but after some research got back to me and told me to put it into the regular waste bin where it's either dumped into a landfill (actually a new hill as we live on mostly flat land) or incinerated.