The RPi400 motherboard should be sold separately

[Botspot]

It would be very nice if the Pi400 bare PCB was available for sale separately.
This size and shape would make it ideal for many new projects.

It's slim but has all the ports, making it perfect for DIY Pi laptops, tablets, maybe even clusters. (if the CM4 isn't your style)

paulhothersall agrees.

please sell just the board as a SKU, perhaps with stick on heat sinks.

Its a pi with all IO on one side. this is a huge win for many many projects. I can already see me getting a bunch of these, especially with the higher clocked CPU helps, and it will be eWaste just to toss the keyboard for them.

[hippy]

Being sold separately would be useful IMO; for people who want to use that board in their project, and to give users who blow up their board a repair option so they don't have to throw the entire Pi 400 away.

Anyone wanting to use the Pi 400 board in their project could buy a Pi 400, remove the board and throw what they don't need away, but that means more avoidable pollution.

[MikeDB]

I tend to agree on this. There's lots of projects where being able to mount a Pi directly in the back of a 1U 19" rack mount unit with the sockets facing backwards without adapter PCBs or cables would be most useful.

Please consider it once the initial rush on Pi400s has died down.

[DougieLawson]

I think it's clear that the Pi400 was released eight weeks before Xmas (and ahead of the Thanksgiving/Black Friday rush to spend money) for obvious reasons (and there'll be a large number of Pi400s on Santa's sleigh). Your pink ponies and unicorns request for a bare board version won't happen before 2021, if at all.

[fruitoftheloom]

.
Definitely not, it is limited compared to the 4B or CM4...

...CM4 Base Board would be a better solution.

[hippy]

.
Definitely not, it is limited compared to the 4B or CM4...

...CM4 Base Board would be a better solution.

That depends on what use case a potential user of a Pi 400 board has. Some may consider it simply as a Pi 4B 4GB with a more convenient connector layout. Being "limited" is entirely irrelevant if what something else has isn't required or desired.

There are a number of reasons I am leaning towards using a CM4+CM4IO to build a boxed Pi PC around rather than a PI 400 board, but I could see why some would favour using the Pi 400 board. If a Pi 400 board were available in its own right at the right price I could swing that way myself.

Ultimately it's up to individuals to decide what is best for them.

[jamesh]

Seems like a good idea to me, have passed it on. Won't be for a while though, if at all.

Whilst a cut down CM4 base board of similar size might offer a bit more in features, is doesn't yet exist...

[hippy]

Considering just board functionality, based on Foundation suggested retail pricing, using a CM4 Lite board supporting SD Card rather than eMMC coupled with a CM4IO board, the costs for equivalents break down as below -

Code: Select all

.-------.--------. .-------.--------.--------.
| Wi-Fi | Memory | | Pi 4B | CM4+IO | Pi 400 |
|-------|--------| |-------|--------|--------|
|       |  1 GB  | |  $35  |  $65   |        |
|  Yes  |  2 GB  | |  $35  |  $70   |        |
|       |  4 GB  | |  $55  |  $85   |  $70   |
|       |  8 GB  | |  $75  |  $110  |        |
|-------|--------| |-------|--------|--------|
|       |  1 GB  | |       |  $60   |        |
|  No   |  2 GB  | |       |  $65   |        |
|       |  4 GB  | |       |  $80   |        |
|       |  8 GB  | |       |  $105  |        |
`-------^--------' `-------^--------^--------'

Of course, none are exact equivalents.

Only the 4B has a composite video and analogue audio output connector.

Only the CM4+CM4IO has full-size HDMI sockets, PCIe connector, supports an external Wi-Fi antenna, has a fan connector, and an on-board RTC. It only has two USB 2.0 sockets, a header for two more, doesn't provide USB 3.0 sockets. It uses a 12V barrel connector for power rather than 5V USB-C.

The Pi 4B and CM4+CM4IO supports PoE while the Pi 400 does not.

The Pi 400 with its large heatsink is rated at 1.8 GHZ operation, the Pi 4B and CM4+CM4IO at 1.5 GHz.

All three have differing connector and 40-way header placement. The CM4+CM4IO and Pi 400 have all their primary connectors along one edge, are larger boards than the Pi 4B. Only the Pi 400 is able to disconnect the 5V supply to the 40-way header. It is also the only one which doesn't allow back-powering through that header. The Pi 400 doesn't have CSI or DSI connectors. The CM4+CM4IO has two of each.

When choosing a Pi solution; what's needed or desired, and what isn't, will play its part as well as pricing.

The Pi 400 is more expensive than the equivalent Pi 4B but cheaper than the equivalent CM4+CM4IO. If the Pi 400 board were sold as a bare board with a reduced price the difference with Pi 4B would decrease and with CM4+CM4IO would increase.

[MikeDB]

Considering just board functionality, based on Foundation suggested retail pricing, using a CM4 Lite board supporting SD Card rather than eMMC coupled with a CM4IO board, the costs for equivalents break down as below -

Code: Select all

.-------.--------. .-------.--------.--------.
| Wi-Fi | Memory | | Pi 4B | CM4+IO | Pi 400 |
|-------|--------| |-------|--------|--------|
|       |  1 GB  | |  $35  |  $65   |        |
|  Yes  |  2 GB  | |  $35  |  $70   |        |
|       |  4 GB  | |  $55  |  $85   |  $70   |
|       |  8 GB  | |  $75  |  $110  |        |
|-------|--------| |-------|--------|--------|
|       |  1 GB  | |       |  $60   |        |
|  No   |  2 GB  | |       |  $65   |        |
|       |  4 GB  | |       |  $80   |        |
|       |  8 GB  | |       |  $105  |        |
`-------^--------' `-------^--------^--------'

Of course, none are exact equivalents.

What this misses is the cost of short cables from the Pi4 to the back panel, and the connector for it. For one of my products I spend £30 a product on these things :
https://uk.rs-online.com/web/p/usb-connectors/9160221/

I don't think the Pi400 will save this in my case, but for others it might

[tweak42]

I would love to see a mechanical keyboard with a Pi 400 built in thus selling the Pi 400 board bare would help facilitate momentum toward that goal.

[aBUGSworstnightmare]

Considering just board functionality, based on Foundation suggested retail pricing, using a CM4 Lite board supporting SD Card rather than eMMC coupled with a CM4IO board, the costs for equivalents break down as below -

Code: Select all

.-------.--------. .-------.--------.--------.
| Wi-Fi | Memory | | Pi 4B | CM4+IO | Pi 400 |
|-------|--------| |-------|--------|--------|
|       |  1 GB  | |  $35  |  $65   |        |
|  Yes  |  2 GB  | |  $35  |  $70   |        |
|       |  4 GB  | |  $55  |  $85   |  $70   |
|       |  8 GB  | |  $75  |  $110  |        |
|-------|--------| |-------|--------|--------|
|       |  1 GB  | |       |  $60   |        |
|  No   |  2 GB  | |       |  $65   |        |
|       |  4 GB  | |       |  $80   |        |
|       |  8 GB  | |       |  $105  |        |
`-------^--------' `-------^--------^--------'

Of course, none are exact equivalents.

Only the 4B has a composite video and analogue audio output connector.

Only the CM4+CM4IO has full-size HDMI sockets, PCIe connector, supports an external Wi-Fi antenna, has a fan connector, and an on-board RTC. It only has two USB 2.0 sockets, a header for two more, doesn't provide USB 3.0 sockets. It uses a 12V barrel connector for power rather than 5V USB-C.

The Pi 4B and CM4+CM4IO supports PoE while the Pi 400 does not.

The Pi 400 with its large heatsink is rated at 1.8 GHZ operation, the Pi 4B and CM4+CM4IO at 1.5 GHz.

All three have differing connector and 40-way header placement. The CM4+CM4IO and Pi 400 have all their primary connectors along one edge, are larger boards than the Pi 4B. Only the Pi 400 is able to disconnect the 5V supply to the 40-way header. It is also the only one which doesn't allow back-powering through that header. The Pi 400 doesn't have CSI or DSI connectors. The CM4+CM4IO has two of each.

When choosing a Pi solution; what's needed or desired, and what isn't, will play its part as well as pricing.

The Pi 400 is more expensive than the equivalent Pi 4B but cheaper than the equivalent CM4+CM4IO. If the Pi 400 board were sold as a bare board with a reduced price the difference with Pi 4B would decrease and with CM4+CM4IO would increase.

sorry, but that's a milkmaid ("Milchmädchen") calculation! Your niether taking the keyboard nor the plastic parts into account in your 'comparison chart', so that'scomparing apples with pears!

A 4GB Pi4 is 55USD and a Keyboard is 17USD. The Pi 4 case is 5USD --> 77USD for the equivalent while it's only 70USD for the Pi400.

[aBUGSworstnightmare]

I tend to agree on this. There's lots of projects where being able to mount a Pi directly in the back of a 1U 19" rack mount unit with the sockets facing backwards without adapter PCBs or cables would be most useful.

Please consider it once the initial rush on Pi400s has died down.

but some of these, let's call them more professional use cases' would benfit fom a DSI connector which is non existent on the Pi400

[aBUGSworstnightmare]

It would be very nice if the Pi400 bare PCB was available for sale separately.
This size and shape would make it ideal for many new projects.

It's slim but has all the ports, making it perfect for DIY Pi laptops, tablets, maybe even clusters. (if the CM4 isn't your style)

paulhothersall agrees.

please sell just the board as a SKU, perhaps with stick on heat sinks.

Its a pi with all IO on one side. this is a huge win for many many projects. I can already see me getting a bunch of these, especially with the higher clocked CPU helps, and it will be eWaste just to toss the keyboard for them.

sorry, but please allow the question how to make a small tablet or laptop when there's no DSI interface available? Your HDMi is on the edge and your A/D board (the interface board to your display) will be inside ... So nice loop wire which can be used as carry handle...

[fruitoftheloom]

It would be very nice if the Pi400 bare PCB was available for sale separately.
This size and shape would make it ideal for many new projects.

It's slim but has all the ports, making it perfect for DIY Pi laptops, tablets, maybe even clusters. (if the CM4 isn't your style)

paulhothersall agrees.

please sell just the board as a SKU, perhaps with stick on heat sinks.

Its a pi with all IO on one side. this is a huge win for many many projects. I can already see me getting a bunch of these, especially with the higher clocked CPU helps, and it will be eWaste just to toss the keyboard for them.

sorry, but pleas allow the question how to make a small tablet or laptop when there's no DSI interface available? Your HDMi is on the edge and your A/D board (the interface board to your display) will be inside ... So nice loop wire which can be used as carry handle...

I was under the impression that these days ports on each side was normal for *Laptop* style devices.

[MikeDB]

I tend to agree on this. There's lots of projects where being able to mount a Pi directly in the back of a 1U 19" rack mount unit with the sockets facing backwards without adapter PCBs or cables would be most useful.

Please consider it once the initial rush on Pi400s has died down.

but some of these, let's call them more professional use cases' would benfit fom a DSI connector which is non existent on the Pi400

I've been doing OEM design on and off for almost 50 years and have never used a DSI connector. Most products in my field use SPI to communicate with LEDs, LCD displays and keys. That said I agreed above that the Pi400 wouldn't fit my use case but I am sure it will for some. Anyway James has agreed they will look at the business case for this later. It's not as though anybody will be affected negatively by them releasing the board as a standalone.

[aBUGSworstnightmare]

I tend to agree on this. There's lots of projects where being able to mount a Pi directly in the back of a 1U 19" rack mount unit with the sockets facing backwards without adapter PCBs or cables would be most useful.

Please consider it once the initial rush on Pi400s has died down.

but some of these, let's call them more professional use cases' would benfit fom a DSI connector which is non existent on the Pi400

I've been doing OEM design on and off for almost 50 years and have never used a DSI connector. Most products in my field use SPI to communicate with LEDs, LCD displays and keys. That said I agreed above that the Pi400 wouldn't fit my use case but I am sure it will for some. Anyway James has agreed they will look at the business case for this later. It's not as though anybody will be affected negatively by them releasing the board as a standalone.

but even in case of connecting something to the GPIO one would loose the benefit of having all connectors on one end. Shure, one can have different level on the rear chassis

[hippy]

What this misses is the cost of short cables from the Pi4 to the back panel, and the connector for it.

Indeed. Trying to put a Pi 4B in a box with all connectors exposed on one side will involve cables. And there may be costs when using other than a Pi 4B. This is just "the cost of getting the base board to use"; that's the best I can do.

People will need to adjust final costs depending on their use case. What cables are needed and the cost of those cables will depend on the use case.

sorry, but that's a milkmaid ("Milchmädchen") calculation! Your niether taking the keyboard nor the plastic parts into account in your 'comparison chart', so that'scomparing apples with pears!

I am only comparing what the costs of getting a bare board would be, because this thread is discussing producing a Pi 400 board separately for use in projects, when I prsume they would otherwise be using a bare board Pi 4B or CM4+CM4IO. Those wanting to use a Pi 400 board currently have to buy the whole Pi 400 and discard the keyboard and plastic.

Some other comparisons, such as creating a Pi 400 equivalent from Pi 4B or CM4+CM4IO would indeed have different costs, would look different.

I'm entirely happy for others to produce their own cost comparisons for fulfilling various use cases.

[MikeDB]

I am only comparing what the costs of getting a bare board would be, because this thread is discussing producing a Pi 400 board separately for use in projects, when I prsume they would otherwise be using a bare board Pi 4B or CM4+CM4IO. Those wanting to use a Pi 400 board currently have to buy the whole Pi 400 and discard the keyboard and plastic.

What is the connector between the keyboard and the Pi400 mainboard anyway ?

Sounds like there's going to be a lot of them going free. Maybe give them to schools as spares.

[gordon77]

26 way FPC ?

[jamesh]

Worth considering that we spent a CONSIDERABLE amount of time and money getting the SD card slot plastics right. It's a very critical part of the design, and difficult to get right, with extremely fine tolerances. Bear that in mind when saying how much easier is will be to put in a case!

[Botspot]

Worth considering that we spent a CONSIDERABLE amount of time and money getting the SD card slot plastics right. It's a very critical part of the design, and difficult to get right, with extremely fine tolerances. Bear that in mind when saying how much easier is will be to put in a case!

Speaking of that, does the sd card "click" in and out? Or is it a press-fit socket?

[aBUGSworstnightmare]

Worth considering that we spent a CONSIDERABLE amount of time and money getting the SD card slot plastics right. It's a very critical part of the design, and difficult to get right, with extremely fine tolerances. Bear that in mind when saying how much easier is will be to put in a case!

Speaking of that, does the sd card "click" in and out? Or is it a press-fit socket?

push-push socket

[cspan]

While it would be nice to have the Pi 400 motherboard sold separately so you could bring your own keyboard, you wouldn't want it without the heat-sink solution they devised, and that heat sink is notably keyboard size/shape.

From what I can find online, the Flirc case does quite well for the Pi 4B, but the Pi 400 does even better, and at higher GHz as well. It's really the best passive cooling for the Pi yet devised.

[hippy]

Worth considering that we spent a CONSIDERABLE amount of time and money getting the SD card slot plastics right. It's a very critical part of the design, and difficult to get right, with extremely fine tolerances. Bear that in mind when saying how much easier is will be to put in a case!

My solution for exposing a Pi's card socket was to cut a larger hole than I needed, position the Pi board, then move 'plastic planks' on the inside in from the left and right, then top and bottom, until I was happy with what I created.

It did take some time but I ended up with a slot which does work, forces the card to slip into the socket and not into the case. It is countersunk enough to stop it being accidentally hit.

That was a Pi with a pull to remove socket rather than push to eject so more tricky to remove the card but the bevelling achieved allows me to get my fingernail under it and I don't remove it that often anyway.

I don't have a Pi 400, don't know how much sticks out and what doesn't, what would be the best approach there, but I imagine people will figure it out. A big hole and "£@$#& it!" when it does get pushed into the case which then needs to be opened will probably do for most home and non-commercial users.

If someone has bought a Pi 400 and re-cased the board; they should be able to cut the SD Card plastic out and glue that in place on their own case. I'd be inclined to use the whole back plastic strip so it becomes mostly a large hole cutting exercise.

An alternative is to cut the edges away so the plastic becomes an L-shaped mounting tray, base and back panel. It then just has to poke through a suitably sized hole.

If it's out of sight it doesn't matter how icky it looks.

[Botspot]

While it would be nice to have the Pi 400 motherboard sold separately so you could bring your own keyboard, you wouldn't want it without the heat-sink solution they devised, and that heat sink is notably keyboard size/shape.

From what I can find online, the Flirc case does quite well for the Pi 4B, but the Pi 400 does even better, and at higher GHz as well. It's really the best passive cooling for the Pi yet devised.

No, asking the Foundation to include the passive heatsink along with the board is a bad idea.

• First, that metal plate is much larger than the circuit board. It's meant to provide structure to the whole keyboard.
• Second, there are already plenty of cooling methods that would work perfectly fine. If there's any airflow available, a conventional finned heatsink will work perfectly fine. Or even a fan.
• Third, if cooling your Pi400 motherboard really was an issue, just underclock it!