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Raspberry Pi Model B Schematics

raspberrypi.org

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Re: Raspberry Pi Model B Schematics

#11

Post by stephen_g »

elliotanderson wrote: post #10
chj wrote: post #8

is there anybody specialized in circuit design? i mean, how hard is it to build a cheap Pi equivalent board? If this is so popular, why no commercial version?

The Pi has kicked off some interest in hardware hacking for myself too. My question is how hard would it be to embed an 802.11 radio into the same board for a discreet sensor project

I haven't looked at the schematics yet, but generally a SoC based design like this needs at least a six layer board, which combined with the speeds it runs at is pretty advanced electronic design...

Coupled with that, it can be really hard to get low volumes of some of the parts they use, like the SoC, PMIC (power management IC) and so on (although you can get free samples if you ask sometimes - but they generally won't give them to you unless there's a chance you'll put through a big order with them in the future). And soldering the BGA parts onto the board would be a pain unless you pay for it to be assembled for you...

Unless you know a lot about that sort of thing, it would probably be more successful to design something that interfaces with a Pi.

Re: Raspberry Pi Model B Schematics

#13

Post by beagle3 »

chj wrote: post #8

is there anybody specialized in circuit design? i mean, how hard is it to build a cheap Pi equivalent board? If this is so popular, why no commercial version?

> how hard is it to build a cheap Pi equivalent board?

Cheaper than the RaspberryPi? extremely hard. While a body more experienced than the RaspberryPi with more manufacturing clout can probably do that, the RaspberryPi foundation is a non-profit. Roku/Apple might be able to build a RaspberryPi for 75% the price, but their own profit would make it more expensive.

There are equivalently-or-better specced stuff on the market (Roku boxes that run Linux that can occasionally be found for $50, Apple TV that can occasionally be found for $80). But nothing at the $25/$35 price point with similar specs - and I don't expect any in the near future.

Re: Raspberry Pi Model B Schematics

#14

Post by bigiain »

chj wrote: post #8

is there anybody specialized in circuit design? i mean, how hard is it to build a cheap Pi equivalent board? If this is so popular, why no commercial version?

Cheaper than a "real" Pi? Does $35 even get you an Arduino with an SD card and an ethernet port? _Maybe_ someone'll clone these, but surely these not much "fat" in the price to be undercut the "official" ones by enough to make it worthwhile?

Re: Raspberry Pi Model B Schematics

#15

Post by joezydeco »

lwat wrote: post #9
chj wrote: post #8

is there anybody specialized in circuit design? i mean, how hard is it to build a cheap Pi equivalent board? If this is so popular, why no commercial version?

Make no mistake, clones are on the way. For example this device: http://rhombus-tech.net/allwinner_a10/ is supposedly both cheaper and more powerful than the Pi.

When you say "clone", do you mean pin-equivalent or just another SoC-based board with similar features and performance?

If you're trying to duplicate the RPi exactly, you won't be able to. Nobody else can get the BCM2835 chip except the RPi guys.

Re: Raspberry Pi Model B Schematics

#16

Post by sveiss »

stephen_g wrote: post #11
elliotanderson wrote: post #10

Earlier quoted context omitted.

The Pi has kicked off some interest in hardware hacking for myself too. My question is how hard would it be to embed an 802.11 radio into the same board for a discreet sensor project

I haven't looked at the schematics yet, but generally a SoC based design like this needs at least a six layer board, which combined with the speeds it runs at is pretty advanced electronic design... Coupled with that, it can be really hard to get low volumes of some of the parts they use, like the SoC, PMIC (power management IC) and so on (although you can get free samples if you ask sometimes - but they generally wo…

My university had a wonderful pair of courses in the first year of its CS degree. The first had us build a Z80-based computer on breadboards, with a couple of hulking ancient HP logic analyzers to debug with. For the second, they gave us an assembled Z80 single board computer and had us do something interesting with it -- games displayed on an oscilloscope, control a small robot, etc. For both courses compilers were strictly forbidden.

It was a great way of bridging the abstraction gap between the physical hardware and the code we typed at the keyboard. (We were also required to take courses in basic digital and analogue design and compiler construction to give an overview the rest of the stack, too.)

Nowadays, I think they've switched to using ARM boards for the second course in the build-a-computer series. From a hardware reliability and cost perspective it makes sense, but it's a little sad that the "I built one like this! Just not quite so neatly..." factor has been lost.

As a software guy, the details of the Pi's PCB layout are about as impenetrable to me as the internals of the SoC itself are. It's Magic Electronic Stuff!, but just a tad more powerful than the Z80 I used to play with.

Re: Raspberry Pi Model B Schematics

#17

Post by lwat »

joezydeco wrote: post #15
lwat wrote: post #9

Earlier quoted context omitted.

Make no mistake, clones are on the way. For example this device: http://rhombus-tech.net/allwinner_a10/ is supposedly both cheaper and more powerful than the Pi.

When you say "clone", do you mean pin-equivalent or just another SoC-based board with similar features and performance? If you're trying to duplicate the RPi exactly, you won't be able to. Nobody else can get the BCM2835 chip except the RPi guys.

No this device has a faster CPU, more RAM etc. It's not an exact duplicate of the Pi.

Re: Raspberry Pi Model B Schematics

#18

Post by DanBC »

chj wrote: post #8

is there anybody specialized in circuit design? i mean, how hard is it to build a cheap Pi equivalent board? If this is so popular, why no commercial version?

The foundation didn't think the device would be so popular. They are ramping up production, so that should help with getting products out there.

As for equivalents: It's a 6 layer PCB, with BGA and other SM components. That's really hard to do at home. So you're unlikely to see hobbyist rip-offs anytime soon.

At some point there might be another similar device - mass made in China, more power, more ram, but probably much worse documentation. There's certainly a big market for tiny dirt cheap computers.

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