hpr-knowledge-base/hpr_transcripts/hpr0967.txt

Episode: 967
Title: HPR0967: Raspberry Pi spec review
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr0967/hpr0967.mp3
Transcribed: 2025-10-08 05:44:37

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Music
Hello everybody, my name is Ken Fallon and this is another episode of Hacker Public Radio.
Today I've kidnapped my colleague, Tla Shan, who was last on the network talking about
skating.
Did that ever go ahead?
No, never went ahead.
What happened?
Yeah, the ice wasn't thickened up, so let's focus on technical tricks again.
Another 15 years to age, I think?
I don't know, very sad and depressed.
Anyway, today I wanted to talk about the Raspberry Pi.
We had some discussions yesterday over a cup of coffee about what it is, so for people
who don't know, some guys who work at Broadcom decided to put together a small PC device
based on an ARM processor that would be used in the educational field as a way to get
kids interested again in computers and back to the old days of the BBC's if people had
them and that sort of thing.
Now what was interesting for the Hacker community, of course, is that the prices of these
things are aimed $25 for a one model and for the other model, whopping $35.
So for the price of even one of the lowest-end tablets, you could get 10 of these little
devices.
Now here we have Clashan, who's a hacking, harder hacking enthusiast, I guess.
First of all, Clashan, let's give us a brief history of what you did for your school
project, for instance.
Yes, I programmed in my free time, I programmed a lot of micro-processors with the C code,
normally micro-chip, Atmel, that are the most common low-end devices I programmed, so
they're low speed, 8 megahertz up to 60 megahertz running devices, very close to hardware
specific things, not really close to software specific things like the Raspberry, so that
there's more cancer expertise, the unique part of that one.
So yeah, I think it's nice to talk a little bit about low-end capabilities of the device,
I think the rest you can all find on the internet.
I just wanted to say that this thing will run Ubuntu or Debian or a native Linux version,
but a lot I wanted to get here was Clashan, we're going to go through the specs from the Wikipedia
page and just maybe give you an idea more on the hacking side, what's possible.
Yes, I think I don't know how it works a little bit with the drivers, but probably we need to
shoot the board at self, how it works with the drivers, how to address the low level
for the low level part of the board, but yeah, we're going to talk a little bit about the general
purpose interface, the UART interface, the IAS squared C bus, the SBI bus, that are the two low
level of the low level, okay, but before we go to that, as far as I know, the way that they're
going to drive those is using the proc file system, so you write ones or not proc file system
the written drivers, and you just write ones and zeros to file, so to be easy to program that
in any language Python, so you're even bash programming. I think that counts for the general purpose
IO, okay, let's start. And I think for the series, series report, I think it's the same way you
will do within a normal operating system. What do you think of the ARM processor itself?
It's a 700 megahertz. Yes, I think it's a very fast ARM processor if you compare it with a normal
up-mill low-cost CPUs, like the $2 CPUs, where you can only do low level communication with it,
and now Ethernet is applicable, so I think it's very good choice, it's very fast.
GPU? Yeah, it's a separate video core. Yeah, so I'm not really familiar with that one, so
you're able to do H264 1080p, so I think it's just a very interesting board to see when it comes out.
Video wise, but we're also not going to focus on that. No, yeah, it's going to be 128
make of RAM in model A, and then the model B is going to be 256 shared with the GPU.
It's going to be two USB, one USB port in model A and two in the USB via an integrated USB hub.
Yes, and that's I think a nice, what you see with laptops and with templates and with the computers,
they don't have low level easy way to communicate to the outside world. You always need a serial
port, or a USB port, or an Ethernet port to communicate to a low level design, like a motor,
like a button, an LED, a dimmer, a lighting dimmer, et cetera, et cetera. And this board,
already, by default, has some low level capabilities, like the eight times general purpose IO.
So, okay, let's go down to that. We have, of course, the video compasses HDMI,
and we have audio jack. We've got onboard storage STMMC slot, and on the model 2U, the 10100
Ethernet card. Now, what's a GPIO all? I think it's a general purpose IO interface. I think this
board operates at a voltage of a 3.3 volt. So, theoretically, on the output of a GPIO, you can
solder to a connector, an LED, for example, a small LED, not a power LED, and then you can control
it by the software, as you described earlier, with this turn it on and off. So, that's a very
use. Of course, if you want to switch a lightning build in your house, for example, like 60 watts,
of course, you cannot attach it directly to the IO of the board. You need some, and you can do a
mechanical transformer in between, like a relay, so you can add a little bit of the driver. So,
it's very easy to integrate this almost computer directly with an external hardware.
So, it will be a relatively simple thing to have, send a voltage out on this
general purpose IO board, which would switch a switch, and that switch would switch the real switch.
Yes, that's a little bit... So, that's nice, I see it has 8. So, you can do some...
So, you can limit the LED, because you can also take an input circuit.
Yeah, it's an IO board. You can configure it as an input or as an output,
so for a combination of one and eight. So, like, you could then wire up a sensor to your windows
of your house, for instance, and switch on your alarm, etc. or display it on the screen,
or publish it on your web server, running on your Unix machine, saying that the window is open.
So, this is kind of nice features. Of course, the eight general purpose IO is not very
a lot. It's nice for playing around, it's nice for troubleshooting, it's nice to make
a flashing light or blinking light. So, you're saying don't buy this card. I say buy it
definitely, because there's a lot of more possibility. So, if you want to extend it for bigger
project, you can make use of the... For example, it has an IA square C bus, that's a bus,
I think original designed by Philips, and it is a bus designed to communicate between
integrated circuits on the board itself. It's very nice bus, it's a two wire bus.
It's not designed for a long-distance communication, but you can buy a very small microchip,
I think it's a couple of dollars, to do an IO expander. So, with an IO expander, you can just have
eight IOs. So, if you buy six of these small integrated circuits, you're soldering on a PCB,
you connect it to the IA square C bus on your board, and you have another 64 IO in an output,
configurable. I like that. And what sort of price range would they normally be? I mean,
that's obviously more complicated. Yes, the hacking now. Yeah, the IA square C bus is very common.
You can buy a temperature sensor that you can indicate on IA square C bus as well.
The only bad thing to plug this on the internet side, you need always have a microchip in between
to publish it to your laptop or per sheet, but this board makes it possible because it has already
this low-level capability default built-in. And that's the advantage of this board. For example,
you could buy one of these extenders, put temperature sensors from back at the house, wind sensors.
Yeah, they will then directly come through these boards and end up on your computer in the
text file, seeing 96 degrees out. Yes, the only bad thing as I indicated, ready, the I
square C bus is not very likely to be used for that one because it's a low-distance communication
protocol. It's more like to read in buttons, et cetera, et cetera. But if you build another board
attached to that, but for example, if you if you look a little bit, it has also a UART on that one,
and I think that's a universal asynchronous receiver and transmitter. We see it in a professional
world still as an RS-232 board. You can buy a small converter that makes it RS-422 or RS-485,
that are all like standardizations on the UART interface, so you can achieve longer distance up to
one kilometer up. So that's very nice. Of course, a UART board you have on a default laptop
and a PC as well, but it's a relatively simple serial port. Yes, it's a serial port. You can
add only one of them, so you don't have the moment. No, but you can buy a USB to serial converter as well
because it has a USB port on there as well. So that's very basic. You can make use of that
combination of this channel purpose IOS as well. So I think then it has another more sophisticated
interface as well, that's called the SPI interface. It's a little bit the same as an
i-scrashy bus, only I'm not really familiar. It's a little bit more complicated bus, and it is
really, really much more faster, and it is used only for also short communication lines.
So that is by default, it's part of the board, so that's very nice and you don't have to
tell them the default laptop or default computer, so that's a big advantage as well. So you definitely
see this as being something a hardware hacker might be interested in. Yes, you can do a lot of
home group project with this board, very simple, very basic, without needing a very expensive PC
with a lot of additional hardware, because the hardware is on top of the board. So the SPI
interface, it's a really faster interface, you can use it for attaching more memory, you can use it
for attaching put sound communication on that one, etc, etc. So it is a lot of nice low-level
general purpose hardware hacking stuff on there, and that you don't see a lot with the default
laptop or default computer, and it's kind of like an Arduino on steroids, I guess. Yes, yeah,
and also it's coming into the same price ranges they are doing, I think. Yeah, it's a little bit
more expensive, but if you buy an Arduino with an Ethernet board, you definitely are maybe even
more expensive than this board. You have a few Arduino's, yeah, I have a few Arduino's with some
Ethernet boards as well, and here it's all in one board. Yeah, so it's very nice, and you can
access it into this, obviously. Yeah, probably, yeah. And the power rating 500 milliamps. Yeah, I
think that's not a lot. You could probably feed them power over Ethernet, so when you're ethernet.
Yes, I think that there's not default, but yeah, it's an else, it's something you need to do. I don't
know if it can take, but probably if you have an off-the-shelf USB, you can power it off the USB
connector itself. Yeah, that would be a very interesting board, and it's quite size. Yes, it's
very nice that I would like to go always for the B-board because it has default Ethernet on
there. Yeah, and yes, Ethernet makes difference. It's like 35 versus 25. Yeah, and according to Wikipedia,
runs Debian and Fedora and Arch Linux, so. Yeah, so I think this board is definitely a benefit to
people that want to play a little bit around with a homebrew electronic projector around the house.
Well, they haven't started taking orders yet, so when they do, we'll keep you in touch, and feel free.
Everybody to send in some tips and tricks on what you've done to hardware hacking in general.
Class out quickly, any projects that you would see in your future?
Yes, some, I think, some home demotica projector, definitely to control the blind,
home automation, to control the blinds, to control the lighting, to control the switching,
and also because it has an advantage of Ethernet web server controlled by an tablet from home,
control the heating systems, etc, etc. Okay, so how would you see that having in each floor
one of these? Yes, I think because it's so cheap, it's really easy to have multiple boards
around the house, because it makes the cabling a lot easier.
It's actually the price of a sensor, really. Yes, the sensor is much more expensive.
Yeah, of course, you need to still buy the high power components like dimmers or relay still, but
I think it's, and how would you go about switching those? Typically, is this something a standard hardware
shelf would have? Yes, you have default dimmers, what are very expensive, sometimes you can
build in yourself, of course. But nowadays, we don't use a lot of dimmers anymore with the LED
lighting, etc. So normal switching would be very simple, achievable with this one.
Cool. Yeah, so I think I would like to see a few of them in action, and a few of them in action,
yes, definitely. I now do a lot of stuff with RD, RD no boards, but they are difficult to
having a simple communication like SSH, Delnet, web server, running website.
You have a lot of already default on this board, so you're already, you've got all the
less sorted, and you can concentrate on your hardware. File system.
Okay, well, I think that covers it for today. Pleasure and thanks very much for taking
the time to record the problem, and tune in tomorrow for another exciting episode of Hacker Public Radio.
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