wrobell
Posts: 15
Joined: Fri Sep 06, 2013 9:47 am

compute module, the embeddable device

Wed Aug 13, 2014 8:43 pm

Hi,

There is plenty of ideas how to deploy Compute Module, be it better Raspberry Pi networking device, multimedia hub or multi-processor server, but for me it brings hope that to get Raspberry Pi more embeddable.

As a baseline, let's take the following three projects

- ODROID-W - small factor board based on BCM2835, Raspberry Pi compatible outputs, RTC clock and built-in rechargable battery support
- Pi in The Sky project (http://www.pi-in-the-sky.com/) - the project is releasing a board to be used with Raspberry Pi having efficient power regulator and battery voltage monitoring
- MicroPython (http://micropython.org) - easy to program board based on STM32F405 (Cortex M4), which uses its own Python 3 port, small factor, gives hope for quite good run-time on a battery, RTC built-in, IO pins: 5 USARTs, 2SPIs, 2 I2C busses, 14 ADC pins, 2 DAC pins, and 4 servo ports with power

If designing IO board for Compute Module what would you do better than abdeove projects? Things to consider

- form factor
- battery support
- IO pins (GPIO, I2C, SPI...)
- RTC clock
- communication over Bluetooth LE
- sleep mode
- power efficient data storage

Did I miss any other projects, which would influence your design? Any other ideas/things to consider?

riklaunim
Posts: 265
Joined: Tue Apr 22, 2014 7:34 pm

Re: compute module, the embeddable device

Wed Aug 13, 2014 9:35 pm

Hard to tell if there is a point for yet another "prototyping" baseboard for the RPI COM. If you want something very "embeddable" then quite likely it has to be custom or small in a very specific way. And the market of end-users/hackers is rather saturated with Raspberries, so it would be hard to sell amount of boards you would have to order ;)

If I could use only microcontroller then I would use something like PyMCU, MicroPython pyboard etc. (if avoiding C/C++ in Arduino and mbed). If I would need a small embedded PC I would check if average RK3188 Android dongle can be used - either with Android or with Linux (quad core with 2 GB of RAM at Raspberry price... ;)) + microcontroller on USB/Bluetooth if needed. If not then some single board computer for hackers if at all. Sometimes 2G/3G cheap Android tablets are handy (they have GPS, Bluetooth 4, can do simple WiFi hotspots from 3G, battery, display and much more).

wrobell
Posts: 15
Joined: Fri Sep 06, 2013 9:47 am

Re: compute module, the embeddable device

Wed Aug 13, 2014 10:13 pm

riklaunim wrote:Hard to tell if there is a point for yet another "prototyping" baseboard for the RPI COM. If you want something very "embeddable" then quite likely it has to be custom or small in a very specific way. And the market of end-users/hackers is rather saturated with Raspberries, so it would be hard to sell amount of boards you would have to order ;)

If I could use only microcontroller then I would use something like PyMCU, MicroPython pyboard etc. (if avoiding C/C++ in Arduino and mbed). If I would need a small embedded PC I would check if average RK3188 Android dongle can be used - either with Android or with Linux (quad core with 2 GB of RAM at Raspberry price... ;)) + microcontroller on USB/Bluetooth if needed. If not then some single board computer for hackers if at all. Sometimes 2G/3G cheap Android tablets are handy (they have GPS, Bluetooth 4, can do simple WiFi hotspots from 3G, battery, display and much more).
Thanks for the response, but I am afraid you miss the point a bit bringing the discussion to some kind of multimedia devices, which I am really trying to avoid. :)

The existing Raspberry Pi are simply too big and have non-essential components like HDMI, USB support, which do affect form factor and battery usage.

The many MCU boards, while some very interesting, are quite limiting in terms of reusing existing software and software development itself.

Finally, the Android dongles (and especially the one you mention) are overkill for many applications, are as big as existing Raspberry Pi boards and are 3 times as expensive. And why to limit your programming options and suffer with Android? ;)

riklaunim
Posts: 265
Joined: Tue Apr 22, 2014 7:34 pm

Re: compute module, the embeddable device

Wed Aug 13, 2014 10:27 pm

RK3188 dongles now cost as much as Raspberry Pi ver B, and they can run Linux. Smallest versions are smaller than Pi ;) Tablets also get very cheap now - while being a complete device on which you can build other devices and services. RPi and other single board computers (like for example Radxa Rock wit the same RK3188 as dongles) aren't as cool now as they used to be.

Microcontroller will always use less power than a processor, so dumping USB and alike won't save much. And if you dump peripherals you will end up with GPIO only, so in the end a microcontroller would do just fine and no point for Pi. USB allows for WiFi, Bluetooth or webcams, RFID/BarCode etc. readers to be used. HDMI allows to use a display, which sometimes is required. So I don't see any gains of outdoing Odroid-W by limiting features of a board.

wrobell
Posts: 15
Joined: Fri Sep 06, 2013 9:47 am

Re: compute module, the embeddable device

Thu Aug 14, 2014 7:04 am

riklaunim, I am really aware of the options you are mentioning and obviously for many projects a microcontroller would be the best option, but there is a class of projects, where Raspberry Pi (and other, similar boards) is very good fit. Also, please, do not divert this discussion into talk about alternative multimedia devices (be it RK3188 devices or tablets, multimedia feature creep is really off-topic in this thread).

It does not seem like ODROID-W is the ultimate board, simple "cannot be better" is really unconvincing, so having the option of Raspberry Pi Compute Module, what components to put on CM IO board, so it is better for projects requiring features I have mentioned in my first post in this thread?

fruitoftheloom
Posts: 21330
Joined: Tue Mar 25, 2014 12:40 pm
Location: Delightful Dorset

Re: compute module, the embeddable device

Thu Aug 14, 2014 8:01 am

wrobell wrote:riklaunim, I am really aware of the options you are mentioning and obviously for many projects a microcontroller would be the best option, but there is a class of projects, where Raspberry Pi (and other, similar boards) is very good fit. Also, please, do not divert this discussion into talk about alternative multimedia devices (be it RK3188 devices or tablets, multimedia feature creep is really off-topic in this thread).

It does not seem like ODROID-W is the ultimate board, simple "cannot be better" is really unconvincing, so having the option of Raspberry Pi Compute Module, what components to put on CM IO board, so it is better for projects requiring features I have mentioned in my first post in this thread?
I have read this thread several times and can not see any purpose to it, it seems to be a "daydreaming" thread.

Do you intend to manufacturer a range of products ?

Have you purchased a CM Development Kit ?

Or is this a thinly disguised I want a better Pi version whatever thread ?
Retired disgracefully.....
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Ravenous
Posts: 1956
Joined: Fri Feb 24, 2012 1:01 pm
Location: UK

Re: compute module, the embeddable device

Thu Aug 14, 2014 8:14 am

wrobell wrote:If designing IO board for Compute Module what would you do better than above projects? Things to consider
<list...>
"Better" - I suppose the CM could be on a holder board with just GPIO connections, including I2C, serial for a terminal connection, etc. But you would really just be building an Odroid copy. I don't understand what you are asking for and that may be why people aren't giving the answers you want.

I would want battery support, or at least an efficient buck voltage regulator on the board. I wouldn't want a RTC though. I might have audio outputs that are just soldered, without a bulky connector. This would give a pretty small board. But I don't really think it would be very different from the Odroid, etc.

Are you gathering opinions for a project you want to design?

wrobell
Posts: 15
Joined: Fri Sep 06, 2013 9:47 am

Re: compute module, the embeddable device

Thu Aug 14, 2014 8:21 am

fruitoftheloom wrote: Do you intend to manufacturer a range of products ?
No, I wonder if I can squeeze more juice from BCM2835 thanks to CM in my own hobby projects.
fruitoftheloom wrote: Have you purchased a CM Development Kit ?
Yes, but how does it help to answer my questions? :)
fruitoftheloom wrote: Or is this a thinly disguised I want a better Pi version whatever thread ?
No, it is not. I understand my original post leaves room for interpretation, but I believe it frames the discussion, as well. However, if you need more specifics, do not hesitate to ask.

fruitoftheloom
Posts: 21330
Joined: Tue Mar 25, 2014 12:40 pm
Location: Delightful Dorset

Re: compute module, the embeddable device

Thu Aug 14, 2014 8:38 am

wrobell wrote:No, I wonder if I can squeeze more juice from BCM2835 thanks to CM in my own hobby projects
The SoC and PoP Memory are the same for CM and B+, the CM eMMC likely has slightly faster I/O, and 900Mhz overclock seems stable.

It really comes down to the Operating System choice and writing un-bloated code so the CPU can work more efficiently when processing I/O.

Bottom line if you go for an off-the-shelf solution it will come with a one-size-fits-all scenario
Retired disgracefully.....
This at present is my daily "computer" https://www.asus.com/us/Chrome-Devices/Chromebit-CS10/

wrobell
Posts: 15
Joined: Fri Sep 06, 2013 9:47 am

Re: compute module, the embeddable device

Thu Aug 14, 2014 2:53 pm

Ravenous wrote: I would want battery support, or at least an efficient buck voltage regulator on the board.
OK, so we have something in common. Would you be able to be bit more specific and name such voltage regulator? What would be its advantages over the one used in ODROID-W or in Pi in The Sky project?

Ravenous
Posts: 1956
Joined: Fri Feb 24, 2012 1:01 pm
Location: UK

Re: compute module, the embeddable device

Thu Aug 14, 2014 4:50 pm

Don't pay too much attention to my comment, as I already have Model As and the extra bulk of the connectors doesn't trouble me.

I was just suggesting that some beginners will want to build a compact device but will still need a 5V regulator if they're using a battery. Of course those building something with a 5V supply handy won't need this...

I suppose the question is - how compact do you think your board should be? This should determine what you add, I suppose.

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