Simple matrix of Raspberry Pi components?

stalled.

Too big. Even the nominal 7" display is uncomfortably large. I'll look for a 3rd party display that wil fit in pocket comfortably.

I those I've seen as they use Android.

I definitely have a minority POV ;}

Reply to
Richard Owlett
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Go visit Adafruit:

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They've got a lot of stuff for the RPi, and sell a 3.5" touch screen for just under $US 40.00 -

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Martin    | martin at 
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Reply to
Martin Gregorie

I like this one

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A bit fragile around the edges so you will need a case (they don't have one) if you want to make the whole thing portable.

Reply to
A. Dumas

The equivalent of a PDA of decades past using current production and avoiding smartphones(sic) &/or Android. I was introduced to computers in early 60 as an E.E. student. Though I don't have many C.S. credits, I have done work related coding in 8080/8085 assembler and dBaseII (so I'm dated ;) Most of my tech work was as engineering support or 3rd party inspection. Once when working thru a temp-perm firm I got a interview because the client just had meet someone who could document my strange resume.

I just found

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and
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Data sheet at

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Just brewed a mug of coffee. Time to drool over data sheet ;}!

Reply to
Richard Owlett

On Sat, 15 Feb 2020 09:21:14 -0600, Richard Owlett declaimed the following:

By the time you've fit a case, battery, and display on this thing, it isn't going to fit anything smaller than a "cargo pocket" on a pair of pants, or a large coat pocket.

An R-Pi 3B+, no battery, no display, but in a case, takes up 3.75 x

2.625 x 1.125 inches -- and that is with sharp corners to the case.

My ancient HP PDA with a double-thick extended battery is 4.625 x 3 x

1.125 (regular battery makes it only 0.75 thick) -- and never did fit in pockets for me; I carried it in a zipper closure leather case which also held 3x5 business cards and spare stylus. Oh, and it has smoothly rounded edges to reduce wear in whatever pockets one places it.

Much of the thickness comes from the USB and Ethernet ports. If you rip off those, and the GPIO expansion header, the rest of the R-Pi 3B+ (without case) is less than 0.5 inches (much of that being the HDMI and audio jack).

You'll need to rig a low-voltage shutdown trigger to safely shut it off when the battery goes low, to avoid corrupting the file system. Linux does not like having the power dropped on R/W file systems. My PDA was good for about three days of usage with standby with the thick battery -- and that was with a reported PXA27x Intel xScale core running at a sluggish 624MHz.

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	Wulfraed                 Dennis Lee Bieber         AF6VN 
	wlfraed@ix.netcom.com    http://wlfraed.microdiversity.freeddns.org/
Reply to
Dennis Lee Bieber

My second project isn't dissimilar to yours- its a replacement for a Medion PNA (i.e. built-in GPS, 3.5" touch screen, WinCE). Both the Pimoroni 4" screen that A Dumas suggests and the Adafruit 3.5" screen would do my job, and probably yours too. The Pimoroni has much the best resolution (800 x 480) compared with the Adafruit (480 x 320).

All RaspberryPi use Repbian, a port of Debian Linux, by default though there are other OSen available.

I don't know how much Android has diverged since Linux was forked to create it or what command shell or desktop manager it uses.

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Martin    | martin at 
Gregorie  | gregorie dot org
Reply to
Martin Gregorie

It looks too small unless the accept touch of a stylus rather than a finger. For one of my potential uses I was considering displaying a pseudo-QWERTY layout for inputting alpha-numerics. Link to specs?

That's one it's advantages. My laptops run Debian.

Reply to
Richard Owlett

The Medion I'll need to replace sooner or later has a 3.5" diagonal screen inside a wide bezel, so is 4.5" diagonal across the case. Its screen, being consumer-grade WinCE, is probably 480 x 320.

I'll be running a port of the same WinCE program, LK8000, on the RPi: its developers have already ported it to Linux. So, I think its safe to say that the screen features would be the same size on the Adafruit screen and a little bigger on the Pimoroni screen. Since I can use LK8000 without problems on the Medion, it should be fine on an RPi too.

Fair enough.

As to size: If necessary, I can make my own case from epoxy-board. All I care about is that its overall size can be no bigger in height and width than the Medion (4.1" x 3.125") or it will start to hide other instruments on the panel. I think I can manage that even if I use the Pimoroni screen. Here's the Medion in its usual place:

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Lastly, I don't mind how thick the thing is because it will be screwed to a flexi-mount that supports it in front of my panel and anyway it will be running off the glider's main batteries via a 12v->5v converter. Even so, I may end up using a Pi Zero, simply because I'll need both power and GPS signal in and USB data out so I can to download the log after a flight. If I use a Pi Zero I can minimise connections: a D-9 for power and GPS data in and a micro-USB or wifi for log data out.

However, you should definitely take note of Dennis's comment about bulk, and consider whether you'd be better using a Pi Zero, or one of the small Arduinos, rather than a bigger and much thicker Pi with its bank of ethernet and USB B sockets on one end. The Pi Zero is 65mm x 30mm x 5-8mm. It's thickness is not given on the drawings, but a case sold for it is only 15 mm thick overall.

You might be able to get a Pi Zero plus a 4" screen and a battery into a case that's a bit thinner than a bare Pi 2,3 or 4, but that would certainly depend on the shape and size of the battery.

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Martin    | martin at 
Gregorie  | gregorie dot org
Reply to
Martin Gregorie

On Sat, 15 Feb 2020 20:38:00 -0000 (UTC), Martin Gregorie declaimed the following:

Problem with the Arduino route (I considered mentioning them but refrained) is that they don't run a formal OS in which programs are loaded from a file system. The versions using an ARM Cortex-M processor (Due, for example) can usually support FreeRTOS if one needs interrupt handling or multiple threads of execution, but they still expect to boot directly to /the/ application which runs from flash memory -- RAM is basically a very large "register set" only used for variable storage during execution. The Cortex-A of R-Pi and BeagleBone Black both use flash for a file system and load programs into RAM for execution

The Due is 84MHz Cortex M3 (no floating point), 512kB flash, 96kB RAM (in banks of 64 and 32kB).

A TIVA TM4C123G LaunchPad (since the specs are on the box I have available -- the Due specs I have to Google) is an 80MHz Cortex M4F (32-bit with hardware floating point), 256kB flash, 32kB SRAM, 2kB EEPROM. One thing it is unusual in is that it has way too many timers (6 64-bit, which can be split into 12 32-bit, AND 6 32-bit which can split into 12 16-bit ). But it is cheap (presuming TI still makes them -- about $13).

The larger TM4C1294 is 120MHz M4F, 1MB flash, 256kB SRAM, 6kB EEPROM, only 8 32-bit timers, but has Ethernet connector [your application will need to include a TCP/IP stack to use it].

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	Wulfraed                 Dennis Lee Bieber         AF6VN 
	wlfraed@ix.netcom.com    http://wlfraed.microdiversity.freeddns.org/
Reply to
Dennis Lee Bieber

On a sunny day (Sat, 15 Feb 2020 07:38:22 -0600) it happened Richard Owlett wrote in :

I agree, I do not like android at all (tried programming some app once) some of those phones can be rooted and run Linux though.

From the other perspective there is the Linux / MS windows based 'pipo':

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no experience with that myself but people tell me it works for them. could make sort of a 'desktop PDA'.

Reply to
Jan Panteltje

96kB RAM

EEPROM,

My Mistake - I thought the Beaglebone Black ran Linux. The Pi Zero looks like flavour of the day for a more sylph-like case.

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Martin    | martin at 
Gregorie  | gregorie dot org
Reply to
Martin Gregorie

AIUI there are a number of devices that can be re-flashed with Linux, such as the Nexus LG 5 (not that I would recommend the Nexus 5 due to hardware problems)

e.g. Ubuntu Touch, hence presumably Debian based like the RPi.

I'm not suggesting you should take this path, as I don't know your requirements, or even the problems you have with Android. I'm just say a path exists.

We are all a minority wrt some things ;o) If at least half this group wasn't mildly "on the spectrum" I would be surprised.

Reply to
Pancho

Yes. *BUT* manufactures of Android devices do everything possible to prevent that (starting with voiding of warranty).

I'm one of those that believe Google has unethically asserted that Android is FOSS.

Count me in ;}!

Reply to
Richard Owlett

On Sun, 16 Feb 2020 11:50:37 -0000 (UTC), Martin Gregorie declaimed the following:

Beagles are not Arduinos. Most common Arduinos use an 8-bit AVR processor, the higher end models have ARM Cortex M3, or M0 processors.

The BeagleBone Black does run Debian -- it has a Cortex A series processor (A series => Application processors, M series => Microcontroller processors).

It also has a pair of 200MHz PRU microcontrollers -- originally meant for coding custom I/O protocols as they have a fixed/known instruction timing.

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	Wulfraed                 Dennis Lee Bieber         AF6VN 
	wlfraed@ix.netcom.com    http://wlfraed.microdiversity.freeddns.org/
Reply to
Dennis Lee Bieber

The references I was given did not make it make simple to select mutually compatible components -- the required information being scattered among multiple tables or URLs.

I propose to create a single spreadsheet {likely distributed in the TAB delimited variation of a CSV file}.

I have two specific questions: 1. Has this been done before? 2. Is there an already existing site that would accept it? {Their submission requirement could affect my layout.} {I'm still working on column headings that would balance coverage and simplicity ;}

Reply to
Richard Owlett

On a sunny day (Mon, 17 Feb 2020 08:21:14 -0600) it happened Richard Owlett wrote in :

Just for the record what you say makes no sense whatsoever for me Your OP was to connect a touch display to a raspi

This has been done

There are a zillion types of displays and all can [by the cunning] be interfaced to a raspi. To do that you need to

1) know electronics design (interface [logic]levels, interface types, interface speed, both for GPIO and the display unit. 2) know programming in a close to hardware language to write the driver, and the user program, interface protocols i2c, SPI, maybe USB and HDMI.

When /if you use the search engines and ask for a display for raspberry there are plenty around

or use ebay:

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take the first hit:

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Seems there is a free driver for it (come to think of it I do have a display like that somewhere I think ;-) ) I do not like small displays end even less 'touch screens', good keyboard and typing speed is essential for programming or even writing these texts.

And that programming you WILL have to do sooner or later...

I will leave it at his.

You say EE 1960, well then it was much the same... I did my exams in those years, no puters yet, Electronics is a never stopping learning thing /experience.. I never stopped, Somebody starting from scratch these days would make me wonder :-) :-) There is a newsgroup sci.electroncs.design if you are into hardware design, maybe there is still activity there.

And then what should the PDA do? Are you gonna write that or write your own? Usually all I need is 'wcalc' and 'units' and a few more Unix utilities, there is also a windows emulator and LTspice for electronics simulation that runs on that (never use it much myself). How far does 'PDA' reach? Do you have an oscilloscope? test equipment? All that here and without that I would not venture into raspi interfacing unless it was a ready to plug in solution display. ... intergalactic connection broken earthling lost

Reply to
Jan Panteltje

*NO* *NO* *NO* *NO* *NO* *NO*

My original subject line was "Simple matrix of Raspberry Pi components". As majority of replies were *Off Topic* I modified the subject line and clarified my goals with *TWO* sentences and asked *TWO* questions.

Reply to
Richard Owlett

Android is FOSS. You don't need to install Google's apps and play store for the OS to run and be usable.

You've not said, or I missed it, what this gizmo will do. But to me, I'd not fanny about with touch displays and such tat, I'd use the phone I carry anyway to handle the UI. Run the software on the Pi and use a web framework to handle the IO. Software is written in whatever language you want for the Pi with the phone's browser and maybe some client side scripting in JS on the phone with the connection via Wifi. Modern phones have nice displays that you can read in daylight, decent resolution and a touch input.

YMMV

Reply to
mm0fmf

No, but you do usually need binary drivers and/or firmware to run it on most platforms.

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Steve O'Hara-Smith                          |   Directable Mirror Arrays 
C:\>WIN                                     | A better way to focus the sun 
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Reply to
Ahem A Rivet's Shot

In general terms (I've not looked much at screens) Raspberry Pi compatible devices (calling them components seems a little confusing to me, as that would imply the parts on the rPi board itself) connect directly to the Pi rather than to each other. So it's a question simply of what interfaces the Pi has, and what devices connect to those interfaces.

I don't think so. If so, I'd imagine it would only cover devices that connect to the GPIO header (Pi HATs are the standardised form). There's also the camera connector, I don't know what connects to that besides cameras and adapters relating to them.

If you include the industry-standard interfaces like USB, HDMI, and Composite video, then obviously the sky's the limit. Every TV manufactured since they started putting Composite video inputs on them would have to be included, for example.

There's a wiki with extensive documentation relating to the Pi here:

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However even if the scope of your "compatibility matrix" was limited just to GPIO devices (so as to be vaguely achieveable), it would be borderline unmaintainable given the number of boards that come and go all the time. Plus it would probably get too long to be easily read/filtered. You'd really want some sort of database back-end and a moderated public submissions/editing system. With a good web interface that could be quite handy, so long as people do actually maintain it.

If you're just looking to document compatible devices that _you_ are interested in, then I'd suggest it would be better published on a personal site, if at all, because it will probably not be helpful for most other people.

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Reply to
Computer Nerd Kev

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