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Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 12:39 pm
by Geometrixeng
Hey Everybody,

I want to purchase a Raspberry Pi to do some basic image capture and color analysis. So I basically want to capture a bitmap image and then look at specific predetermined areas of the bitmap and analyze the colors in only those areas. I want to determine the RGB values of those colors and then compare them with a color chart. I may also want to read a barcode or QR code. I am an "okay" programmer with C/C++....but definitely not my core expertise.

I think that I am going to install Ubuntu. And then I will use OpenCV and ROS for image capture and analysis.

So what do you recommend for Raspberry Pi??? 3B? 2B?...etc. WiFi would probably be a good thing to have, so this puts me into the 3B. Should this be my only criteria? Or is there another Raspberry Pi that is better suited for my application?

TIA,
--Neal

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 12:50 pm
by LTolledo
Welcome to the forums!

A Raspberry Pi 3 Model B + perhaps....

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 1:11 pm
by jahboater
Geometrixeng wrote:
Wed Sep 19, 2018 12:39 pm
I think that I am going to install Ubuntu. And then I will use OpenCV and ROS for image capture and analysis.
Do try Raspbian as well - its the "official" OS for the Pi and is well optimized and well supported here.
https://www.raspberrypi.org/downloads/raspbian/
Geometrixeng wrote:
Wed Sep 19, 2018 12:39 pm
WiFi would probably be a good thing to have, so this puts me into the 3B. Should this be my only criteria? Or is there another Raspberry Pi that is better suited for my application?
Yes, the 3B+
Forget the old 3B. The new model is the same price and is far superior.
As for WiFi, the 3B+ does 5GHz as well, and has a better antenna.

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 1:39 pm
by W. H. Heydt
Pretty much the basic advice for buying your first Pi...get the current top model. At the moment, that is the Pi3B+. Once you're familiar with the Pi and have a project with special requirements, then--and only then--consider other models.

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 2:46 pm
by jbudd
If you get a Pi 3B+, keep it in a case and be very careful when you connect things to the GPIO pins.
You might consider putting some nail varnish or other insulating lacquer over the metal cover of the Wifi chip too (the one with the raspberry logo).
A lot have people have lost their 3B+ to an accidental short circuit there.

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 3:17 pm
by DirkS
jbudd wrote:
Wed Sep 19, 2018 2:46 pm
A lot have people have lost their 3B+ to an accidental short circuit there.
Can't remember hearing that before. Can you substantiate that (link to some info source or so)?
And how many is 'a lot'? 10s 100s, 1000s? Or even more?

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 3:25 pm
by Brandon92
jbudd wrote:
Wed Sep 19, 2018 2:46 pm
If you get a Pi 3B+, keep it in a case and be very careful when you connect things to the GPIO pins.
Or if you "don't" know what you are doing, or you don't thrust yourself. A better option is to disconnect the power before you connect anything to the GPIO connector.

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 3:49 pm
by Heater
Make yourself happy:

Get a Pi3B+. Best performance and other goodies so far.

Put Raspbian on it. Best support so far.

Do not divert from this course unless you really have a reason to.

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 4:52 pm
by jbudd
A lot have people have lost their 3B+ to an accidental short circuit there.

Can't remember hearing that before. Can you substantiate that (link to some info source or so)?
And how many is 'a lot'? 10s 100s, 1000s? Or even more?
I have no idea how many 3B+ Pis have died with the red LED on but no activity and the power management chip the only one that feels warm. 100% of the one I bought died like that.
Since the 3B+ came out it seems fairly common to see someone asking in the forum why their Pi isn't working and the answers point to a short circuit. So it's somewhere between vanishingly rare and infrequent.

Nor is it clear that a short circuit between the 5V GPIO pin and the cover over the wifi chip is the only cause.
I think I have seen one of the forum moderators say that's the cause in 99% of cases.
I did not notice myself making a short circuit, I thought the Pi was running, I shut it down, when I tried to start it it was dead. But it was not in a case and I had been attaching/detaching a Hat device so a short circuit could have occurred.

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 5:28 pm
by hippy
jbudd wrote:
Wed Sep 19, 2018 4:52 pm
A lot have people have lost their 3B+ to an accidental short circuit there.

Can't remember hearing that before. Can you substantiate that (link to some info source or so)?
And how many is 'a lot'? 10s 100s, 1000s? Or even more?
I have no idea how many 3B+ Pis have died with the red LED on but no activity and the power management chip the only one that feels warm.
Quite a few.

I have counted about 40 posts from members who have had 'Red LED but no Activity LED syndrome' and seemingly for no good reason. These are 'was working, isn't now, I didn't do anything untoward' cases which don't seem down to people shorting things out or not knowing what they were doing.

Unfortunately I haven't counted cases where people have had their 3B+ die because they have shorted things out and the Pi then won't work, appears to exhibit the same symptoms. I can recall what feels like maybe a dozen or so cases but wouldn't like to put a figure on it.

It does seem to me that shorting things out on a Pi 3B+ is more terminal than for previous Pi versions, and is more prone to just stopping working anyway. But I have always acknowledged that the number is probably small in comparison to the number sold.

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 5:42 pm
by bensimmo
Shorting out is by and by, as mentioned no evidence. Could just be a 'people say it's that'
----
How do you short the 5V gpio easily in that many numbers to the WiFi case, sounds like a load of bollocks to me.
----
Either way it's irrelevant to this question.
Might as well say buy a laptop and a USB camera just to be safe ;-)

-------

Anyway back to the question.
Buy a 3B+ and a ZeroW.

Build it on the 3B+, then see if it'll run on the ZeroW.
You'll need a different cable for the camera on the ZeroW.

But if it runs fast enough, you'll have a compact design and save power.

If not, then you'll have to think of another project to use the Zero with :-)
Win, win ?

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 5:49 pm
by fbe
If you insist on Ubuntu, the old Raspberry Pi3B is currently the better choice, as the downloadable Ubuntu Mate 16.04 images for Raspberry Pi don't run on a Raspberry Pi3B+ and a beginner should start with a system that works out of the box.

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 5:54 pm
by DirkS
hippy wrote:
Wed Sep 19, 2018 5:28 pm
Quite a few.
Don't know if you noticed but @jjbudd was actually saying
jbudd wrote: You might consider putting some nail varnish or other insulating lacquer over the metal cover of the Wifi chip too (the one with the raspberry logo).
A lot have people have lost their 3B+ to an accidental short circuit there.
That's what I responded to...

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 5:56 pm
by hippy
bensimmo wrote:
Wed Sep 19, 2018 5:42 pm
Shorting out is by and by, as mentioned no evidence. Could just be a 'people say it's that'
To a degree. There are those who come here and report they did do something silly, admit they did short things out, or quite possibly did, and are then seeing the No Activity LED problem with the Pi 3B+ so there seems a reasonable correlation there.

Then there are those who report their Pi has died but are adamant they didn't short anything out; 'was working, rebooted, and it didn't'. While it's sometimes suggested the SD Card had not been formatted or they shorted things out, that doesn't appear to have been the case.
bensimmo wrote:
Wed Sep 19, 2018 5:42 pm
Either way it's irrelevant to this question.
I disagree. It makes me reluctant to recommend buying a Pi 3B+ to anyone even though the Pi 3B+ is the superior product on other measures.

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 6:37 pm
by HawaiianPi
fbe wrote:
Wed Sep 19, 2018 5:49 pm
If you insist on Ubuntu, the old Raspberry Pi3B is currently the better choice, as the downloadable Ubuntu Mate 16.04 images for Raspberry Pi don't run on a Raspberry Pi3B+ and a beginner should start with a system that works out of the box.
This ^

My first recommendation would be to get a 3B+ and use Raspbian, but if you have a strong preference for Ubuntu, then get the older Raspberry Pi 3B instead and save yourself some headaches. FYI: Raspbian is based on Debian Linux, which is also the base for Ubuntu, so the two operate very similarly (if you are familiar with Ubuntu you should feel right at home with Raspbian).

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 6:51 pm
by Brandon92
hippy wrote:
Wed Sep 19, 2018 5:56 pm
Then there are those who report their Pi has died but are adamant they didn't short anything out; 'was working, rebooted, and it didn't'. While it's sometimes suggested the SD Card had not been formatted or they shorted things out, that doesn't appear to have been the case.
Indeed, why blaming yourself, if you can blame someone else. And they will not believe you often also.

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 7:03 pm
by jbudd
hippy wrote: ↑
Wed Sep 19, 2018 5:56 pm
Then there are those who report their Pi has died but are adamant they didn't short anything out; 'was working, rebooted, and it didn't'. While it's sometimes suggested the SD Card had not been formatted or they shorted things out, that doesn't appear to have been the case.

Indeed, why blaming yourself, if you can blame someone else. And they will not believe you often also.
I thought that my Pi was working; shutdown and sometime later wouldn't reboot. I also thought it was possible I shorted it out. Thanks to your clearer vision I now realise that it was indeed entirely my own fault.

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 7:18 pm
by Brandon92
jbudd wrote:
Wed Sep 19, 2018 7:03 pm
hippy wrote: ↑
Wed Sep 19, 2018 5:56 pm
Then there are those who report their Pi has died but are adamant they didn't short anything out; 'was working, rebooted, and it didn't'. While it's sometimes suggested the SD Card had not been formatted or they shorted things out, that doesn't appear to have been the case.

Indeed, why blaming yourself, if you can blame someone else. And they will not believe you often also.
I thought that my Pi was working; shutdown and sometime later wouldn't reboot. I also thought it was possible I shorted it out. Thanks to your clearer vision I now realise that it was indeed entirely my own fault.
You have to take my answer with a grain of salt ;)
Some people don't what to say/write that they made a mistake. But this is of course not always true.

Re: Which Raspberry Pi Should I Buy

Posted: Wed Sep 19, 2018 8:48 pm
by Heater
Nah, the 3B+ is as tough as nails.

I'm sure that if there were a problem with it's delicacy it would be all over then net by now. Like the problems with the PoE hat have been.

Well, that is not the case.

Re: Which Raspberry Pi Should I Buy

Posted: Thu Sep 20, 2018 2:32 pm
by hippy
Heater wrote:
Wed Sep 19, 2018 8:48 pm
Nah, the 3B+ is as tough as nails.
That does not appear to be the case from what members have reported here.

The evidence does seem to me to point towards the Pi 3B+ being more likely to suffer terminal failure than previous Pi variants did for the same adverse events, and also more prone to random and terminal failures.
Heater wrote:
Wed Sep 19, 2018 8:48 pm
I'm sure that if there were a problem with it's delicacy it would be all over then net by now. Like the problems with the PoE hat have been.

Well, that is not the case.
I don't think that it being 'all over the net' or not is ever the correct measure of whether there is a problem or not. It frequently seems to me there can be millions of mentions of things perceived to be a problem when they really aren't, yet often few mentions of things which are.

Issues often exist under the radar until they reach critical mass or the issue is admitted to and then the floodgates open. One wouldn't have thought there were a looming migration issue in Europe despite all the warnings of that. It was only when migrants started kicking down borders it got any real coverage. Same too with vaginal mesh implants, sexual abuse, and many other things.

Is the Pi 3B+ overly delicate, a problem variant ? I don't know and it perhaps depends how one chooses to quantify it. All I know is I would not want to be one of the 40 or so members who have reported their Pi 3B+ 'just died' on them for no obvious reason.

Re: Which Raspberry Pi Should I Buy

Posted: Thu Sep 20, 2018 3:29 pm
by jamesh
What was the figure quoted above ? 40 issues?

Out of approximately 2 million 3B+ sold. Yes, that many.

Not only that but some of those issues caused by people shorting out the Pi whilst powered up. So user error.

The 3B+ is not overly delicate, unless you count a 0.002% failure rate as overly delicate.

If you are one of those 0.002%, then you will feel agrieved. But you are also damn unlucky.


As for the OP's question, the Pi3B+ running Raspbian is the best option.

Re: Which Raspberry Pi Should I Buy

Posted: Thu Sep 20, 2018 3:47 pm
by jbudd
The 3B+ is not overly delicate, unless you count a 0.002% failure rate as overly delicate.
Isn't it a bit disingenuous to imply that out of 2 million sold only 40 have succumbed in this way?
I think 40 was an estimate of the number of people who have posted about it in the forum.

I'm sure the Raspberry Pi Foundation has done tests.
What proportion of RPI3B+ tested survived a deliberate short circuit from Pin 1 (3.3V) to the Wifi cover?
What about Pin 2 (5V)?

Will the Raspberry Pi 4 have the same exposed metal cover, or has the design been tweeked to obviate even this tiny risk of damage?

No, I don't feel aggrieved. I think it's interesting that an enhancement in the design had unexpected consequences.
I'm disappointed by the official response though. It's reminiscent of larger purveyors of computers and operating systems.

Re: Which Raspberry Pi Should I Buy

Posted: Thu Sep 20, 2018 4:06 pm
by hippy
jamesh wrote:
Thu Sep 20, 2018 3:29 pm
Not only that but some of those issues caused by people shorting out the Pi whilst powered up. So user error.
That 40ish was those I had counted who insist there was no user error. I excluded those who had done something which could explain the failure or where they may have been doing something wrong.

I don't know what the full number of unexplained failures is but all along I have been saying it probably is a small number of reported failures against the number sold, just 1 in 50,000 or so, but that's cold comfort to those it has happened to.

The good news is that reports of unexplained failures seem to not have appeared for the last couple of weeks so perhaps it was just a batch problem.

Re: Which Raspberry Pi Should I Buy

Posted: Thu Sep 20, 2018 6:00 pm
by Heater
hippy,

I do agree that my "all over the net" statement is a bit vague and unmeasurable. On the other hand when there are problems with products people tend to write about it in blogs and twitter posts or whatever now a days.

Call me crazy but I think when we are discussing failure modes and failure rates of electronic gadgets talk of immigration into Europe and vaginal mesh issues is totally irrelevant.
Is the Pi 3B+ overly delicate, a problem variant ? I don't know and it perhaps depends how one chooses to quantify it. All I know is I would not want to be one of the 40 or so members who have reported their Pi 3B+ 'just died' on them for no obvious reason.
Exactly. Given that you don't know, why are you strongly suggesting there are problems?

Yes it's shitty for those 40 or so people coming here with a problem. That is a very small number.

Re: Which Raspberry Pi Should I Buy

Posted: Thu Sep 20, 2018 7:56 pm
by chwe
jamesh wrote:
Thu Sep 20, 2018 3:29 pm
What was the figure quoted above ? 40 issues?

Out of approximately 2 million 3B+ sold. Yes, that many.

Not only that but some of those issues caused by people shorting out the Pi whilst powered up. So user error.

The 3B+ is not overly delicate, unless you count a 0.002% failure rate as overly delicate.

If you are one of those 0.002%, then you will feel agrieved. But you are also damn unlucky.


As for the OP's question, the Pi3B+ running Raspbian is the best option.
well that's statistics for cheaters... as probably 90% of all statistics you'll find :lol: :lol:
assuming the 40 are correct.. that's actually only the fraction of pi users showing here up to complain that their board doesn't work anymore.. you can't use "sold boards" as denominator in this calculation.. You might use the warranty returns of your distributors but I'm quite sure that's a business secret.. :P