Simple GPIO testing board


65 posts   Page 2 of 3   1, 2, 3
by domesday » Mon Jun 18, 2012 8:40 pm
Yes the design is fine. Why don't you lay it out on your breadboard and give it a try just to satisfy yourself.
Posts: 258
Joined: Fri Oct 21, 2011 5:53 pm
Location: UK
by RaspberryPiBeginners » Tue Jun 19, 2012 8:21 am
Waiting on parts to arrive:) ordered a big-bag-o-components.
Click here for my unofficial YouTube Channel > http://goo.gl/oFYBD
User avatar
Posts: 214
Joined: Fri May 11, 2012 6:54 am
Location: Soham, Cambridgeshire
by DexOS » Tue Jun 19, 2012 1:51 pm
I have a problem with your video being posted on the main news page of the raspberry pi site.
Its seems knowledge counts for nothing these days, if you can present in a professional way, then what you post must be right.
I see it time and time again, people who can write flowing articles about topics are put on a pedestal.
When in a lot of cases there talent is writing or presenting, not what the topic is about.
This also works the other way around, as people with knowledge on a subject, but who are not the best communicators, are brush a side.

The raspberry pi foundation should at least check that the video its linking too is not going to damage your pi

By the way nicely presented video.
Batteries not included, Some assembly required.
User avatar
Posts: 860
Joined: Wed May 16, 2012 6:32 pm
by RaspberryPiBeginners » Tue Jun 19, 2012 2:22 pm
DexOS wrote:By the way nicely presented video


I don't think I've ever had someone call me stupid in such a polite way before :lol:

You know I do state that people need to proceed at their own risk. Secondly if they follow it to the letter it wont break anything. I've got this advise from other sites, I guess with the electronics side of things I might be the blind leading the blind a little bit, however I tested and it didn't blow up my pi.

The foundation were posting my channel this just happened to be my latest video, the rest of my videos are fine. I've now updated the diagrams to use the 3v3 so in the main much safer now.
Click here for my unofficial YouTube Channel > http://goo.gl/oFYBD
User avatar
Posts: 214
Joined: Fri May 11, 2012 6:54 am
Location: Soham, Cambridgeshire
by sg84 » Tue Jun 19, 2012 2:44 pm
DexOS wrote:Its seems knowledge counts for nothing these days


Seems manners don't count for much either...
Posts: 3
Joined: Tue Jun 19, 2012 2:11 pm
by MattHawkinsUK » Tue Jun 19, 2012 2:49 pm
The diagram on the wiki has been updated so it has the proper GPIO labels on it.

I've now completed a few experiments with LEDs and switches. I always use my own pull up/down and limiting resistors because it is all too easy to make a mistake. For most peoples projects there isn't much to be gained by taking the risk.

The confusion about pin labelling shows that most people will not correctly manage the internal resistors so I think it is safer for people to add external resistors. The information on this level of detail is all over the place and I don't really trust its accuracy. No disrespect to the authors but the wiki doesn't make it clear what pins have internal resistors and how you know if they are enabled or not. So I'm ignoring them.
My Raspberry Pi blog and home of the BerryClip Add-on board : http://www.raspberrypi-spy.co.uk/
Follow me on Google+, Facebook and Twitter (@RPiSpy)
User avatar
Posts: 483
Joined: Tue Jan 10, 2012 8:48 pm
Location: UK
by Gert van Loo » Tue Jun 19, 2012 10:40 pm
MattHawkinsUK wrote:The diagram on the wiki has been updated so it has the proper GPIO labels on it.

I've now completed a few experiments with LEDs and switches. I always use my own pull up/down and limiting resistors because it is all too easy to make a mistake. For most peoples projects there isn't much to be gained by taking the risk.

The confusion about pin labelling shows that most people will not correctly manage the internal resistors so I think it is safer for people to add external resistors. The information on this level of detail is all over the place and I don't really trust its accuracy. No disrespect to the authors but the wiki doesn't make it clear what pins have internal resistors and how you know if they are enabled or not. So I'm ignoring them.


All pins have internal pull-up/pull-down resistors. That is not on the wiki. It is in the data sheet. That data sheet has a list of all GPIO pins with their special function. If you look at that table you also find the pull-up/down status after reset for each pin. I don't blame you for not finding the information. After all there are hundreds of pages with information, but I hink you could have asked for that before making remarks like "The information on this level of detail is all over the place and I don't really trust its accuracy". The information for that level of detail is all where it should be: in the data sheet under the GPIO section.
User avatar
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 2029
Joined: Tue Aug 02, 2011 7:27 am
by DexOS » Wed Jun 20, 2012 1:27 am
sg84 wrote:
DexOS wrote:Its seems knowledge counts for nothing these days


Seems manners don't count for much either...

Manners are for people with too much time on there hands, like people that rejoin a forum just to post the above.
Batteries not included, Some assembly required.
User avatar
Posts: 860
Joined: Wed May 16, 2012 6:32 pm
by abishur » Wed Jun 20, 2012 4:13 am
DexOS wrote:
sg84 wrote:
DexOS wrote:Its seems knowledge counts for nothing these days


Seems manners don't count for much either...

Manners are for people with too much time on there hands, like people that rejoin a forum just to post the above.


No manners are for *everyone* who desires to participate on this forum, and this goes both ways.

I do agree that there is no need to create a new account if you want to say something. Either have the conviction to say it from a single account or just let the comment remain unsaid.

As for the unfounded accusation that Liz is blindly posting Youtube videos based on presentation rather than content, let's take a look at the facts.

Let's assume you actually get a full 5V from the 5V pin (Using my industrial voltmeter I read 5V going into the pi, 4.8V across TP1 and TP2, but only 4.55V across the 5V and ground pin).

So you have a full 5V going into the LED, the red LED will have the lowest voltage drop. For the sake of argument, we'll say it's worst case scenario and you only get a drop of 1.63V.

Once leaving the red LED, we now have a voltage of 3.37V, and just for the heck of things lets say that there's zero voltage loss across the two resistors.

3.37V is a little high and I wouldn't deliberately do it, but even that should be within the safety margins of the chip. More importantly here though is the fact that this is a max "perfect world" scenario where voltage out always equals voltage in with no loss. They're numbers you're just not going to see out of the 5V pin unless you're providing too high a voltage to the pi in general, which is a whole other bag of worms. Anyone following his instructions would have to mess up the wiring to damage it, and when it comes to miswirring things they're just a likely to damage the pi trying to hook up to the 3v3 rail!

Now I'm not saying I agree with using the 5v rail. What I am saying in all this is that I take issue with this accusation that Liz blindly posts content because it's presently nicely. This individual did do a superb job going over the basic software control of the GPIO pins and a decent, brief glance at the hardware interfacing of the pins, but it's not any more likely to destroy your pi than anything involving an amateur messing with the GPIO pins.
Dear forum: Play nice ;-)
User avatar
Forum Moderator
Forum Moderator
Posts: 4250
Joined: Thu Jul 28, 2011 4:10 am
Location: USA
by rurwin » Wed Jun 20, 2012 6:43 am
Our argument was not with the LED circuit, which was always safe, it was with the switch circuit, which in the original fed 5V to the GPIO inputs. And with the practise of using 5V at all, which increases the risk of a random accident breaking the RaspPi.

The way RaspberryPiBeginners has produced the video without any technical details and then put those on a web site, means he could (and did,) edit them after the video was produced. By the time that Liz posted a link to the video, at least the main problems with the circuit had been fixed. Nobody is ever going to produce a video that everyone agrees with, and if they wanted to there would have to be an enormous number of re-takes. By extracting the technical details, RaspberryPiBeginners ensured that he could fix any problems that arose. He is a very good presenter, and is open to criticism; that's the most that one can ask. The most that one could criticise him for is not being 100% correct in his facts before going on camera, and nobody can ever know whether they know enough.
User avatar
Forum Moderator
Forum Moderator
Posts: 2903
Joined: Mon Jan 09, 2012 3:16 pm
by domesday » Wed Jun 20, 2012 8:54 am
I agree, the fact that he came here asking for advice and was willing to take on board suggestions and make corrections is a good thing. We all make mistakes and it is not a question of what mistakes we make but how we deal with them. I'm sure he has learnt a few new things about electronics in the process and will likely ask about anything he is uncertain of before making another video.

It is good that there are people who are enthusiastic enough to spend time sharing what they have discovered with others. If it is something he enjoys then I wish him all the best and hope to see things progress. Just complaining about something is not terribly constructive, if you think there is something wrong either offer constructive advice or if you can do better, show us your masterpiece.
Posts: 258
Joined: Fri Oct 21, 2011 5:53 pm
Location: UK
by sg84 » Wed Jun 20, 2012 10:08 am
abishur wrote:I do agree that there is no need to create a new account if you want to say something. Either have the conviction to say it from a single account or just let the comment remain unsaid.


Agreed - that probably came across as a bad first and only post. Here, have a second post to dilute it's impact by 50% :)

Seriously though, no one that gives their spare time to contribute to a community should be belittled for making a mistake.
Posts: 3
Joined: Tue Jun 19, 2012 2:11 pm
by abishur » Wed Jun 20, 2012 2:38 pm
rurwin wrote:Our argument was not with the LED circuit, which was always safe, it was with the switch circuit, which in the original fed 5V to the GPIO inputs. And with the practise of using 5V at all, which increases the risk of a random accident breaking the RaspPi.


oh :oops:

The way RaspberryPiBeginners has produced the video without any technical details and then put those on a web site, means he could (and did,) edit them after the video was produced. By the time that Liz posted a link to the video, at least the main problems with the circuit had been fixed.


Ah, that would explain why I couldn't find anything wrong in the video or the resources he linked to.
Dear forum: Play nice ;-)
User avatar
Forum Moderator
Forum Moderator
Posts: 4250
Joined: Thu Jul 28, 2011 4:10 am
Location: USA
by Lorian » Wed Jun 20, 2012 3:18 pm
I think there is a case for a beginners board with some leds and a couple of switches and perhaps a DS18S20 and maybe even some buffered pins to a small breakout socket. Not everyone that is going to want to teach programming with the GPIO is going to want to make their own boards or use a breadboard.

I think a small custom circuit is in order, all sat on a female 2x13 header. It could be tiny, epecially if sm leds were used.

Perhaps the foundation might run a competition to see who can design the smallest, cheapest to produce board to do similar. might be fun.
Posts: 112
Joined: Sun Mar 11, 2012 10:09 am
by RaspberryPiBeginners » Wed Jun 20, 2012 3:27 pm
Lorian wrote:I think there is a case for a beginners board with some leds and a couple of switches and perhaps a DS18S20 and maybe even some buffered pins to a small breakout socket. Not everyone that is going to want to teach programming with the GPIO is going to want to make their own boards or use a breadboard.

I think a small custom circuit is in order, all sat on a female 2x13 header. It could be tiny, epecially if sm leds were used.

Perhaps the foundation might run a competition to see who can design the smallest, cheapest to produce board to do similar. might be fun.


Yey back to my original idea. I was hoping to get a few made, 1 or 2 for myself and a few to give away.
Click here for my unofficial YouTube Channel > http://goo.gl/oFYBD
User avatar
Posts: 214
Joined: Fri May 11, 2012 6:54 am
Location: Soham, Cambridgeshire
by Lorian » Wed Jun 20, 2012 8:44 pm
Ah yes, but I had in mind a crowd-sourced design, the best possible, at the lowest unit cost, with an open design that lots of people would want to use. An open standard, rather than something proprietary.
Posts: 112
Joined: Sun Mar 11, 2012 10:09 am
by domesday » Wed Jun 20, 2012 9:43 pm
RaspberryPiBeginners is publishing his design, but it is only a simple board with a couple of LEDs and switches on.

If what you want is small buffer board then there are plans to publish the design for one in the MagPi magazine in a couple of issues time.
Posts: 258
Joined: Fri Oct 21, 2011 5:53 pm
Location: UK
by RaspberryPiBeginners » Thu Jun 21, 2012 8:38 am
domesday wrote:RaspberryPiBeginners is publishing his design, but it is only a simple board with a couple of LEDs and switches on.

If what you want is small buffer board then there are plans to publish the design for one in the MagPi magazine in a couple of issues time.


And i'll buy one.
Click here for my unofficial YouTube Channel > http://goo.gl/oFYBD
User avatar
Posts: 214
Joined: Fri May 11, 2012 6:54 am
Location: Soham, Cambridgeshire
by RaspberryPiBeginners » Fri Jun 22, 2012 8:34 pm
Typical, so I bough a massive bag of electronic components and couldn't find the 2.2k resistors. Would any of these be ok?

2k, 2K7, 2.4K? Thanks in advance

Image
Click here for my unofficial YouTube Channel > http://goo.gl/oFYBD
User avatar
Posts: 214
Joined: Fri May 11, 2012 6:54 am
Location: Soham, Cambridgeshire
by domesday » Fri Jun 22, 2012 9:00 pm
2K will do fine.
Posts: 258
Joined: Fri Oct 21, 2011 5:53 pm
Location: UK
by RaspberryPiBeginners » Fri Jun 22, 2012 11:59 pm
domesday wrote:2K will do fine.

Could i be more confused? I tried it with the 2K resistor and it didn't work, so i swapped the 2k resistor backout for a cable and it worked. ..... :cry: :?:

If you see my picture attached it's basicly the same layout but with and without a resistor.

Image
Click here for my unofficial YouTube Channel > http://goo.gl/oFYBD
User avatar
Posts: 214
Joined: Fri May 11, 2012 6:54 am
Location: Soham, Cambridgeshire
by domesday » Sat Jun 23, 2012 12:09 am
Are you sure those pull-down resistors are 10K ?
Last edited by domesday on Sat Jun 23, 2012 12:13 am, edited 2 times in total.
Posts: 258
Joined: Fri Oct 21, 2011 5:53 pm
Location: UK
by RaspberryPiBeginners » Sat Jun 23, 2012 12:11 am
domesday wrote:Are you sure those pull-down resistors are 10K ?


.............no lol. Big bag-o-electroics......big-bag-o-crap :roll:

#feelingstupid
Click here for my unofficial YouTube Channel > http://goo.gl/oFYBD
User avatar
Posts: 214
Joined: Fri May 11, 2012 6:54 am
Location: Soham, Cambridgeshire
by domesday » Sat Jun 23, 2012 12:13 am
They should be Brown, Black, Black, Red, they look like Brown, Black, Black, Black to me 100 Ω.
Posts: 258
Joined: Fri Oct 21, 2011 5:53 pm
Location: UK
by RaspberryPiBeginners » Sat Jun 23, 2012 12:36 am
domesday wrote:They should be Brown, Black, Black, Red, they look like Brown, Black, Black, Black to me 100 Ω.


HHmmm, I gave the lad at Maplin a list when I bought those R1 resisters. Looks like i need http://goo.gl/5255W app on my android phone to check that they are giving me. F*****g Maplin's.
The list had "2 x 10k resistor"

Image
Click here for my unofficial YouTube Channel > http://goo.gl/oFYBD
User avatar
Posts: 214
Joined: Fri May 11, 2012 6:54 am
Location: Soham, Cambridgeshire