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The Piface my thoughts

Former Member

Its amazing how you read about something that you are sure will solve the problem you are having only to find out , that it could and would only theres no way of using it because of a complete lack of knowledge sharing in the community. Or is it that like me , an ordinary person without a phD in electronics who just gets sick of trawling the internet for simple non existent tutorials on how to use it, and gets so fed up he takes the thing back and gets a refund ? I have built simple robots with Arduino modules in the past using the online tutorials and lots of community help. I’ve even given back with the meager knowledge I have obtained. But the Piface ? Its  great on paper and looks snazzy , but really how do the developers expect new to the product people like me to even stick with it when theres not even a simple motor wiring tutorial. A couple of ..oh look I got a fan to wiz around.. but where's the wiring tutorial? I wanted to do everything from the raspi all in one box robot and I thought I had that with the PiFace, but I was wrong. Yes before you start posting pdf this, and blog that, I’ve been over them 10 times, zoomed into photos gone through OCR’s classroom challenge until the photos are so small you can see what's happening, installed wiring looked at the schematics. If you search for Pi tutorials there looks like a lot , but its actually only a few that have been copied and plagiarized by other sites looking for click traffic, and some people (youtube) who want to show off what they can do with it but have no intention of passing on the knowledge. Wheres the guys who designed it? I don't want to be carried or baby sat through this I just want a point where I can achieve getting one motor to go forward and reverse. With arduino I did that in in less than 10 mins , the piface I have tried for the last 3 days without success, I have probably blown the thing up anyway.The designers and manufacturers should be ashamed of themselves, bigging up this module so mugs like me buy it and then leaving them without any worthwhile help.The Piface website is a sham , “oh look what it can do.. industries flock to see the new module !!” Any help on there to set it up ? None ! I’m glad I kept the receipt for the raspi and Piface, they will be going back for a refund.

  • Hi David,

     

    I agree to an extent that it cannot be easy if you're new to this, and the fact that it was a university project means that the Piface Digital site doesn't look as friendly or easy to use as it ought to be. And the fact that you tried to self-learn is good, it shows that you were not the type of person to ask without doing research.

     

    As far as I can tell, if you need bidirectional motor control with the PiFace, it uses relays for that, or it would require additional circuitry. I'm not 100% sure though, so maybe others may be able to advise.

     

    The best place to look for a getting started guide is actually on the e14 site, here rather than the university site.

     

    It's probably too late for you if you are returning them, but assuming you still wish to control a motor bidirectionally, there are two ways (regardless of any device you use to interface):

    1. Use a motor driver board (it would need to connect directly to the RPI or to the PiFace). Motors have some unique requirements (since they are high-power, inductive loads), which microprocessors are incompatible with, so it usually entails a driver board

    2. Use the two SPDT relays on the PiFace to control a single motor - a bit wasteful if your motor is not high power, so let me know if this is what you still want to do, and I can draw the wiring (in summary the motor would connect to the COM pin on the two relays), with the 'N.O.' and 'N.C.' pins going to a power source.

  • in reply to shabaz

    Thanks Shabaz , I will go back to the Arduino and work from there. Maybe I will revist the idea in a year or two when the makers have got their act together and maybe they might release a product with some support. Its a bit like Nvidia releasing a new video card without drivers. In all honesty its a joke. I hope someone who is thinking about buying a PiFace might read this thread and go down another route much more supported route.

  • in reply to Former Member

    Hi David,

     

    For the Arduino, this board would work nicely with any small DC motor up to 10V (so it covers popular motor voltages like 3V, 6V, etc) and is low cost. It would also work with the RPI (no need for the PiFace in this case, although it would protect the RPI in case of some miswiring).

    The Arduino is a good (ideal) choice for many control applications, I've used the microcontrollers on the Arduino (Atmel devices) for quite a while, I think they are great.. The RPI could be useful for when you want to connect your circuit to the Internet (the Arduino can do this, but often it's not appropriate for that purpose) or need the horsepower for some particular purpose; but it requires some Linux experience that the Arduino doesn't need of course.

  • 1 person willing to help ! shows my point .. sorry this is a case in point and please correct me if Im wrong, but the piface is just a money making product that exists of the back of the raspi?

  • in reply to Former Member

    Actually I believe the outage is a very helpful tool for amateurs starting out on the raspberry pi especially given thy a lot of people using it will be no more than 12 so this is very useful and it has a very good proggraming interface to help

  • in reply to Former Member

    Prompted by David's original comments I had  a quick look at the PiFace support both on the web in general and on Farnell. I have to agree that the quality of (easily locatable) documentation is truly dreadful, especially considering the target market. The operating instructions on the Farnell product page look to be about the best (I didn't test them out of course) but I didn't find a schematic in my short time of looking. Pretty much every micro or FPGA manufacturers' dev boards yield a schematic after a couple of clicks.

     

    Manchester Uni really need to get their act together on this  - it's meant to be for teaching so the least I would expect is a schematic, a comprehensive description of how it works and a few complete applications examples with circuits, wiring diagrams (for the inexperienced) and proper explanations.

     

    None of this seems to be available and that seems to be par for the course with RPi in general - all talk.

     

    I think David has made the right decision re the Arduino which is a great deal more learner friendly.

     

    MK

  • in reply to michaelkellett

    Hi Michael,

     

    I tried hard too but had to give up trying to find a schematic on an official site, and google would only find it on sites where it was unclear where people got a copy of it from, or if it was the latest. The uni blog did have a couple of links to a file called rpbreakoutV0_4_sch.pdf but the links didn't work.

    Maybe these changes need to be done:

     

    1. On the product page, replace the 'Technical Data Sheet' (one page) with a PDF that is combined with that single page and the 'Operating Instructions' which is more useful and has circuits and example code.

    2. Have a link to this Piface Digital site on the product page. If the two PDFs above cannot be combined, then the product page should just direct to that site.

    3. Have a copy of the actual schematic on that site too if not also on the product page

    4. e-mail Manchester Uni and let them know that their http://pi.cs.man.ac.uk/interface.htm site needs this information on the first page.

     

    Does this seem reasonable, or any other ideas? Perhaps we can just paste this into the feedback location on this site once we're done refining the list of  changes that are needed.

     

    EDIT: I agree on the RPI comments too. It looks like the official RPI site is very text-rich, whereas it needs to have a capability for people to post thorough projects, documents and schematics. In the site forum (assuming that is the place people go for RPI detail), most of the information is text, with very little photos, diagrams, files, tables, i.e. some of the basic things (from a site point of view) needed to allow complete projects or tutorials to be well documented. Otherwise, beginners may have to trawl through many people's website home pages (which may or may not have commenting), with no idea if what they are following is good practise or not (guessing).

  • in reply to Former Member

    I have no problem with the programing side and I think your are missing the point.. program what ? Make an LCD blink.. whoopee I can no go to my maker knowing I can make an LCD blink .. But wire a motor to it, wheres the documentaion ? Wheres the wireing plans , wheres the schematic.. infact to some it up .. where is the help ? If you bought a microwave oven  and it came with no instructions or any online help would you be happy ? Or in the Piface case, it tells you what it you can use it for but not actually how to use it or even where to start.