So Many Things to Do Video

Please note – this blog is WELL out of date and all of my blog items and much, much more have now been moved to http://tech.scargill.net

I’ve been meaning to update the blog – and I just keep getting sidetracked with the many interesting possibilities of Node-Red….  so – I put a short video together here. Should be something of interest in it.

https://www.youtube.com/watch?v=xoQ_Fs31xtM

Pete

Node-Red on The Raspberry Pi

Raspberry Rip

When the Raspberry Pi came out I had one on order straight away. This was the future, so they said. It turned up several months later – rubbish operating system, almost no library material out there.

Remember this? this is straight from the website today..tmpF063 There it is, less than 20 quid for a computer.. Sounds sensible – gives even Arduino a run for it’s money, right?

Well, that’s the theory – but a quick trip even to Amazon website in the UK reveals something different..

tmp5ACA

Sorry, what…… £40?? You could buy a cheap TABLET from China for that – and include the screen for heaven’s sake?

Perhaps if and when there is a proper environment for it and the price actually drops (no doubt importing from China) then it may be time to look again, until then…

The Mighty 1284p

The 1284p is the next step up from the ATMega328 chip powering many of the “Arduino” type microcontroller boards and their many clones.

Why another chip? Well, anyone who has used the ATMega328 knows that it’s a great controller chip but the lack of RAM soon gets very tiring. Also if you’re messing with things like Ethernet and maybe you want a Real Time Clock, perhaps access toSD memory, the libraries have a habit of filling your FLASH memory much faster than you’d like.

1284p chipWhy the 1284p? That’s simple – there are only so many of these chips in DIP format – that is the old 0.1” pin format that is easy to use for prototyping – the other upgraded chips are surface mount and a PAIN to solder.

The 328 chip has 32Kbytes of FLASH (for your programs), 1K of EPROM (for storing data permanently) and 2K of RAM (for variables). The likes of the Ethernet code EATS up the RAM in no time. Finally, it’s also quite easy to run out of Interrupts and port bits.

Don’t get me wrong, the 328 is a great general purpose chip but it has it’s limits. A  problem with many other chips is the cost – by the time you’ve finished you may as well have bought a Raspberry Pi and the idea surely is to keep costs low.

Well, the 328 can be as cheap as a couple of pounds or so… and the 1284p can be had for double that. What do you get for your money?

  • 128K Flash (ie 4 times as much)
  • 16K RAM (ie 8 times as much – MOST welcome)
  • 4K EEPROM(4 times as much)
  • 32 pins as against 23
  • 3 interrupts as against 2
  • 8 analog ports as against 6
  • 2 UARTS as against 1

As you can see in the diagram above, putting together a prototype board is a snap (provided you have a TTL-USB converter which I use for all my kits.)

Here is the information you need. If you’re starting from scratch you need the Arduino IDE, the TTL to USB converter (for programming) and a few bits and pieces for your prototype – information for that is all here.

tmp4AFFFollow instructions and you get this on your IDE bottom right when you’ve set the right board..

The standard BLINK test which flashes a LED once a second, when modified to use output 16 – will flash physical pin 22 on and off as per my photo demo above.

Thanks here to Aidan Ruff for pointing me in the right direction and supplying the test chip – which will soon end up in some long-abandoned project (because I ran out of room in the ‘328). Magic.

AT LAST–the Raspberry Pi in person

Raspberry PiI arrived home this evening from a couple of days meetings to find this small package. I’ve put my hand there to give you a sense of scale.

Raspberry PiWithin the package was a little box and a load of regulatory compliance timewasting stuff from Farnell (about which I could give 2 hoots frankly).

Inside of the box was a metalized package – and inside of the metalized package… the LONG-AWAITED Raspberry Pi!

I’ll let the pictures speak for themselves. The unit plugs into a USB connector – and perhaps a TV and network cable – and that, presumably is where the real magic is supposed to start.

Raspberry Pi

That’s the easy bit over, the rest has not been quite so satisfying up to now.  Anyone used to the likes of the Arduino knows you simply plug the chip into your PC, run up the IDE, select an example program and hey presto, the rest is up to your imagination – just the thing for getting kids interested – instant gratification followed by a learning curve as simple or complex as you want to make it. Was the Raspberry Pi going to be the same?

Erm, no. You can’t run this board off the Micro-USB cable – it needs too much power- so plug it into a suitable adaptor, plug it into your TV or monitor, plug in a keyboard and mouse and…

Now it starts to get more amateurish. Assuming like MOST people you have a PC, you have to go off and get the free program WINDISKIMAGER and the DEBIAN img file (lost already?). You need an SD card to hold the image file. On my second attempt I managed to get an image file onto the SD card. Plug that into the underside of the Raspberry Pi, plug in the power and…

Whew. Lots and lots of horrible Linux-fanatic text including gripes that it could not find a real-time clock… and a retry. After 3 or 3 retries the (text) prompt came up (oh, and my second USB keyboard and mouse – the board seems a little choosy which ones it likes). I put in user name “pi” and password “raspberry (no, none of this comes with the board, you have to go looking)… and up came an old “dos prompt”. I types in the relevant command and HEY PRESTO, graphical interface. Turns out the RTC was not necessary as it gets the time from the Internet – so WHY land the beginner with all that crap?

Still – impressive stuff, a graphical interface – for under £30…

tmp482E

Well, yes, but – there is only one web browser in the Debian installation – and it does not support Flash (this is a FAR, FAR cry from Ubuntu, no, really – a different PLANET to Ubuntu 12)… no big deal  – so I powered up the browser.. this took some patience-  and then punched in the FSB website.

Raspberry Pi

The site has been extensively tested with the major browsers, various Internet Explorers, Firefox, Chrome, Safari on PCs, Macs and iPads – even on the iPhone and Android phones… conclusion – the browser that comes with Debian is CRAP… not only that it took nearly 2 minutes to display the page.

I’m going to give this the benefit of the doubt – and assume I’m using a very, very slow SD card and pass no more comment until I have another to test. If this is the best the unit can do, heaven help the kids who’ll be stuck trying to do something with it – especially a generation used to fast PCs.

The information out there looks… patchy to say the least, perhaps after all it’s as well I didn’t get this in February..

More as I find out more.

Raspberry Pi for You, Sir?

Wheeeeeeeeeeeeee. AT LAST… I was beginning to doubt this would ever happen. I an almost smell the excitement I felt when my first Sinclair Mk14 was on it’s way (mind you most of that smell was components overheating).

As predicted, most people by now will have forgotten what the hell a Raspberry Pi is – after all the initial excitement back in February… so a reminder…. a sub-£30 computer board complete with Internet, TV interface, open source software and development tools. This has a chance to allow schools to do something for IT other than simply teach spreadsheets, to give the next generation a fighting chance to compete with the Chinese (though don’t hold your breath). More’s the point, if it ends up running XBMC properly (X-Box Media Centre) -  I get to reclaim a LAPTOP currently doing the job!

Just in time for the holidays as well. Dunno how I’m going fit my oscilloscope in the travel bag, though Smile

IF this remains sub-£30 and IF it really does allow for development of complex Internet-connected gadgets, there is just SO much future for this little toy.  Keep eyes peeled, as soon as it turns up I’ll get something in here. Expect an update maybe Saturday morning.

tmp2D1C

DIY Arduino

While waiting for the first Raspberry Pi to arrive, I’m continuing to work with Arduino clones. I use the name repeatedly just as it’s familiar to those in the field, but essentially we’re simply talking about a minimal ATMEL-based processor board with reset and power components. Having discovered that the Chinese do prototype boards quite cheaply and quickly I figured I’d have a go at doing my own. The Eagle PCB package is free for anyone wanting to have a go up to a certain size board. I’ve used this package over the years but not for a decade so it’s nice to see they’re still in operation and obviously they are very popular with the hobby community.

Anyway, here’s the board so far. This is a “jack of all trades” board as I put stuff in that “might come in handy”.

As you can see, it has it’s own proper 5v regulator (fastened down with some heatsink area) and power connector, standard Arduino-type general connectors and the usual microchip, xtal and a crude 3.6v supply via a couple of diodes. The connectors include the normal programming connector, ICSP and one (lower left) specifically for the cheap Chinese RF modules. ~I’ve also put in a 24c65 socket there as the Atmel chip has only 1k of EEPROM for storing logs etc. and the socket I’ve added lets you add a 24c65 or 24c256 chip for up to 64KB of logging or other storage (can’t use for programs).

The next step is to find out the realities of actually getting prototypes made in China. I looked all over the UK and I might be missing something but there’s no-one here to even remotely compete on prototypes – these work out at around a fiver each for 10-off which means if I’ve made a mistake it’s not going to break the bank – but it’ll be weeks before they turn up – so more information at the time… I’ve jokingly called the board “UberBareBoard”… I’ll find out how super it is (or not) when they arrive.

 

MyDuino !

 

On the subject of iPads -  has anyone noticed the utter lack of anything new and exciting recently – same with iPhone – it’s as it people are running out of ideas. A good old fashioned (but not old) adventure would be nice, not one of those silly “guess the hidden objects” but a proper adventure…

Raspberry Pi

The Raspberry Pi is now OUT, apparently, if you go to their website it suggests RS and Farnell (would not have been my choice) -  in reality RS have only an interest form at the time of writing and the Farnell site presumably can’t handle the strain as it has given up.

The model B with Internet connection has a lot going for it – at the price it could easily make a remote controller with the addition of a relay or two – so remote control of heating etc all become possibilities. I just hope they don’t get carried away with success and start jacking prices up.

 

Peter Scargill

Willow Design