What we really want...
Not so long ago, a hardware hacker called Jimmie Rodgers decided to solder 126 LEDs onto a small circuit board that could be plugged into the Arduino microcontroller kit. He dubbed it the LoL Shield: LoL for "lots of LEDs", and shield because that’s that’s what Arduino add-ons are called. Ciseco Pi-Lite LoL Shield for RPi: …
So actually you can drive this from a laptop running windows or linux too.
Perhaps even from an Android phone / tablet using USB to Serial without the RS232 line driver.
The Chinese are cranking out LED matrices by the square km. They're typically advertised in the Arduino category, but they'd work with anything with I/O pins.
Subject item is priced well. But non-free S&H often ruins an otherwise decent price.
"But non-free S&H often ruins an otherwise decent price."
As someone working for a non-tax-avoiding UK online retail business, I often wonder how people have come to the conclusion that all shipping should be free nowadays. Sadly, none of the couriers we work with are prepared to move our stuff around the country without requiring some kind of payment in return (how selfish of them!). Perhaps you know of some secret underground network of couriers who act out of sheer goodwill? If so please let me know!
And yes, I know why people expect this nowadays: Amazon. But surely you must logically understand that the only way this can be achieved is either through sticking markup on items to cover the margins, or by making savings elsewhere such as nominally running all your profits through the "greater republic of nonexistia", and thereby making the UK taxpayer pay for the shipping anyway, albeit indirectly.
Do you pay high street council tax or just an Industrial Estate council tax?
Assuming you mean me, I dunno - I'm just a code monkey :) But we're not on the highstreet so probably the latter.
I'm still happy to shop at Amazon. I'd rather retail businesses didn't have to pay pointless taxes, or found a legal way not to, than have to pay (often excessive) P&P. It's just a shame that the tax loopholes are only open to multi-nationals. Of course, the easiest way to close the loophole is to scrap the tax. Courtesy of PAYE and VAT I pay enough tax as it is thanks very much and forcing retailers to pay more will mean they just pass it on and I'll be paying even more tax.
> I often wonder how people have come to the conclusion that all shipping should be free nowadays.
We all realise that nobody is suggesting Royal Mail should deliver stuff for free. However there is a valid point behind this comment - someone's making a nice little earner from P&P - and VAT on P&P.
Take for example an Arduino prototype shield, purchased from a UK supplier. The delivery costs alone are listed at £4.15 - with VAT payable on top.
Now consider (very possibly) the same board, bought from a supplier in China - both suppliers were chosen at random, so no intentional cherry-picking - The board including P&P comes to a grand total of $4.50. So the cost of sending a board half-way round the world to my letterbox is somewhat less than what the UK vendor charges just to send the same sized packet at most a few hundred miles within the UK.
Given that when the board arrives in the UK from China, it's RM who handles both deliveries you have to wonder why it's more expensive for the same carrier to deliver the same package, just because it was posted in the UK, not China? Who's making the money - is it the UK vendor (who's delivered cost for the same board is roughly 6 times what the Chinese website is charging) or is it RM stiffing the UK company who merely pass on their costs?
Answers on a postcard please ... if you can afford it.
If you are just sending out a few boards then you need to:
Send kid down to staples to buy padded envelopes
Get kid to put them in envelopes,
Make sure correct label is stuck on envelope
Take to post office
Weigh them, pay postage
Compared to sending out 1000s of items with a production line of kids paid Chinese minimum wage and a container full of padded envelopes bought at Chinese prices from the company next door. And then a bulk deal with China post.
We used to charge 25quid for a replacement serial cable for one of our industrial products. Our customers probably hated us for ripping them off - but by the time we had bought them from RS, dealt with all the stocking, taking orders, packaging, posting etc - all to ISO9001 - we were losing money.
Dealextreme and the like manage to surface mail cheap crap for free by regular post, so either RM is doing them a great deal on the final delivery or they have really really good margins
Just the other day I found four eBay deliveries in my mail box, all from China or Hong Kong to NA in two weeks, free shipping. Items costing $2 to $4, LED strips and such.
I see your point. I couldn't pay the postage to air mail even one of them back to China for the total price I paid for all four items (including the items), delivered.
There's a very strange asymmetry in postal rates for air mail small packages. I wonder if the Central Committee included some Cheap Shipping Policy in their 5-Year Plan? Maybe they're running their Post Office at a $100M loss to enable Billions in small business.
SOMETHING is going on.
Chinese eBay sellers typically use Small Packet AIR Mail. For the packages with tracking numbers, one can see it moving airport to airport. About two weeks to east side of North America.
"Dealextreme and the like manage to **surface** mail cheap crap for free"
DealExtreme typically uses China Post **airmail** or Hong Kong Post **airmail**. The one disadvantage is that they sometimes take a few days (or more) to get around to actually shipping it.
In contrast, most eBay sellers seem to ship within a day.
I'm with Larry F54. If there are any online retailers out there wondering why I went through the process of registering, only to abandon my shopping basket and never come back, it's because their silly P&P charges were only disclosed at the checkout.
"SOMETHING is going on."
Not really. Think of it on the flip side, if you buy peanut butter m&m's in the states they are under a dollarish right? so ~60-70 pence. They are not sold in the UK if you look on amazon they are from £1.60 ($2.41) to £4.34 ($6.56). A USPS envelope rate for a single pack is $2.to the UK (assuming 2 ounce/56g package weight). Going the other way though a single envelope is £2.48 ($3.75). That is comparing two comparable western countries and you have a large price difference and i would wager that some of it is down to RM's labor cost per envelope being higher then USPS' who in turn will have a higher cost then China Post (things like jet fuel etc will be roughly the same all over)
So you have two options you can get someone to buy them in America (for much cheaper )and ship to the UK and come out around the same price as buying in the UK(for small amounts, larger amounts will attract a customs charge) or you can buy them in the UK from a distributor who has already done all of the above + paid import tax and pay slightly more.
There is no great Chinese conspiracy here it is a simple case of economics. It is also important to remember that p&p is postage AND packaging which not only includes the box but the labor involved.
You get a down vote for "and thereby making the UK taxpayer pay for the shipping anyway, albeit indirectly."
The tax payer doesn't pay for shipping indirectly or even going all round the galaxy. If the company avoids tax, then it means you pay less for the product and it's P&P and you can then spend the money you didn't pay in tax on something else, maybe an even bigger LED matrix. But that was your choice. If the really big company paid loads of tax then you don't get a choice, the state would spend it on welfare and many other useless projects such as HS2.
And the really big company is following all the legal rules and regulations. Blame the politicians for setting up the complex tax laws, not the companies for following them to the letter.
will not work.
Exactly why it won't is left as an exercise to the writer.
I'm pretty sure that's what I keyed in, and whatever I did key in did work. Carriage return, \r, not required here.
Well thanks for that. I see the linux community is alive and well with their sharing of knowledge, friendliness and general willingness to help.
re: sudo echo $'The Register on Pi-Lite' > /dev/ttyAMA0 won't work
For those that don't know, when you mix redirection with sudo, it's your (non-root) shell that tries to do the redirection (>) part and if you don't have write access to the target the whole command will fail.
You need to use this idiom instead:
echo 'something' | sudo tee target
Rewrite the original line and if becomes:
echo $'The Register on Pi-Lite' | sudo tee /dev/ttyAMA0
Also, I'm not sure what that $ is doing in that line. Typo?
Thenkyou for replying. It's one of those types of problems that I've come across before, but I couldn't see it just by looking at it.
"Also, I'm not sure what that $ is doing in that line. Typo?"
AFAIK echo $'The Register on Pi-Lite' can be reduced to echo The Register on Pi-Lite
The $ is only needed because of the ' '
"The $ is only needed because of the ' '"
Sorry about that , that's nonsense, IF you put $ in you NEED ' '
Of course, "sudo echo" is only a pseudo-echo (oooh, 80s flashback).
sudo echo $'The Register on Pi-Lite' > /dev/ttyAMA0
can be re-written as
sudo `echo "The Register on Pi-Lite" > /dev/ttyAMA0`
When you use shell redirection, the file is opened by the shell process, that runs under the original userid. Sudo launches the command under root userid, and if it opened the file it would be able to, but it does not, it just uses stdout that was already opened by the shell. If it could.
If the command worked, it means that the file was writeable for the original userid, and running without sudo would also work. So, sudo is either unnecessary, or does not help.
Whilst you're on Ciseco's site, check out their RF modules based on TI hardware, they're literally plug'n'play wireless serial comms. With the 1st revision of their XRF boards I achieved up to 3.4km communication without upgrading the whip antennas to parabolics!
Sorry off topic. To teach programming, the Pi needs to come up right into a programming shell, like home computers did in the 80s. Otherwise children will just use them to surf the web. If your Amstrad/Dragon/Oric had been able to surf the web, would you have learned BASIC ?
I've never used one, but does it not come up with a Bash prompt after you log in?
In any case, writing your programs in a text editor or IDE is much more user friendly than typing everything in at the command line like you did back in the BBC BASIC days.
Hmm... I'm not so sure. If you can bring up a basically GUI (a la RISC OS) you can program, run an IDE, should you so wish, check the Web for your online programming manual, but the rPI doesn't really have enough oomph to do full on web surfing. There's almost certainly going to be a machine running a pretty good web browser in any home with an rPI, so why wouldn't someone use that, if that's all they want to do. You can't force people to be interested in programming, but an rPI is an easy way to dabble and become more advanced at very little cost. The main issue with "the home laptop" is that it's not something that you can really let your kids trash, as it does too much other work.
"I've never used one, but does it not come up with a Bash prompt after you log in?"
By default (as in answering all the config questions with the default answer when you plug it in the first time) you will be presented with the desktop GUI after powering up and logging in.
As supplied the Pi comes with IDLE and IDLE3 which is a pain since there is no clear guide for the total beginner as to why there are two and what difference it makes when you use one of the other.
The IDLE editor/python shellything is good as far as it goes, but has some quirks which, added to the quirks that can present with the Pi "just because" makes life hard too*.
You can configure the Pi to drop you into a console (bash prompt) instead of a GUI but the console font is so small you need electron microscope eyeballs to read it. Better to fire up a terminal in the GUI which can be reconfigured to display better font/color combinations.
I plan on trying to make ScITE on the Pi as it is a much better way to script & test than IDLEn and styles a bunch of other useful languages out of the box.
The browsing experience with the Pi as delivered is rather basic. The kids aren't going to be impressed with that feature, so I suspect the internet distraction will be less of a problem. You could do what I do and unplug it from the net altogether. After all, you don't need the network while programming if you download the python manual to the SD card.
* For example: I found that to cure the talked about - but only behind closed doors - double click insensitivity I had to add a powered hub (direct connection of the mouse did not cure the issue) but that after about ten days uptime the Pi began to behave very oddly when IDLE/3 was running. Letting everything cool down overnight restored sanity. Why? Who the Pi knows.
"If your Amstrad/Dragon/Oric had been able to surf the web, would you have learned BASIC ?"
I seem to recall dialing into Newsgroups and BBSs. Web?
Sure it has Bash, all sorts of eco systems including a python programming environment, a special graphical programming tool for younger children, but setting up all of that requires patience and adult assistance. I have a Pi and bought others for nephews. They use them for surfing mainly. Pi just doesn't say "programme me!" like an 80's micro. Multi-window GUIs are distracting.
Christmas 1982 -> you were programing by lunchtime, remember ?
Balls to surfing the web. I left my newly setup Pi alone for 5 minutes, and my kids were running the preloaded Python games, and dragging things about in Scratch - OK, they didn't get anywhere (at an average age of 5, I can't blame them), and I was woefully inequipped to point them in the right direction, but it's a start!
Dumping the user at the command prompt would probably scare most people off (if you've never used one before, you'll be sorely disappointed that they don't work like they do in films!) - a GUI is familiar enough to encourage some exploration.
I do agree with the comment about the presence of 2 Python interpreters being confusing, though.
"If your Amstrad/Dragon/Oric had been able to surf the web, would you have learned BASIC ?"
I know some of us wouldn't have spent quite so much time with the shower section of the Grattan catalogue
"By default (as in answering all the config questions with the default answer when you plug it in the first time) you will be presented with the desktop GUI after powering up and logging in."
And prominent on that default gui is an LXTerminal icon. I'm looking at it now, and I'm sure I didn't have to add it.
Personally I run my Pi remotely via UltraVNC, graphics desktop and all. Works beautifully.
BUT........Does this mean that LOHAN can have a groovy light display?
... those single column displays? A single column of rapidly switched, very bright LEDs that worked through persistence of vision. You looked directly at it and saw a single thin column of sparkling red points, but then moved your head or eyes and you could see the word SMIRNOFF spelled out on your retina.
Did I just dream this? Or was it done with lasers?
POV displays. Clocks come to mind, but very popular on Instructables etc.
Those columns of a single row of LEDs? Massive Attack used green ones in their comeback tour a few years back.
There are a number of persistence of vision displays already featured at www.raspberrypi.org. Not recently so you may have to look a few weeks or months ago.
For starters, try http://www.raspberrypi.org/archives/tag/pov
I remember buying a frisbee that did that (from the Ideal Home Show, of all places), and those wierd, metronome-style clocks were a brief fad.
16x32 RGB LEDs, US$40.
Why be monochrome?
The dollar-quote $' is an i18n thing. It allows translation of the string if one is available.
... Cisesco get a nice little cease & decist letter from Cisco's trade mark lawyers?
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