Last Tuesday we had our 23rd £5 App event, given that it is only our second event this year we chose to let people “show and tell” about the things they built this summer. We had 9 speakers, I bought the beer, John baked the cakes.
Emily is working on an iPhone app with me that we’ve named SocialTies, it helps you find your friends and ‘similar people’ when you’re at an event or conference. It was inspired by the fruitless hours I’ve spent at events wondering if I’ll ever find anyone I know…
Over the last couple of months I’ve been building up a social microprinter (inspired by Tom Taylor‘s implementation and Matt Webb‘s original idea). Here’s the current version – Arduino+WiShield+CBM231+off-site server (powered partly by BenOSteen’s Python driver):
The goal is to build a social microprinter – a printer that’d live in a social environment (currently The Skiff co-working office in Brighton) which would help bring people a little bit closer. Currently it prints tweets (for ‘theskiff’) and shows events, later it’ll show recent Gowalla check-ins and maybe some local news headlines or the weather (but there’s got to be better stuff to show, right?…ideas on a postcard please).
My original intent was to build a device that could be stuck on the wall in a cafe, it would show tweets on a screen (probably under the cafe’s or Brighton’s hashtag) and let non-Internet folk post their own messages back. Doing this nicely would have needed a screen, machine, wall space etc – using a receipt printer seemed like an easy way to prototype the idea.
Jumping forward, here’s an early version – this is a CBM231 connected to my Ubuntu laptop via a USB->RS232 lead (note – this lead is good, the cheap ones on eBay can be bad – see below). Here I’m using BenOSteen’s Python driver to send tweets via serial to the printer.
This device has done the rounds, here it is on display at BuildBrighton’s talk to the British Computer Society:
Here it is in use at Likemind Brighton showing international #likemind tweets as other groups meet around the world on Friday morning (note – unicode converted to ‘?’ as I haven’t figured out if/how to get international characters out of the printer yet!):
It ran during the weekend of Barcamp Brighton and printed out barcampy stuff, I added some notes about local cafes and a job ad for one of the companies:
The goal all along was to build an independent controller (so removing the laptop from the equation). For this I coupled an Arduino with a WiShield 1.0. The WiShield libraries are easy enough to work with, after an hour’s experimentation I got WPA2 working (it takes 25 seconds to negotiate the connection on each attempt), we use WPA2 at home and in The Skiff.
Coupling the Arduino to the printer was easy enough, I have been trying (and so far failing) to get a Max233 chip acting as a voltage level converter so for now I’m using a pre-built RS232 Level Shifter. This converts the Arduino’s 0V/5V TTL to +12V/-12V RS232 levels (powered from the Aruino’s 5V out). To output text I’m using Roo Reynold’s Aduino sketch, this handily includes some control codes to cut the receipt after printing.
Next I wanted live data. At first I simply put a short plain text file on a web site, used the WiShield to fetch it and Roo’s code to print it. Now I’m using a hacked version of Ben’s code to write tweets (including bold and underline control codes) to a text file which is stored online (microprinter.ianozsvald.com), this ready-to-print file is grabbed over the WiShield, printed and then cut. The online file is updated every 2 minutes.
The final tweak was to add a button to the printer. Using the Arduino’s demo button sketch I hooked up a big thumb-sized button. The Arduino’s main loop is looking for a combination of ‘at least 5 seconds have passed since the last print’ and ‘button pressed’, then it’ll kick off the web request for new data. Once this request returns it prints out the text.
I look for the pattern “————–” (14 dashes) to start and end the message, before this we get HTTP headers (from the WiShield) that I didn’t want to print.
Here’s the finished hardware:
This is a WiShield 1.0. The button (shown just out of shot top-left) is connected 3.3V->button, button->Pin 6 AND Ground (via a 15k resistor). For the printer I’m using Pin 8 for tx (blue lead on the RS232 level converter) and Ground, the level converter is powered by the 5V out.
Here’s the connector:
The connector is overly-connected in this image. I think all you actually need is Pin 2 from the RS232 Level Converter to Pin 3 on the 25 pin connector along with Pin 5 (GND) to Pin 7 (GND on 25 pin connector). With yellow wires I’ve shorted Pins 4&5 and 8&20 but I think this is overkill (they’re used for bus control but they’re probably ignored in this configuration). Here’s a full pinout.
During all the hacking our faithful cat Mia has attempted to assist whenever she could. Here she’s taken ownership of the bag used to transport the early versions:
Along the way I also acquired an Epson TM T88 II receipt printer, it is ‘just another serial printer’ but takes different control codes (and it looks like it might have a smaller character set than the CBM 231). As yet I’ve only tried printing plain ASCII, I’d like to investigate further and build a library that supports this printer too.
Note on buying leads from eBay! be aware that if you buy cheap leads from eBay (e.g. £2 silver/blue leads) then you might end up with a pack of 5 (because if you buy 5 and one breaks, you’ve got 4 more that work, right?), you might have 5 dead-on-arrival leads. You could then report the problem and the nice people could then ship you a replacement set, but then you might discover that you’ve got another 5 DOA leads. You have been warned.
If you’re buying your first microprinter do try to buy a working serial lead with it (it’ll probably be a 9 pin to 25 pin converter lead) – if you get the wrong lead (null modem vs straight serial – I forget which you need!) then you won’t get anything (the bane of my first few week’s of testing). Buy a printer+lead that’s known to work and you won’t go wrong.
Spend the £8 per lead and buy from Amazon if you don’t want to waste hours wondering why your printer is just printing out reams of ‘?’ rubbish:
If you want to build your own then the first best source of info is the microprinter wiki. Roo Reynolds has Arduino drivers (which I hacked a bit for my implementation) that don’t depend on external data sources.
You’ll find my Python server source and Arduino sketch (which assumes you’ve got a WiShield 1.0) here: social_microprinter. Note that the code is horribly hacky, it was written over many short sessions when I could steal an hour or two from other projects.
It could do with being straightened out and commented and a few nice new features would include Gowalla check-in notifications, event RSS reading and weather printing.
Many thanks to my fellow hackers at BuildBrighton for help debugging my early serial problems and to Barney for the lend of his RS232 Shifter (I’ll soon get this Max233 working, promise!).
Here’s the finished, installed unit on the work bench at BuildBrighton in The Skiff (just by the social kitchen space). Once it is a bit more robust it’ll move to the front of the building:
Next Tuesday at 8pm at The Skiff we’re holding our 23rd £5 App event. This is our second this year, we’ve been a bit slow. To make up for being slow we’ve given it the title “Things we built this summer“, here’s our fine speaker list:
Ian (me) on hacking a receipt printer with an Arduino
Having built ProCasts during 2009 (from ‘just me’ to a fab team of four) and then letting it sit quietly for the first half of this year I’m now selling the site as a lead-generation opportunity for a lucky fellow screencaster.
The site continues to generate leads each week – this has lead to some odd conversations where I try to explain that I’m not taking on any work – even though the client might be rather desperate for a UK solution. After another odd conversation a week back I decided it was time to pass the site on.
The site is listed at flippa.com, the auction ends in 11 days. Via the message boards I’m having good conversations with existing screencasters and a few new entrants. It feels good to have built an asset that’ll help someone else win more business. Not only does the site generate leads but it also has solid traffic with a Page Rank of 6 and the business gets linked in forums by friendly third parties. Flippa.com has the full details, there’s also a short link on the ProCasts blog.
The event was organised through Philip and Declan of PlayGroup, they use Hector’s House for arts and science gigs (thanks BuildBrighton for the connection!). Cheers chaps, it was exactly the space we needed!
“Seb’s Slightly Failed Music Career”
Seb spoke on the highs and lows of forming a band, showed previously-unseen footage and generally gave the lowdown on how it all works. Rick-rolling was included. Seb has his own write-up.
Sadly Seb’s hard-drive died after the talk taking all his transcoded footage but on the flip-side Seb inspired Simon to share footage from his old cover band.
John and I are very pleased to announce our upcoming music-themed £5 App Christmas Special on Wednesday 2nd December, 8-11pm at Hector’s House in collaboration with the lovely Playgroup guys. Please do the usual – sign-up on Upcoming so we know how much beer to brew for you all. If you don’t know what this is then see last year’s Xmas Special write-up and details of all the previous events (with videos).
We want 40-60 of you along this year so please spread the word – Tweets and blog posts would be hugely appreciated!
Seb Lee-Delisle – “My life as a wannabe rock star at the birth of the internet music boom” – full description below
Toby Cole – “Zero to Theremin in 20 days” – How BuildBrighton built a feature rich, ultrasonic, laser etched MIDI controller in under three weeks”
Tom Hume – “You’re all an orchestra, get over it” – Bluetooth devices will interact with the audience to create changing ambient music, created by Future Platforms for a Music Hack Day
Jim Purbrick – “A short talk on the Mrmr/LiveAPI guitar mounted iPhone ableton live interface by the head of Second Life Europe and later a demo with 100Robots”
lastminute.com labs – Bottle-Rock-It, a music game for n iPhones where (with any luck) n > 3 (Richard, Russ, Sam, Mathias)
100Robots – Jim and Max Williams play live and loud for us
Seb has the main talk, his full blurb is:
“Before Seb Lee-Delisle was peddling his digital creations, he had an entirely different life. He spent most of his 20s setting up Solar Records and promoting his band Stargirl (later Laine). Investing over £50,000 of their own money, they released their own CDs, made it onto the radio and TV, played in front of 30,000 people, recorded at George Martin’s Air Studios and had full page spreads in the nationals.
They were at the forefront internet music boom of the late 90s. The future was looking rosy for this group of dynamic 20-somethings. So come and find out what it was like, how the hell they got the £50K, and why their plans didn’t quite reach fruition…”
I’m not entirely sure of the right tag for flickr – it seems that ‘bcb4’ (which I’d thought was official) conflicts with BarCamp Bangalore and BarCamp Boston…ho hum. Anyhow, here’s one of mine:
My session was a 30 minute workshop on ‘Screencasting in 7 minutes with Jing‘ (now picked up by TechSmith – thanks Betsy!), I signed-up 7 new people to screencasting including freelancers and a Thales employee so I consider that a Win. The link has a break-down of what was covered, a video of the session and the resulting screencast by Jez via my machine.
In the session I covered the following as examples of how screencasts are used by others:
Jay’s Gibraltar Software screencast produced in 3 days with Camtasia on Windows (via my friendly critique)
Google Chrome screencasts for examples of 10-20 second feature tours
DropBox intro screencast which shows two computers syncing (via a virtual Windows instance) – see the Windows desktop about 1/6th of the way into the video