Sunday 20 January 2013

CIS (continuous ink system) from City Ink Express

January is often a time of lots to do and few blog posts.
Maybe it's the aftermath from Christmas, or all these great new hobbies we'd resolved to take up as part of a New Years Resolution. Or maybe it's taken until now for the turkey and Xmas pudding to finally wear off but there's been very little activity at Nerd Towers for a while. It's time for that to stop.

As we've just acquired a new PC and a printer, so there's plenty of setting up and messing about with technology to be done, but then it's back to making cool stuff and playing with  (and making) gadgets once more. While printing from an industrial-sized Xerox is great for press-n-peel and making PCBs, sometimes an inkjet printer is just what you need. We've got to the point where waiting for everything to warm up for laser printing is getting to be a bit of a bore, so invested in a Canon IP4900 from City Ink Express

It's not the most expensive printer on the market, but it has a rear-loading tray which makes it great for all kinds of different thickness materials; some of the top-end printers on their site have a bottom loading tray which is fine for regular paper, but not for plastics and thicker card.

The system comes with five pre-filled ink tanks and was surprisingly easy to set up.
Just uncap each of the cartidges, install them in place and follow the instructions!
It took us a few test prints before all of the different coloured inks started to appear on the page. Using the windows printer driver, a quick "clean nozzles" to get the ink flowing and hey presto! Everything came through fine

We've quite often seen Steve turn up at BuildBrighton with hands covered in inks so were quite nervous about the whole process. But it went surprisingly well and with only the tiniest little bit of ink spillage

Wednesday 9 January 2013

Working Word Clock update

This was supposed to have been a simple one-night project but trying to get to grips with these crazy, massive, 8x8 LED matrices has been more difficult than we first thought.
But, having finally finished our custom alarm clocks project, and waved family farefare for another Christmas, we eventually found time to get the soldering iron out and write some PIC micro code.

The first thing to do is confirm that we're able to correctly address each column in an 8x16 matrix. If we can't do that properly, debugging in future is going to be a nightmare. So we put together a simple routine which lights up a sequence of on-off-on-off LEDs on each column, and had the PIC light each column in turn (in time we'll just speed this up and use persistance-of-vision to make each individual LED look like it's continuously lit up).

Once we were happy that we could address each column and send it a single byte figure to get different LEDs to light up, we hacked together some code to make the "correct" LEDs light up, according to the current time. We've discussed the method on how to do this in an earlier post.

And the code is starting to look good. So far, we've got our clock lighting up the correct LEDs! Here are some examples of hard-coded times and the resulting LED output:

(it has just gone twenty minutes past eight)

(it is twenty five past seven)

(it is nearly ten o'clock)

Compared to the word grid, everything appears to line up correctly for the random sample times we've chosen:

We're currently using the 20Mhz operational clock crystal for our time-base, and an internal counter to keep track of the milliseconds and seconds. We'll have to leave the "clock" running for quite some time to see what kind of drift we get, and how accurate the clock stays to the true time.
(we're hoping that any drift will be disguised long enough to be un-noticeable, since the clock is only actually accurate to about two minutes anyway!)

All that remains now is to fire up the laser-cutter and make a nice fancy etched front for it....

Thursday 3 January 2013

Happy New Year!

Christmas has been and gone and while we had lots of exciting geeky presents here at Nerd Towers, we've not actually had much time for nerding around (though plenty of time to scoff mince pies and leftover turkey). Some people say they prefer New Year to Christmas (Xmas is a time for family, New Year a time for friends and all that). So how did you see in the New Year?

Did you get away to an amazing all night party before walking home with just one shoe in at 4am? Or perhaps you had a quiet night in with Jools Holland's Hootenanny? Or maybe you were up until the wee small hours soldering about 50 audio player pcbs for an alarm clock project that's already running past the delivery deadline? Yup, we were too.

The Daily Mirror was left behind by a relative after Xmas. Please don't judge us!

Check out that festive tablecloth!