May 12th, 2011

Whoa, looking forward to giving these big ass LEDs a testdrive. 10mm diffused RGB and the first testcase for the LED drivers. The 3mm red one and 5mm strawhat are a quick size comparison to give you an idea how big 10mm actually is (personally I never saw 10mm ones before irl).  Gotta love Chinese manufacturers :D

TLC5940 driver boards

May 11th, 2011

So with all those LED drivers lying around it’s time to do something fun with them. Given the amount of chips a PCB certainly wouldn’t be overkill so I whipped one up. It’s the max size Eagle freeware allows, but everything fits nicely. Of course using SMT would enable a smaller PCB, but since the drivers are already present, that’s not an option. The TLC5940 comes in 3 packages; SPDIP, SSOP with PowerPAD and QFN.  Soldering PowerPAD packages is a pain because you need to put solder underneat and adapt the PCB to lead away heat. QFN packages have no leads, which is also a pain for a hobbyist. SPDIP is the only one easily used.

Each board has 3 TLC5040 chips and data is clocked in as 8x8x8 (aka RR…RGG…GBB…B). The board is designed to be Daisy chained, including a return path. The return path may offer possibilities to automatically detect the size of the array via the status information bits. It would be nice to have RGB…RGB, but 16 channels per chip isn’t really dividable by 3. Same problem arose when I thought up smaller PCBs, e.g. use 1 driver per PCB.

A potential problem with these big boards is that they’re harder to build into a system which has small dots. The jury is still out on what to use as a light source. Options are (large) regular LED’s, LED strips cut up into smaller pieces, etc. The TLC5940 can drive up to 120 mA, so that allows for a range of options. Using separate LEDs requires a huge amount of hole drilling, so for the time being I much prefer using LED strips. By cutting it into pieces holding 3 LEDs, oval shapes (in milk coloured acrylic) should be easy to accomplish.

One thing I greatly underestimated was the cost of connectors. Usually only a couple are needed, but in this case I’ve got enough drivers to make 15 boards. Each board has 16 RGB channels, which makes a grand total of 240 connectors. The initial idea was to use polarised connectors, but even low cost connectors from Thailand or China drove up the price too much for my taste. To give you an idea, the male part alone costs $140 at Mouser’s! So I settled on using standard angled pin headers and cheap Molex C-grid like connectors. Should work fine, just have to make sure that during hookup the connection is not reversed.

To be continued….

Making popcorn with style

May 10th, 2011

Btw, also worth checking out is this video by the same author!

What to do with these?

May 8th, 2011

Imagine you’ve got a bunch of  TLC5940 ICs lying in front of you and you’re thinking “What can I possibly make with these….”.

Ooooooh the possibilities >:-)

You reap what you sow :-”

April 27th, 2011

US export regulations

April 20th, 2011

Going to play around with a Coolrunner-II CPLD so I thought it would be a good idea to get Xilinx’ free ISE WebPACK. Guess what, that was a bad idea. The US wants my home address and phone number:

US export regulations require that your First Name, Last Name, Company Name and Shipping Address be verified before Xilinx can fulfill your request. Please provide accurate and complete information for immediate processing. Sorry, addresses with Post Office Boxes and names/addresses with Non-Roman Characters with accents such as grave, tilde or colon are not supported by US export compliance systems.

Fucking nazis…. No way I’ll give them the requested info. Hell they already monitor my bank transactions (do they really think any half decent terrorist uses the ‘system’ and risk a big fat red flag behind their name!?). Filling in bogus info does the trick just fine ;)

On a related matter, Mouser does not sell Xilinx products. Looks like an alternative CPLD is needed for any future development.

OV Chipkaart wiki forced offline by TLS

April 17th, 2011

TLS (that incompetent company behind the OV-chipkaart) send lawyers after the owner of ovchipkaart.org. He didn’t feel like putting up a fight, so the information was taken offline. A real shame because the site offered good information on the contents of the OV Chipkaart. Offcourse with the proper knowlegde one can hack the card, but it was intended for educational purposes. Some I fully support, so here’s a link to a mirror. If by any chance that one goes down as well, let me know and I’ll put a copy online ;)

IFPI lobbyist in charge of EU’s copyright policy

April 5th, 2011

Read and weep: original article

Wtf, is this even legal?!

Oh crap…TI acquires National Semiconductor

April 5th, 2011

Another mega company and less market competition, meaning we as developers are going to get screwed anytime now… bah!

Btw, the mail they send contained some pretty ‘funny’ lines:

I want to reinforce TI’s commitment to you, our customer,  as we merge our two companies.

Sure, keep believing that. Your commitment is to your own financial benefit, or you wouldn’t have merged in the first place. You know it, we know it, so just be honest and say management is greedy. Just stop feeding us this corporate bullshit.

National’s 12,000  products plus TI’s 30,000 means more performance, power and packaging options when selecting the right ICs for your application.

Euhm how does that chance anything? By simply adding the other’s productline to your own does not magically bring new more powerful products into existence. Would be a neat trick though.

Our combined sales and applications team of 2,500 will be larger than any in the industry so we can provide more customers with greater face-to-face support than ever before.

HAHAHAHAHA, in which parallel universe!? Give me 1 example of a big company getting even bigger where customer experience an actual improvement.

TI’s fabs and National’s available capacity can enable higher production levels.

Again, how does this acquisition increase something? You could move products from one productionline to one at another facility, but that will not increase you production level. Also I must point out that I love the EvalBot stunt they pulled, but it took 3 months to be produced. Suffice it to say I have my doubts when it comes to production levels (this is not a TI/National specific issue, just head over to Mouser, Digikey, etc and look at some of the lead times)

Ok, enough for today ;)


April 2nd, 2011

Lots-o-markers (sorry no fancy visual thing… can’t insert a map in WordPress?)

Just a 5 minute experiment to see what our public transport peeps have been up to. Seems they opened up their data through an XML based API. Besides it’s a good excuse to take a quick look at Google Maps’ API.