UptownMaker

So, I have a stream of data from a FireWire device I need to interpret as an image. I'll not get into the how or why of this, but the problem is pretty simple: take a file which is 250,848 bytes long, with each byte representing the 8-bit grayscale intensity of a single pixel in a 536 x 458 pixel image, and reconstruct that image. Turns out, finding an app to do this is a non-trivial problem. Sure, I could write something to do it (in the past, I've written a Scilab script that plots it, but that takes a lot of memory, runs slowly, and generally gives me few or no tools to deal with the "image" resulting, besides my eyes), but I KNOW this is a solved problem (my favorite term of late) and anything I came up with would likely be a south-pointing chariot. In the end, I turned to my old friend, ImageJ . ImageJ is a powerful, free, Java-based image manipulation and analysis tool. It's no replacement for GIMP or Photoshop, but it provides a very simple interface to...

With apologies to Quentin Tarantino... For a 10-year-old problem, the capacitor plague has been bizarrely present in my life recently. It started a couple of weeks ago when a coworker offered me an LCD TV that was "flaky" as scrap (my scraphound predilections are by now legend among those who know me). Being the upstanding gent I am, I pointed out that it was probably bad caps, and I found and replaced the buggers for him. A friend in Iowa sent me an e-mail, asking for help debugging a dead plasma he'd been gifted. He hasn't found bad caps yet but I'm fairly confident he will. My PC was dead the other morning, when I got to work. Guess why? A couple of months ago, I found a dead 17" LCD in the trash bin at the office. By now you should know how I fixed it. A tweep I follow posted this article this morning. This is fascinating for me in that it hits a number of points that people fail to understand about electronics: They wear out, but certain component...

A friend was asking after a circuit for making pulses from a pushbutton on push and release. Two ways immediately suggest themselves- using a PIC and using a differentiator. The PIC is easy for me, at least- I have a small stock of 12F683s which are 8-pin devices. Add a bypass cap and you're in business- you could even reprogram it to change the delay, debounce the input, etc. Of course, not everyone has a PIC programmer, and I feel like it's a pretty trivial app for a PIC, so I'll not talk much more about it. The differentiator circuit is a little more involved. Apologies for the crappiness of the image- LTSpice doesn't generate great output images, for one, and this was part of a larger image (it started NPN based, and generated negative going pulses; that's where Q3, Q4, etc etc went). V3 is the switch- in the application, it should be a 100-ohm pull-up to 5V and a switch that yanks C2 to ground when it's closed. R4 pulls up the base of Q3 and Q4, keeping the...

For those in the electronics world, SPICE simulation can be a great way to answer the "will my circuit work as advertised" question without breadboarding. It's a great sanity check- if it don't work in SPICE, it won't* work on a breadboard. LTSpice is Linear Technologies' own incarnation of SPICE. It's a nice little product, and comes with models for many of Linear's products (power supplies, op-amps, etc) along with many supporting components from other manufacturers (diodes, transistors, capacitors, inductors, etc) and generic parts (555s, LEDs, etc). Obviously, they provide it expecting people to download it, sim up a solution involving Linear parts and then sell eleventy-billion a year, thus providing a nice income stream for Linear (and it works- LTSpice makes it much more likely that I'll reach for a Linear part for power supply design than another manufacturer's parts). But for the tinkerer, it means that there's a free, very po...

A few weeks ago, I purchased 10 Atmega328P's from Mouser , naively thinking it would be easy enough to get them working on a breadboard as an Arduino sans the fancy (expensive) board. I was planning to use an FTDI USB to TTL serial data cable to bootload (I bought a 5V one, then realized that the two 3.3V ones I already had would work fine- lesson one of this saga). I also bought a some 16MHz crystals and the appropriate capacitors. At this point, I want to extend my thanks to whomever it was that decided a 6-pin AVRISP compatible ICSP header would be a value-add to the Arduino. I know that 95% of the Arduino users out there will NEVER use it, but I am very grateful. So, first hurdle- I figure I'll take one of the 328s and upgrade my Arduino (it was one of the, what, six? Duemilanove's that shipped with a 168 from the factory). Supposedly, the Arduino IDE has the capability of loading the bootloader onto a blank chip through an AVRISP, but I'll be buggered if I co...

Quick and dirty math post- The media reports the balloon was about 20' x 5'. Modeled in SketchUp as a 20' diameter sphere, shmooshed to a disc with a 5' vertical, that yields ~1000 cu. ft. of helium, or ~28,300L. As we all know, helium can lift 1.113g/L, for a total of about 31.5 kg of lift for that volume of gas. A quick Google search tells me the average 6-year-old boy weighs 46.2 pounds, or 21kg. That leaves 10.5 kg for the mass of the craft itself- about 23 pounds, or slightly less than the weight of three gallons of milk. I guess it's plausible, but I'm skeptical. I think it will come out that he was never on board in the first place.

Some general notes on the whole "Essential Skills" post. A couple of commenters mentioned that it is a bit heavy on electronics. True; partly that's because I'm an electrical engineer, but it's also because, in my experience, it's also where many makers (aside: I will continue to use that term; I came to my personal peace with it during the discussion about what to name the Twin Cities Maker group) "fall down" and lose confidence or run aground. Electronics is a massive sphere, and my hope, by including those things on the list, was to encourage people to develop familiarity with the most basic, most useful aspects of it (at least, as far as general making is concerned), rather than feeling overwhelmed by the whole thing and steering clear of electronics projects altogether. Some of the coolest projects I've seen were banged together by people with little or no electronics experience, just the confidence to go forward and the willingness to m...