UptownMaker

About two years ago I decided I was going to figure out a cheesy inductive power coupling circuit. I sat down one Sunday, started plugging some stuff together and this is what I ended up with: This is the circuit I brought with me to the "bring-a-hack" dinner at Harry's Hofbrau that Jeri Ellsworth organized on Sunday night. You can see that the LED in the jar is lit- the jar is really just a gimmick and the little parasite works better outside the jar. The circuit is very simple: the IC in the middle is a 12F683 that I programmed up to be a square wave generator (someday I'll blog that project, but for now, I'll just say that the oscillator frequency is jumper selectable and it can be set to either update constantly when powered or set and forget the output frequency and duty cycle) running at 50% duty cycle and (approximately) 71kHz. The square on the right is a bit of ~28ga magnet wire wrapped a few times around four screws. Power is delivered to it by a tr...

On the heels of a few tweets regarding linear voltage regulators that I passed with a friend yesterday, I think I'll do a couple of posts on voltage regulation. First, the general concept: voltage regulation is the creation of a stable, low-impedance DC voltage source from an unregulated DC voltage source.  Examples of unregulated DC voltage sources are batteries, "wall wart" type AC/DC converters (even though many of these create very good voltages (these days, anyway), you should always assume that you (or someone else) will plug a different supply in), car cigarette lighter sockets, rectified and filtered transformer outputs, solar panels, fuel cells, dynamos, and fruit with pieces of zinc and copper in.  In fact, pretty much anything other than a locally generated voltage from a well-designed regulator circuit should be treated as an unregulated source (for design purposes, at least). This first post will concentrate on linear voltage regulators.  Sometimes you...

Once you've got it all together, where do you use it? My workspace is divided in half- an electronics bench with tools and a PC station.  The PC desk is boring- two 19" monitors, speakers, printer, etc- I won't bore you with pics of that. There are only a couple of things I really want to mention here as being special about my desk.  First, the knife holders.  These are the standard type of wall-mount magnetic knife mounts.  Mounted vertically (because they were too long for horizontal) they hold my small tools- little screwdrivers, a wire stripper, a side cutter.  I have duplicates of all of these tools in the mobile kit but it's nice to have them handy. Secondly, the whiteboard.  It's magnetic so I can stick stuff onto it, but it's really more useful as a whiteboard- I'm a big believer that whiteboards are the stuff engineering magic is made of.  I have four of them in my cube at work, and one of the smartest facility design elements I've eve...

In part 1, I covered my mobile electronics kit .  This time around, I'll look at my mobile electronics toolkit. While the mobile kit contains (almost) everything I need to do some breadboarding of circuits, more permanent hacks, installations, disassembly of finds and really fun stuff is all bound to require more advanced tooling than the cheesy $5 multimeter (that link shows it for $13, but it's available locally in the Twin Cities at AEI for less than $5, and with a bulk discount option)(yes, I have purchased multimeters in bulk) and adjustable wirestripper in the kit.  After a few scrambling debacles where I realized I didn't have what I needed to finish the job, I decided that I'd best come up with a toolkit that I could use at home and on the road. After some hemming and hawing at the local Home Depot, I bought a Stanley XL Tool Organizer , which is a nice fold-up unit- essentially, two of the more conventional see-through plastic lid boxes that fold up arou...

Mr. Jalopy's famous side one, track one of the Maker's Bill of Rights is all well and good, but more basically, if you can't FIND it, you don't own it. Owning an object has a cost, however minor, associated with it.  You'll have to move it if you change residences, you have to keep your kid/cat/ferret/sugar glider away from things you don't want smashed/pissed on/drug under your couch/scent marked by a weird oily forehead gland, and clutter (IMO) occupies mental real estate we can usually ill-afford to waste.  If you're going to pay these costs, you should take care to keep your gear well organized so these costs aren't wasted when it comes time to use something. As a hackerspace-going maker, I find myself with an additional constraint- if I want to work on a project at the shop, I need to either bring what I need (tools and materials both) or be darn sure I know what and where stuff at the shop is.  My solution is a robust, scalable, compact group ...

Okay, hardcore nerdery here.  Sorry to the non-believers in the audience, but... 5.  SMT technology for hobbyists. Some will argue the point, looking back with nostalgia at the days when every IC was available in through-hole and sockets abounded, but I for one welcome our minuscule highly integrated overlords. Ten years ago, when I bought my first parts from Digi-key, it was inconceivable to me that SMT parts could be usable on an at-home basis.  Now, the proliferation of adapters (such as Capital Advanced Technologies' excellent "Surfboard" series ), cheap hot-air and fine-point rework stations , excellent reflow tutorials , and extremely low-cost low quantity PCB fabrication services (like BatchPCB and the DorkbotPDX group buy ), it's now completely and totally reasonable for a hobbyist to use SMT parts to realize extremely advanced designs in surprisingly small amounts of space. All that's really needed is the right attitude.

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...