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Audiobook finished
Aug. 30th, 2011 07:21 am Faith of the Fallen by Terry Goodkind
I'm glad I stuck with the series because this was a pretty good story.
I'm glad I stuck with the series because this was a pretty good story.
Aug. 30th, 2011
A beginner's project for the modern age
Aug. 30th, 2011 07:46 amLab bench supply from an ATX power supply. Very good video at this site, with a surprisingly decent build (so many electronics build videos these days are total hatchet jobs).
I really need to do this, blinkies I can run from a USB port or a battery but when I start messing with motors I'm going to need some real power.
Converting ATX Power Supply to Lab Bench Power Supply ยป Jumper One
( G+ comments below the cut )
I really need to do this, blinkies I can run from a USB port or a battery but when I start messing with motors I'm going to need some real power.
Converting ATX Power Supply to Lab Bench Power Supply ยป Jumper One
( G+ comments below the cut )
Anticipation
Aug. 30th, 2011 11:57 amSounds like my RepRap is about to ship, I may have it by the weekend. They emailed me this morning letting me know that they didn't have any RAMPS 1.3 kits left, would I mind a RAMPS 1.4 kit, the caveat being that there's some surface-mount soldering? It's just electrolytic caps and some SMT resistors, so I said "sure." They also offered a completed 1.3 electronics set, but I figured they could save that for someone that needed it, the 1.4 kit is only maybe 45 minutes of soldering and should be fun.
They also apparently had some trouble with the 5/16" stainless steel threaded rod so they want to substitute M8 metric rod. I'm all for that anyway, I friggin' hate imperial hardware (sorry, battle cruiser fans) and wish metric would have taken hold back in the 70s when we tried it the first time. I only ordered a "hybrid" metric/imperial unit because they usually ship faster.
They also apparently had some trouble with the 5/16" stainless steel threaded rod so they want to substitute M8 metric rod. I'm all for that anyway, I friggin' hate imperial hardware (sorry, battle cruiser fans) and wish metric would have taken hold back in the 70s when we tried it the first time. I only ordered a "hybrid" metric/imperial unit because they usually ship faster.
Blinkie power
Aug. 30th, 2011 06:55 pmAs always, power source is what drives blinkie design. A single lithium cell worked well for the 2011 design, but 3 volts won't cut it for blue or yellow LEDs, too much forward voltage drop.
Today I've been thinking that a single AAA cell into a 5 volt boost power supply might be doable. I priced out the parts and the with battery holder it comes to about $1.50. The downside is that it's mostly surface mount parts; the boost regulator is only really available in SMT, and most parts are way cheaper in SMT (the exception being the inductor, which is way more expensive in SMT, but an axial inductor could easily be surface mounted manually by just bending the leads down.
But then it turns out that 1-5 volt to 5 volt circuit boards with a USB socket soldered on cost < $4 shipped from China. Simply removing the USB socket then soldering it to the board as a sub-assembly would eliminate sourcing all those parts and more importantly would eliminate that surface mount soldering. It might be the way to go.
A single AAA alkaline cell contains about 1.5 watt hours of power; the CR2032 I used last year has about 0.675 or less than half that power. There is some inefficiency involved in the boost converter of course, but it's still a good deal, and AAA alkalines in 100 packs are cheap, 15 cents each or so.
( G+ comments below the cut )
Today I've been thinking that a single AAA cell into a 5 volt boost power supply might be doable. I priced out the parts and the with battery holder it comes to about $1.50. The downside is that it's mostly surface mount parts; the boost regulator is only really available in SMT, and most parts are way cheaper in SMT (the exception being the inductor, which is way more expensive in SMT, but an axial inductor could easily be surface mounted manually by just bending the leads down.
But then it turns out that 1-5 volt to 5 volt circuit boards with a USB socket soldered on cost < $4 shipped from China. Simply removing the USB socket then soldering it to the board as a sub-assembly would eliminate sourcing all those parts and more importantly would eliminate that surface mount soldering. It might be the way to go.
A single AAA alkaline cell contains about 1.5 watt hours of power; the CR2032 I used last year has about 0.675 or less than half that power. There is some inefficiency involved in the boost converter of course, but it's still a good deal, and AAA alkalines in 100 packs are cheap, 15 cents each or so.
( G+ comments below the cut )
Prototype museum started
Aug. 30th, 2011 08:49 pmI got those machined pin sockets in today and got my Duck 20 prototype blinkie working again. I wanted to have it in running condition for historical reasons, and also if I wanted to do a talk on development at some point in the future.
For a few months I have been thinking that in the future I'd lay out my circuit boards so that as much as possible the traces would be on the bottom layer and the top would be only vias, so that they'd be easy to jumper or even replace the whole layer with jumpers. Then while reading a RepRap page about home-etched RepRap electronics, I discovered this has a name - 1.5 layer boards. IE can be professionally produced as a 2 layer board, but can also be easily home-etched as a 1 layer board and the top layer replaced with jumpers.
For a few months I have been thinking that in the future I'd lay out my circuit boards so that as much as possible the traces would be on the bottom layer and the top would be only vias, so that they'd be easy to jumper or even replace the whole layer with jumpers. Then while reading a RepRap page about home-etched RepRap electronics, I discovered this has a name - 1.5 layer boards. IE can be professionally produced as a 2 layer board, but can also be easily home-etched as a 1 layer board and the top layer replaced with jumpers.