Member Since: December 18, 2009

Country: United States

  • I just realized, 10 years later. why the H-bridges blow: You need a flyback diode across the ringer because a ringer is an inductive load.You’re getting high(er) voltage spikes that the H-bridge isn’t able to handle. Try a 1N4007 or similar diode.

  • “…If I have anything in my hands that even sort-of looks like a laser he starts looking around on the floor for the red dot. He’s nuts…”

    That’s not a good sign. If they can’t catch and eat it, they become obsessed with it. It’s the dog equivalent of crack cocaine.

  • It’s a matter of physics and materials choice: near-IR is readily transmissible in glass and readily picked up by CCDs, hence the filter. With the exception of fused quartz glass, most glass is fairly (90+%) opaque to every wavelength but UVA. It’s easier to drop the IR filter to extend the range, (It “only” cuts the UV by about 80%.) but it’s more difficult to change the filter to re-limit the wavelengths to a different part of the spectrum. UV bandpass filters are expensive. Saying you rip out the IR filter, you still have to worry about the CCD’s construction: Does it have glass over the CCD module proper? Then you’re wasting money on a pass filter for that wavelength to just be blocked further down the optical chain.

    TL;DR: Don’t, but if you do, you want a “Wood’s Glass filter”. They can be found occasionally. Or you can hit up Newport (~.com/f/bandpass-filters) for a $350 specific wavelength UV bandpass filter. You would switch the IR filter out (rather than team it) with the UV passing filter.

  • That was the best filament review… … … …In the world.

  • And, another +1 for 1.75mm. Some of us have less expensive (Actually homebrew or very nearly to it) printers (I’ve a Prusa i3 variant made in China with a 1.75mm hotend.) The benefit to 1.75 is “bowden tube” type extruders and/or smaller steppers for filament feed. (More accuracy, better at fine detail because it requires less tweaking and has a higher extruder “traverse"speed. And is less likely to jam and strip the filament.)

  • Windows for my primary desktop (games and such) and my CNC mill’s controller, Debian (KDE, not GNOME) for my laptop and almost everything serious.

    If I had to pick a favorite? Linux. Being able to configure it (once.) and not to have to reboot twice every day (W10, I’m looking at you.) or after an in-place upgrade is nice. I only use windows because developers of certain pieces of (alternativeless) software and hardware (I’d buy one of your DSOs, but Linux support is “LOLNOPE”, especially when it comes to “But we need a custom driver, because of Windows”. WINE may not be an emulator, but it also Is Not an Alternative, in that case.) who w/don’t target Linux.

    But for most desktop stuff? I’ve even got my 55 year old father on Linux. He hasn’t managed to mess it up yet. He used to come to me every couple of months (“It’s broken.”) for a windows reinstall.

  • Try a kitchen range hood. Some idiot designed what could be done using 6 transistors, an LCD clock and a handful of other discretes (3 latches, basically) with a little MCU instead. For a two-speed range hood fan and light with a clock. Go to turn it on while cooking dinner; nothing. Clock frozen, steam condensing on the walls and ceiling. I had to go toggle the kitchen breaker because they left out a reset button.

    That’s rather unacceptable. Ask yourself while designing two additional questions: Can I X? and: Should I X?

    Yes, you CAN use an MCU for a range hood. No, you probably SHOULDN’T.

    Design perfection is not when there is nothing left to add, it’s instead when there is nothing left to take away.

  • Depending on the weight of the unit, I’d build the RC helicopter/plane/tank of doom. Failing that, I’d probably attempt conversion to {L,C}NG and find the generator head that matches it and have a decent backup power source. (LNG is cheaply delivered in my area.)

    Also, +1 for the safety enclosure. Turbines letting go at 50k RPM have a high likelihood of being lethal or permanently injurious to bystanders. Some of those fragments could have vastly more kinetic energy than a rifle bullet or a machete swung with intent to maim. If the compressor blades are longer than the width of appendages you’re not willing to part with, stick it in a box constructed of a minimum of half-inch thick steel. I’d also recommend carrying a pre-made tourniquet (like the Army’s “Combat Application Tourniquet”) so you can slip it over the stump of your leg/arm and torque it down to keep you from bleeding out if/when your turbine decides to take offense to being poked with a stick. Or the blades decide that they’ve had enough.

  • What, no development server and database cloned from the current live server+database just for testing? It’s not like you are using someone else’s bleeding-edge software product. Think of it this way: SparkFun Inc. is currently using SparkFun Inc’s Developers AG’s software product. Does this make sense? You’re using an internal product with what appears to be minimal testing. Things under development should never go live as the core of your business model without testing it until you know it’s right and reliable. By having an internal-only beta server that is being actively hacked on, you can do off the wall things like try a different DB, simulate purchases and so on, and do everything that the production server does currently without actually doing it for real. You test it by shadowing the current activities by the main server on the development server. That’s the best test, shadowing live usage and seeing if the results agree. Smaller changes and verification of correctness are important. smaller unit tests of one-shot changes are important. Not testing is nearly unforgivable for a developer. That’s like soldering up a PCB and wiring up a circuit that you know will be plugged into a wall and draw a couple dozen amps without first checking for shorts.

No public wish lists :(