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SparkFun will be closing today at 12pm MT for a company outing. All orders placed before 2pm MT will still ship out same-day. Thanks!

Dickcheney

Member Since: May 19, 2012

Country: United States

  • You know, I have one simple request, and that is to have sharks with fricking laser beams attached to their heads!

  • I usually make it a rule to only leave an adapter plugged in unattended (to charge a battery or power something that I want to keep on) if it is UL listed.

  • An electric striker involves cutting a bigger hole in your door frame, which you can’t really do with a soldering iron, a computer or a pair of wire cutters. If you’re more electronically inclined than mechanically inclined (either in terms of the tools you have or your skills) this would be a good way to build your own “smart” lock.

  • Do not touch the operational end of the device. Do not look directly into the operational end of the device. Do not submerge the device in liquid, even partially. Most importantly, under no circumstances should you (static)

  • Hey, they could keep track of how many of these things they have to sell. If they notice that they have a lot of these, they’d be like “Hey! We have too many grab bags! The pick and place machine must be broken again” =)

  • For a consumer device, I would say a “good way to fail” would be: 1. In large type, put a very simplistic description of the problem. For example, in this case, it could be akin to “Sorry, the internal computer froze”. Or, if the computer itself thinks there’s an issue with the temperature sensor or some other part, it could say “Uh oh! The temperature sensor is busted!” 2. Don’t just say “Call (customer service)” for every error, but instead, give some “user maintenance” instructions, if applicable, (“Please turn the machine off and then back on” for a kernel panic) and then something like “If the problem occurs frequently, please contact (customer service)” 3. Put the nitty-gritty details below that message in smaller print.

    A good example of varying amounts of “fault tolerance” would be vending machines and arcade games. Protecting the core function would mean greater profits for the owner. However, if the core function is impacted directly by the failure, a better (but likely more expensive) design would detect such a fault and indicate it to users somehow (display “OUT OF ORDER” or “Err” on the display, turn off the machine’s lights, etc) Although the technology to implement such things has existed for several years now, vending machines are usually built to last and/or be repaired, so many “dumb” machines are still in active duty.

  • I have seen a microwave oven that runs the fan for a little while after use, presumably to cool down the magnetron and transformer. However, said fan is on the same circuit as the light, so the microwave appears to still be running to someone not used to that model. (Albeit with the timer displaying “0”)

    One failure mode I have seen on microwaves in the past is that the relay, or it’s driving signal, became stuck on, resulting in the microwave “cooking” constantly whenever the door was shut. With a normal microwave, this would be quickly noticed because the fan and light would also go on when you shut the door.

    But if you became accustomed to the “fan cooldown mode” the microwave would APPEAR TO BE WORKING NORMALLY EVEN THOUGH IT IS SUFFERING A CATASTROPHIC FAILURE! In other words, you could be standing right in the kitchen, look directly at the runaway microwave, and then think it has stopped heating and walk away!

  • I use these boards for many of my projects. I have a roll of bare solid 22 (or 24?) gauge wire that I do point to point with on these boards. I’ll often make power “buses” as well, by having a bare wire next to some holes I plan on soldering components to later.

    Some people use the legs of the components themselves to make short-distance connections. I have done so in the past, but I try not to anymore because I believe it would make future replacement of said component a royal pain. Other people like to just run over two holes they want to connect with a big solder bridge. This won’t hold together in the long term because solder is relatively brittle compared to an actual wire. It is also easier to see a broken wire than a solder joint that has separated.

    http://electronicsclub.info/docs/stripboardplan.pdf

    This isn’t actually specific to just stripboards as the title would suggest.

  • For those who want to somehow protect their circuits from “epic failure” consider this. A fuse will not only protect your circuit, but it will appear “blown” (i.e. open) thus giving you a clue as to why your circuit isn’t working.

    A PTC is more convenient because you don’t need to replace it, but because it is self-resetting, your circuit will appear “dead” but the PTC will still appear as a low resistance (maybe not a dead short) without power. However, it will be hot when powered and “activated” so you could do the “switch and feel” method if your voltages are safe to touch (most PTCs can’t handle high voltages anyway)

  • The voltage rating is kind of like the rating on a capacitor, in that you don’t want to use a (say) 32 volt fuse in a 110 volt circuit. The reason being is that the higher the voltage, the longer the distance that an arc can form. If the voltage is too high, the fuse cannot safely interrupt the current. An arc might allow current to just keep on flowing until something else fails, or the fuse could get hot enough to damage/ignite things around it (which somewhat defeats the purpose of having a fuse)

No public wish lists :(