gasstationwithoutpumps

Member Since: December 18, 2011

Country: United States

  • Sigh. I'd just renewed my subscription a month ago.

    I think that the Bay Area Faire was declining in attendance, because it was so crowded at the peak that it was no longer fun. The size was dropping back to the limits of the capacity of the venue.

  • The biggest EOL problems I've had are with low-cost through-hole power FETs. They seem to be dropping like flies. I was changing the FETs for my course every year! Some of the packages had very short leads and would not stay firmly in the breadboards.

    I finally decided to have the students solder SOT23 FETs to a breakout board, so that we could use the same part numbers each year and so that the header pins were long enough to stay in the breadboards.

  • Red, blue, and yellow are not subtractive primaries: cyan, magenta, and yellow are. Your subtractive Venn diagram is misleading.

  • Asking people about their ages and what they studied in school/college would be interesting. Jameco's similar survey a few years indicated that almost all their hobbyists were retirement age.

    As for Makerspaces, I agree that cost and accessibility are the main barriers for me. The closest makerspace is close enough, but too expensive ($45/month to get access to hand tools no better than I have at home, $90 a month to get 4 hours/week of reservable time on the good tools (laser cutter, 3D printer), $120 a month to get 8 hours/week (adding the Shopbot to the allowed tools), $240 a month to get 12 hours/week). If I had a project that actually used that much of the equipment time, the prices would be good (under $6 an hour), but I tend to have no time for most of the year, then I want a chunk of equipment time all at once, so the hours/week subscription model doesn't make much sense for me.

    The local community college has a makerspace that is $145/month ($105/month if you take two of their training courses). There is $20 worth of materials included in that fee. It is a 50-minute bike ride away, so I would be hard pressed to go there often, and only 4 hours a month of laser time and 10 hours a month of 3D printer time are guaranteed in the membership.

    Although I would probably like the camaraderie of a makerspace, I have a hard time justifying the expense, which would buy me a lot of tools and parts that I could use without reserving them a week in advance.

  • You only have zip ties holding the stepper motors in place?? Those screw holes on the face of the stepper motor are there for a reason—to keep the motor body from moving instead of the shaft. There should be plates screwed to the motor and slotted into the support to take the reaction torque.

  • Why such high temperatures? Only the bottom two temperatures seem useful for electronics soldering. Is this tool intended for jewelers doing silver soldering?

    The round body looks like a roll-off-the-bench burn waiting to happen—is there a stand with a cage sold separately?

  • Incidentally, one can get very nice I vs. V curves with an Analog Discovery 2 and a resistor, up to the power output limits (5V and 700mA using the power supply or about 100mA using the function generator). The function generator or power supply can be driven (slowly) with a triangular wave, so the I-vs-V curve can be collected in one pass using the two differential scope channels. I've used this technique for DC characterization of several parts, including LEDs.

  • A load for testing power supplies is going to get hot somewhere—it's function is to dissipate a controlled amount of power. The linear solution here makes more sense than a switched solution, because a lot of power-supply testing is looking at how much ripple it produces and introducing more ripple from the adjustable load would hide that. Also, one might want to look at the power-supply response to step increases in current, which an inductive load is not capable of emulating.

    That said, I don't see the attractiveness of the PSoC line of microcontrollers here—the analog circuitry is just being used to compensate for the inadequate resolution of the DAC and ADC. A KL26, such as in the Teensy LC board, would be a simpler solution.

  • Isn't the button a little small for a foot pedal? Compare with pedals like http://www.airturn.com/bluetooth-pedals or http://www.guitarcenter.com/Moog/EP-3-Universal-Expression-Pedal.gc

    I see that some guitar effects pedals do just use a small switch like the one here. Guitar players, how well does that work, compared to the bigger pedals?

  • This board looks like it is over-engineered to me. Using a $5 accelerometer when a 3¢ vibration switch would do seems a little strange (unless you are a company that makes accelerometers).

    I tried designing an analog circuit that would handle more output power and work over a wider output range on a smaller standby power budget: https://gasstationwithoutpumps.wordpress.com/2015/03/28/ideas-about-vibration-detection/

    I've not tried building it, though (too many SMD parts). If anyone tries it, please leave a comment on my blog!

No public wish lists :(