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Member Since: April 5, 2010

Country: United States



I’m addicted to MCU/embedded design. So little time, so sad.


electrical engineer


Thermo Fisher Scientific

Programming Languages

LabWindows, C, AHK, assembly, some VB




instrumentation software, test software, windows programming, embedded programming, hardware design


electronics, sci-fi, the usual suspects



  • Mike, is this why my serial port emulator (RealTerm, what else?!) is getting very garbled data? I’ve checked and rechecked all the settings. But it’s total garbage out.

    Frustrating thing is that RealTerm has an “invert” checkbox but it doesn’t seem to be doing anything to the displayed data. I guess I could just put it in hex mode, do an inversion manually on the bytes to confirm?

  • Eureka! It’s so wonderful to finally know that my “condition” has a name! Just shining a light on the problem makes it less scary for me. Thanks.

  • The schematic on this little gizmo is kinda screwy in my opinion. It works, but is somewhat messy in the software logic. I get that the designer was going for economy of port pins (only 3 is good), but with most *duino (or other MCU) boards, port pins are NOT in short supply.

    I much prefer a clean row/column schematic, which helps the software weenies get their logic orderly. So in this product, a row/column scheme would have yielded 5 port pins (2 rows x 3 columns) and more ordered code.

    < / 2 cents>

  • Resource planning is such a fascinating, if a little mind-numbing, topic. I’ve had the pleasure – or great unfortune, depending on your perspective – of sitting through two of these kinds of meetings in my career. And 100% resulted in some level of shouting matches erupting. It’s amazing how territorial people can get over their departments and their processes.
    Good luck in your MRP adventures!

  • That’s correct, halfstop. The number of loads (devices), or the bigger the load (a device that requires a bunch of current), then more current will (want to) flow through the board.
    But as TimeLord points out, the limiting factor in this circuit will be the traces on the board, not the relay. Those traces apparently will only support 5.5A. In other words, they will burn first if you have too much total load hooked up.

  • It looks as though Digikey has now added this functionality to their search results pages. Quite nice actually, as they also allow for filtering on quantity (to remove the reel pricing).

  • Is it just me or are the PTHs not quite on 0.1" centers? I suppose that could be by design, so that there’s some friction to keep the header in place while soldering. If so, that’s a super clever idea!

  • Neat project! I did something very similar a few years back:
    Only mine used a 555 timer for the timing logic.

  • Maybe I missed this, but are these truly counterfeit? i.e., do they somewhat function the same as the genuine ATmegas?
    Or are they some other die in a faked package?

  • Ha! Brilliant script.