mmgood

Member Since: May 13, 2009

Country: United States

  • Product ROB-10267 | about 3 years ago

    Agree. Has anyone actually tried to file a bug report?

  • Product ROB-10267 | about 3 years ago

    Your suspicion turns out to not match experiment. I measured the current on a 4.4 board and the silkscreen is incorrect. I can’t speak to what the other revs of the board were like but I can confirm that on my 4.4 rev board the chip gets too hot to touch when the pot is set to “MIN” (CW) and loafs comfortably with about 150 mA per winding when set to “MAX” (CCW, the intuitive “left==less” position).
    Seems that the claim “On this version (v4.4) we fixed the silk error on the min/max adjustment” is not quite true…

  • Product DEV-09147 | about 3 years ago

    Nope. Even doing that, I can’t get anything like full scale on that channel. That probably means the shipped firmware keeps it configured as an output and I am trying and failing to swamp that out with my driver.
    If / when I get a six-pin programmer going, I might try to load the firmware linked to up at top of this page and see if the second channel works as advertised with my cut LED trace mod.
    Until then, I have to also give this product a bad review for the hostile out-of-the box experience and a rosy description of function not in evidence. This is the first time I’ve ever felt really let down by a Sparkfun product. Bummer.

  • Product DEV-09147 | about 3 years ago

    Jimbo, all:
    I thought I’d leave a little trace of my work trying to get the promised two analog channels.
    I bought two of what look like the 1.1 version (no blue LEDs) quite some time ago. I too found the “connector” to be marginal, and I didn’t understand from the schematic what the second analog input channel, if any, is. I’d get strings of the form
    readingnumber PB4reading 0
    But from the published schematic nothing looks like a free analog input. All those zeroes in the third column made me wonder if it were a digital input. But then, every once in a while by running my fingers around and getting resistive or capacitive coupling, I get something like
    readingnumber PB4reading 2
    Things that make you go “Hmmm”. Whatever the second channel is, it’s much less sensitive (lower Z, I guess?). From mjy58’s commentary it might be PB3, I suppose.
    I can’t tell how to get the second channel to work safely from the info Sparkfun provided and pointed to. I can get one channel, so it’s not utterly useless. And it’s a cute hack. Going from what mjy58 wrote and other hints on linked pages:
    From the fact that the firmware on the ones I’ve got seems to flash the yellow LED on PB3 immediately after connection to the USB port, even if I cut the trace to get rid of the 470 ohm + yellow LED load on that pin, whatever analog source I connect is gonna see that pin treated as an active high output for a moment after plugin. I suppose that can be mitigated with a 10k to 20k resistor fed by a buffer amp.
    There are worse things than a little signal conditioning, I suppose.

  • Product DEV-09217 | about 3 years ago

    Umm, no. A quartz crystal with the needed two 18-to-22 pF capacitors is going to be orders of magnitude more stable and accurate than a typical ceramic resonator. Ceramic resonators are cheaper, and easier to connect, but they’re usually only rated at + or - ½% accuracy. Wristwatches, on the other hand (oh look! wordplay!), use quartz crystal elements because you can routinely get better than 10 parts per million accuracy with them.
    Strictly, both are “resonators”, but common tech parlance calls just the looser tolerance part that.
    Cheerio.

  • Product BOB-10031 | about 3 years ago

    OK, I might be dumb or just tired, but how come the female Micro B breakout only has four pads and the male one has five? I’m not incredibly conversant with the Micro B spec; apologies.

  • News - Using a Multimeter | about 4 years ago

    My chief point is that this stuff should be up in the “measuring current” section, rather than down in “changing the fuse”. But that’s just me.

  • Tutorial - How To Use A Multimeter | about 4 years ago

    Not a bad tutorial. BUT.
    If it were up to me, I’d include a BIG caveat about what to do AFTER you measure current /right in your section about how to measure it/. As a retailer of electronic test equipment as well as having years of tech experience, I’ve noticed that one of the big (classic) mistakes people make is configuring their meter for measuring current, doing that, but then forgetting to switch the leads and/or rotary knob back to volts when they’re done, and when (minutes, hours, or days later) they pick up the meter and try to measure volts… WHAM. Bye-bye fuse.
    Another way to deal with this is to take the approach of ALWAYS checking the lead configuration and rotary knob setting BEFORE measuring voltage… rather than blithely going ahead and “measuring volts with a dead short”.
    Being prudent, I try to remember to do both. Just in case.
    Putting this commentary down under “changing the fuse” seems, well, suboptimal. ;)

  • News - Using a Multimeter | about 4 years ago

    Not a bad tutorial. BUT.
    If it were up to me, I’d include a BIG caveat about what to do AFTER you measure current. As a retailer of electronic test equipment as well as having years of tech experience, I’ve noticed that one of the big (classic) mistakes people make is configuring their meter for measuring current, doing that, but then forgetting to switch the leads and/or rotary knob back to volts when they’re done, and when (minutes, hours, or days later) they pick up the meter and try to measure volts… WHAM. Bye-bye fuse.
    Another way to deal with this is to take the approach of ALWAYS checking the lead configuration and rotary knob setting BEFORE measuring voltage… rather than blithely going ahead and “measuring volts with a dead short”.
    Being prudent, I try to remember to do both. Just in case.

  • News - Beerware is the Old Open … | about 5 years ago

    Ack Pthpbthpthtb. Make that a FIO 328 question. :\ :)

No public wish lists :(