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Roger K.

Member Since: August 25, 2012

Country: United States

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See My GitHub for all of my Arduino and other programming projects (all free GPL3 code)!

  • I’ve found that any reasonable amp-to-speaker wire length radiates a ton of RF noise, detectable on AM and SW radio receivers. I made a little filter board using two 68uH series inductors and a parallel 1.0 uF capacitor on a tiny board, mounted directly to the amp board. This allows the use of longer speaker wires without spraying the whole room with RFI… and it doesn’t effect the audio quality one bit.

  • I’ve found that if you grossly overdrive the board, it shuts down (requiring a power cycle). It also has an output short circuit detection circuit (which shuts it down as well), I’m sure it’s not a “thermal issue”, since the chip runs cool even at full power.

  • Are these switches “tactile” (that is, clicky like a microswitch)?

  • Depending on which Arduino you have, try setting the analog reference to 2.5V or 1.1V. This will make the FULL SCALE analog input (i.e. 1023) to be 2.5 or 1.1 volts, giving you more “gain”.

    Note though that since you get a no signal offset voltage reading of 300 (which is 1.47 volts with a 5 volt reference), you will need to level shift the audio output signal if you use a 1.1 volt reference (because 1.47 volts is more than 1.1 volts and it would “peg” the analog reading at 1023).

  • This mic works surprisingly well, but one word of warning: Do not connect the audio output pin to a low impedance load. My son was playing with the mic and tried to connect a small 8 ohm speaker directly to audio out and ground (with a +3.3V supply). The little op-amp on the board was killed by this. I don’t know what the minimum recommended load impedance is, but probably to be safe send the signal to at least a 1K load or more…. maybe at least a 10K load.

  • That “day of the week” algorithm was not devised by Tomohiko Sakamoto in 1993, it was “devised” by a German mathematician Christian Zeller in 1883 see Zeller on Wiki

    Here’s a generic piece of code in C that implements Zeller’s Congruence:

    if (month < 3) { month += 12; year -= 1; }
    dow=(((day+(((month+1)*26)/10)+year+(year/4)+(6*(year/100))+(year/400))-1)%7);
    if (month > 12) { month -= 12; year += 1; }
    

    All variables are ints, and the names should be self-explanatory.

  • I see there is a spot on the PCB where an SMA connector can be soldered. Does anyone know if these traces are active (that is, if I solder on an SMA connector, will it work)?

    Thanks.

  • Could anyone tell me - is this button a “snap action” type? That is, does it have a “microswitch” type of action that makes a mechanical and tactile “click” when depressed or released, or does it just use ordinary contacts?

  • I also have a driver for this board: GitHub DS3234 Note that this driver does not need to use the Arduino SPI… it can use any pins you wish.

  • Something important to know about this (and other Saleae products) is that they fully support Linux 32 and 64 bit, as well as OSX.

    Obviously a big plus for those of us who use a REAL operating system. :)

No public wish lists :(