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SparkFun will be closed May 25, 2015 for Memorial Day. Orders placed after 2pm on Friday the 22nd will ship out on Tuesday. Thanks!

Aurelio

Member Since: February 8, 2008

Country: United States

  • Adding the on-time and off-time is not a suitable way to calculate resonant frequency. A switch in a resonant state is closing with both the magnetic force and the spring compression from the previous cycle, thus is accelerating slightly faster than a switch that was at rest before. When the switch is opening, it is also assisted by the spring compression from the previous cycle. I think that explains why resonant frequency is faster than merely adding on and off times. To illustrate by mechanical analogy: an SUV won’t roll over if you swerve once, but if you swerve two or three times it might because each swerve builds up the potential energy on the springs as it bounces back and forth eventually building enough energy for the rollover. Of course, the closer the repeated swerves are to the roll mode resonant frequency of the suspension the greater the chances of roll over.

  • Do you guys sell the hand held part only? I cracked the ceramic element while trying to force a hakko tip (from here) onto it, apparently the inner diameter of some tips is slightly smaller than the ceramic element…??

  • I was able to figure it out. It works just as it should: 10k pot for contrast just like any other LCD

  • I am having trouble getting any visible output out of this LCD. Tried a 9k pot to get a voltage divider to supply V0, and at could get no output at all. Using an arduino pro mini 3.3v in 4 bit parallel mode. No clear indication here whether this is the correct method for powering the LCD contrast pin, or whether negative voltage is required.

  • I already tried to do this, short answer is that a mosfet would burn up driving a high inductive load like this. But you can add a “flywheel” diode to overcome this. The diode has to be able to pass as much current as the horn demands. Then PWM will vary volume, but not very smoothly. Might still do so smoothly enough for your purposes.

  • Thanks Niz….. have you built something around this board? I am interested. Also surprised at the cost of more modern gyros and accels. I just want to make sure accuracy is still decent and the board is tested…

  • It should! Please let us know how it turns out.

  • Why not revise the board with holes for mounting a standard CMOS/CCD lens mount? With a known tracking surface distance (or sensed) it should allow whatever dof you can find a standard lens for. One would have to account for the added zoom as a result of the tiny sensing area

  • It would. but while you can use an LM386 to drive headphones or a small speaker, I wouldn’t try the same with the 358. You could, but your maximum power is around 100mw.
    The main reason to use the 358 is that it runs on a single rail, and the output can swing from ground to like one volt less than VCC. I use it often as an active low pass filter to get low bandwidth analog outputs from PWM signals such as those from the Arduino.

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