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Jeremy Blum

Jeremy is an Electrical and Computer Engineering Student at Cornell University. He has been building microcontroller projects since high school, from a prototype prosthetic hand with a novel control scheme, to a nerf gun that fires at the intruders and uploads their picture to the web.
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  • in reply to e14 Contributor

    Hi Brendan,

     

    To summarize your video, it looks like you've got a rotary switch (something like a 4-pole 5-way switch), and you want to have a delay in your software

    that corresponds to the switch position.

     

    You can use standard digital inputs, no need to use the analog inputs on your board (or configure the analog inputs to be digital inputs). On the rotary switch, normally the inner ring of contacts are the 'poles', and you can connect one of them to 0V. Then, connect the outer contacts to digital inputs on your board.

    (To confirm that you're using the correct pins before you plug it into the board, you could use a multimeter set to continuity check mode).

    Then, in your code, ensure that the digital inputs have 'pull-up' resistors enabled (see here for information on how to do this).

     

    When the rotary switch is in an appropriate position, then the pin will be forced to 0V, and this is something you can detect in your software.

     

    Search for a code example that detects an input condition, e.g. using digitalRead I think.

    Then, your code can have something like (my syntax may be incorrect):

    if (digitalRead(position0pin)==LOW) delay=2000;

    if (digitalRead(position1pin)==LOW) delay=4000;

    and so on.

  • in reply to e14 Contributor

    @Brendan

     

    Your video is somewhat adequate for the intended purpose, however, from an engineer's point of view  it is lacking in providing pertinent facts.  Such as the part number, data sheet, and source of the device in question which is apparently a multi-pole switch.   Therefore, anything I opine about is subject to change because I don't really know what device you are wanting to use.  That said, let us spread the Vegemite on the corn dodgers!

     

    I am wondering if a single analog input might be the best way to do your project.  If you have a packet of equal valued resistors, then it might work out if you were to link the outer solder tabs with the resistors all in series with one end being ground and the far end +5 volts.  Thus creating a voltage divider that can be read from the common center tab(s) with the analog input pin.  As far a programming it in the Arduino sketch, it simply calls for the correct application of the Switch/Case statement syntax.

     

    N.B.  I seem to recall that the analog inputs have trouble at one extreme value or the other of the range.   Therefore,  I recommend looking it up for yourself.  The solution, of course, is adding one more resistor in series with the others.

     

    If I were to do this project, I would set up the voltage divider so that I could use the modulo function, %, to read off the switch position almost directly.  For example:  Switch Position 1 = 105/1023, SP 2 = 205/1023, ... , SP 10 = 1005/1023  then the Var in Switch (Var) is computed directly by Var = int(( A0 - ( A0 % 100 )) / 100 )  which then allows the Case #:  to be indexed and controlled by the integer values of Var = SP which is 1 thru 10.

    [ Yes, of course, you could use the map() function.  It is your project after all. ]

     

    If your resistors are not of a consistant quality the +/- 10% may cause a little trouble.  If so, just add a little fudge factor to A0 of approximately 6% and it should work itself out.  ie  A0 = A0 * 1.06   before calculating the Var.

  • in reply to billabott

    @Brendan, I like Billabott's idea of maybe using a single analog input instead, like the 10k potentiometer in this example: http://www.oomlout.com/oom.php/products/ardx/circ-08

     

    I think it will be much easier than trying to deal with all those pins and possibilities.

     

    Cheers,

    -Nico