Monopoly in Lights

Enriching the Electric Company

Gather Ye Crystals

After finally getting all the bits together, I was able to get the binary counter hooked up and working, based on some information I found on another site.  Connected an RGB LED to some of the higher value outputs, and watched in amazement as the little diode color shifted before my eyes.  White(ish), magenta, cyan, blue, yellow(ish), red, green, blank, repeat. After a few failed starts, seeing this was pretty happy-making.  Of course, it wasn’t going very fast, but that could still be okay.  So, it was finally time to try hooking up the LED driver to test the next step, which also required hooking in the Netduino, so I can ensure the driver knows to light the LEDs.

And that’s where things started to go a bit downhill.  After hooking things up, I could tell the Netduino was controlling the driver okay because it did actually light the LEDs, but suddenly the counter sample LED I hooked up wasn’t cycling nearly as fast.  Well, not usually, anyway.  In some instances it would speed up, then slow down again.  Regardless, it was never quite fast enough to actually make the driver do its PWM correctly.  (As a side note, the times the thing would speed up reasonably well seemed to be directly related to when I would actually physically hold the protoboard with my fingers.  Apparently human capacitance has an effect on this circuit as it stands, which is hardly the desired effect.)

My best guess right now is that the added power drain of the LEDs and the driver are somehow affecting the RC portion of the oscillator circuit, which makes that approach of questionable value.  The counter ‘s internal oscillator can also be used with an external crystal, however, so that was my next plan.  Rather than paying for shipping though, I decided to see what I could find on Amazon.  Did you know you can get a package of 50 crystals for about $7.00, with free shipping?  Did I need 50 crystals?  Not at all!  Did I feel better about paying $7.00 for 50 crystals than paying about $5-$8 for one crystal with shipping?  Absolutely!  So, now I wait for the crystals to arrive, and retest the circuit.

May 8, 2012 - Posted by | Electronics

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