The circuit won’t mean a thing if you don’t set up the lights for it to con-
trol. That’s where the two groups of LEDs and resistors come in. They
include- LED1–LED8 to light the display for the high-frequency circuit and
LED9–LED18to light the display for the low-frequency circuit. - R11–R18 in the upper circuit and R28–R35in the lower circuit are
resistors, that in series with LEDs, limit the current running
through the LEDs to approximately 10 milliamps.
Building Alert: Construction Issues .............................................................
Behind the musical score, we drew on the box that holds the circuit, and all
the resistors and LED leads are soldered together. To make sure that leads
that get bent and touch don’t cause a short, they need to be protected.
Rather than using electrical tape, we use liquid electrical tape to coat the
exposed leads.Wires run between the circuit board resting on the bottom of the box and
the LEDs that you insert in the top of the box. Be sure to cut your wires long
enough so that when you open the box (which moves the LEDs in the top far-
ther away from the circuit in the bottom of the box) that you don’t rip out the
wires. Also be careful that you leave room to tuck those long wires inside the
box when closed so they don’t poke out the sides or get caught in the hinges.
This is one case when stranded wires work better than solid wires because
they are more flexible.Perusing the Parts List ..................................................................................
It’s off to your nearest electronics store or online vendor for those electronic
parts you use to build the circuit and assemble the box that contains all
those LEDs.The circuit that transforms music into your dancing light show involves the
following parts, several of which are shown in Figure 5-3:2.2 kohm resistor (R1)
Eight 220 ohm resistors (R11–R14, R28–R31)92 Part II: Sounding Off!