with fewer connections. The RTClib library makes using
this mini board very easy. RTClib can be found at GitHub
The MSGEQ7 circuits are a little more involved, but
with the addition of four capacitors and a resistor, you
have a single-channel graphic equalizer display; with two,
you get a display for stereo output. Using this circuit is
fairly straightforward. After sending a reset pulse, the
strobe line is pulsed low and the output is then read using
an analogRead() command. This is repeated seven times,
giving numeric values from 0-1023 for frequency channels
with peaks at 63 Hz, 160 Hz, 400 Hz, 1 kHz, 2. 5 kHz,
6. 25 kHz, and 16 kHz. The complete schematic for my
design is shown in Figure 2.
I mounted my RGB LED strips on a 1/4 inch piece of
good quality plywood. Reinforcement pieces of 3/4 x 1
inch wood were glued around the edges of the plywood
in addition to two added ribs to give the plywood rigidity.
Small notches were cut in the edges of the plywood to
give the connecting wires a path to the underside of the
plywood. A number of holes must also be drilled in the
ribs to allow the connecting wires to pass through.
The driver circuit was built on a breadboard with
point-to-point wiring. This board was enclosed in a 158 x
90 x 60 mm plastic project box. The sides of the box were
pierced with holes for mounting two 5. 5 mm jacks for
nine volt/one amp and five volt/three amp power supplies
(the wall wart type). The five volt power supply is only
40 November 2016
■ FIGURE 3. Edge of the plywood board the
RGB LED strips are mounted on, showing the
■ FIGURE 5. Inside the project box, showing component
■ FIGURE 4. Box array, with each box fitting over two
LEDs to isolate the colors.