Sparkling LED lights are pretty to look at and make fun
displays for holidays or special occasions.
CheerLights that are controlled by tweets
and that change color in synchronization with all the other CheerLights around
the world add an element of interest and community that sets them apart from
regular LED lights.
This article explains how you can build your own sparkling
Cheerlights display using a Particle Photon Wi-Fi microcontroller and LED
strips that read the current CheerLights color from ThingSpeak.
The electronics and power supplies are mounted on plywood
sheet inside a weatherproof box.
A close up picture of the Shield Shield board shows the
signal connections to the four Neopixel strips.
The photo shows use of a terminal header for convenience. Note the red jumper wire between VIN and 5V
used to bypass the voltage regulator on the Shield Shield. Five jumper wires (not shown) are soldered
beneath the board from pins IO10, IO11, IO12 and IO13 and ground to the
terminal. As an alternative to using a terminal header the jumper wires could
be pushed into the board headers or soldered on directly.
Close up of Shield Shield board with wiring
The following sketch illustrates the wiring in more
Ethernet cable is used to connect the power and signal wires
to the LED strips. The brown/brown-white
twisted pair are connected together to carry ground and the orange/orange-white
pair together carries +5 volts. The
blue/Blue-white twisted pair is used for the signal. A 100 ohm resistor is
connected in series with each blue-white signal wire. Each power supply powers two 10 meter long
LED strips and a 4700 uF capacitor is mounted on the terminal strip across each
power supply terminal.
Note: it is important
to keep the length of the signal wires less than about two feet long. The signal driving the LED strips operates at
about 800 kHz and, since the drivers are unbalanced, it is not possible to send
the signal down long wires without it becoming too distorted to operate the
Follow the Particle
instructions on their web site to connect your Photon to your Wi-Fi network
and associate it with your account using their app or web IDE.
The code is published on Github. Note that after you have copied the code to
the IDE you will need to delete the two #include statements for the ThingSpeak
and neopixel libraries and add them back again for the Particle IDE to actually
include the libraries.
Enjoy Your Display
If everything is working correctly your CheerLights display
should gradually light up
along the strips with a sparkling effect.
Sending a Tweet with the
hashtag #CheerLights, and a valid CheerLights color anywhere in the text, will
change your display to the color that you just tweeted.