IoT On-Air SIgn

In this tutorial, you'll learn how to build an internet connected On Air Sign. It will light up whenever your favorite Twitch channel start streaming. You can use this as visual notification or if you’re a broadcaster, this will let the people around know to be courteous!

It’s uses an Adafruit HUZZAH with ESP8266 or you can optionally use an Adafruit Feather M0 with WiFi.You’ll also need a strip of NeoPixel LEDs.

Parts List

Tools & Supports

Soldering Iron with Solder
26AWG silicone coated stranded wire
Wire Strippers
3D Printer with Filament
Double-sided tape
8x #4-40 flat Phillips machine screws

Prerequisite Guides

Walk through the following guides to get familiar with the hardware usd in this project.

Adafruit HUZZAH ESP8266 Guide

Reference Connections

Use the circuit diagram to reference for connecting the components together. The diagram does not depict exact wire lengths or size of components.

Please take note of the connections on the NeoPixel Strip. The order of the connections vary from strip to strip.

Pin # 12 from HUZZAH to Data In on NeoPixel Strip
GND from HUZZAH to GND or "–" on NeoPixel Strip
USB from HUZZA to +5V or PWR on NeoPixel Strip

Power

Use a 5V USB power supply and a microUSB cable to power the circuit

Materials

We suggest using PLA material but your free to use ABS, PET or exotic composites like wood, metals and others. The parts are listed in the tablet below.

bot-case.stl	Bottom case half. HUZZAH and LED strip are mounted to this.
top-case.stl	Top half of case.	x
face.stl	Panel with "On-Air" text stencil cutout.	x
diffuser.stl	Blank diffuser piece should be printed in transparent/white material.	x

Slice Settings

Depending on your 3D printers hardware, you'll need to use your prefered slice settings. The parts are oriented to print "as-is" and doesn't require any support materials (very minimal overhangs).

These are the slice settings we used on our Printrbot Play, sliced using Simplify3D

220C Extruder (on a non-heated bed)
20% Infill
2 shells/parameters
4 top and bottom layers
1.0 Extrusion multiplier
0.48 Extrusion width

Customize Design

The enclosure parts are available to modify and download. Click below to download the source. Size it to fit the bed of your 3D printer.

Download Source

Download STLs

3D print the files "as-is" if they can fit on the bed of your 3D printer (case is 220mm x 90mm)

Download STLs

Adafruit HUZZAH 8266 Arduino Libraries

Be sure to follow the guide below to install the board and libraries.

Follow Adafruit HUZZAH EPS8266 Arduino Guide

Arduino Sketch

The arduino sketch will connect to the Twitch API and determine if the Twitch channel is currently streaming - if so, the Feather will turn on some NeoPixels to light up the sign. In the sketch, you'll need to add your WiFi credentials, change the number of pixels you're using and your desired twitch channel.

Download the sketch from the github repo linked below.

Arduino Sketch

Twitch API

If you're interested in reading how the twitch API works, click on the link below.

Twitch API Guide

Prep Wires

Let's start by preparing the wires for this project. You'll need six pieces of wire. I suggest 26AWG silicone coated stranded wires. Measure each wire to about 9cm in length.

Use wire strippers to remove about 3mm of insulation of the tips of each wire. Tin the exposed tips of each wire by heating it up with the soldering iron and applying a bit of solder.

Adafruit HUZZAH ESP8266

Secure the HUZZAH ESP8266 to a Panavise Jr. or helping third hands. Tin the USB, #12 and GND pins. Solder wires to these pins. They don't have to be color coded but it does help tell them apart.

Cut NeoPixel LED Strips

Next, you'll need to cut the NeoPixel LED strips into two pieces. Use the length of the enclosure to determine the right size (it should be a little longer than the diffuser).

If your using a high density NeoPixel strip (like the 144 LEDs per 1m), you may need to remove a "sacrificial" pixel. This is where you need to cut a pixel off so that you have more exposed pads to work with. Otherwise, you may find it difficult to apply solder to a pad thats cut in half.

Wire NeoPixel LED Strips

Now we need to solder the three wires from the Adafruit HUZZAH to one of the NeoPixel LED Strips.

But first, apply solder to each pin on both ends of the NeoPixel LED strips. While heating up the tinned pin with the tip of the soldering iron, quickly place a wire to solder it in place. Gnd to -negative, USB to +positive, and #12 to data in. Then, connect the remaining three wires to the end of the first NeoPixel strip.

Connect NeoPixel LED Strips

Now we need to connect the two NeoPixel strips together. Solder up the three wires from the first NeoPixel LED strip to the second. Make sure the marked arrows are flowing and not pointing towards each other. A pair of helping third hands will make it easier to solder.

Test Circuit

Now is a good time to test your wiring before mounting it to the case.

Plug in a micro USB cable into the Adafruit HUZZAH and into your computer. You can upload the Arduino sketch or an example NeoPixel demo (like the simple sketch) to test the NeoPixel LED strips - just make sure to update the sketch with the correct number of pixels and pin 12.

Assemble Case

If everything works as expected, it's safe to start mounting the circuit to the 3D printed enclosure!

Tap Mounting Holes

Before securing the HUZZAH board to the case, it's a good idea to tap the holes. Use a #4-40 machine screw to do this. Start by placing the screw over the mounting hole and slowly fasten it in - try your best to keep the screw straight so it doesn't go in at an angle. This will create threads. Do this for each hole.

Secure Adafruit HUZZAH

Place the HUZZAH board over the standoffs on the bottom case and fasten the screws. DO NOT fasten them all the way through - otherwise the screw will poke throught the case. You only need to fasten it a few turns, until the board is secured to the case.

Stick NeoPixel LED strips

Add pieces of double-sided tape to the back of each NeoPixel LED strips and stick it to the inside of the case. Reference the photo for best position.

Secure Case Halves

Insert 6 #4-40 3/8 flat Phillips machine screws into the back of the case and fasten them in until they poke through the top. Place the top half over the bottom half and hole them together while fastening the screws all the way in.